Electrically evoked cortical potentials recorded directly from cochlear implant system: Feasibility in pediatric users and clinical relevance

Electrically evoked cortical potentials recorded directly from cochlear implant system: Feasibility in pediatric users and clinical relevance | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Electrically evoked cortical potentials recorded directly from cochlear implant system: Feasibility in pediatric users and clinical relevance Suhail HabibAllah, Chen Chen, Joseph Attias This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6170473/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 02 Jul, 2025 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract Intracochlear electrodes in cochlear implants (CIs) offer a novel method for recording auditory brain activity without external EEG equipment, addressing challenges in pediatric CI users. This study tested the feasibility of recording electrically evoked cortical auditory evoked potential (eCAEPs) directly via the CI system. Twenty children and three adults with bilateral Advanced Bionics CIs participated. A brief electrical stimulus was delivered to one CI, while the contralateral CI recorded responses using a basal electrode referenced to the case. Each session included stimulus and non-stimulus sweeps, with averaging over 600 ms revealing clear eCAEP patterns. All participants exhibited obligatory P1, N1, and P2 peaks within a test duration of under five minutes. The method showed good test-retest repeatability and expected latency shifts occurred with stimulus level adjustments. Compared to scalp recorded EEG, intracochlear recordings produced significantly larger amplitudes with similar latencies. Early-implanted children displayed distinct eCAEP patterns, and better performing CI users had earlier P1 responses. This recording approach provides a robust, non-invasive tool for monitoring CI users, particularly young children, offering potential advancements in post-implantation assessment and intervention by eliminating external equipment while ensuring reliable recordings. Biological sciences/Neuroscience/Auditory system Biological sciences/Neuroscience/Auditory system/Cochlea Biological sciences/Neuroscience/Auditory system/Cortex Cortical Auditory Evoked Potentials Intra-Cochlear Recordings Pediatric Scalp Recordings electrical stimulation Brain Objective measure Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Introduction Brain plasticity plays a crucial role in optimizing outcomes for children with congenital hearing loss who receive cochlear implants (CIs) 1 , 2 , 3 , 4 , 5 , 6 . During critical developmental periods, the brain's auditory pathways demonstrate remarkable adaptability, allowing them to reorganize and process new auditory signals provided by the CI 2 , 7 , 8 , 9 . This neuroplasticity facilitates the development of age-appropriate speech and language skills, particularly when implantation for congenital hearing loss occurs early in life 10 , 11 . Delayed implantation can result in cross-modal plasticity, where the auditory cortex is repurposed for other sensory modalities such as vision, potentially impeding auditory rehabilitation 12 , 13 . Early intervention mitigates these effects and maximizes the restoration of auditory cortical function, leading to improved long-term language and social outcomes 14 , 15 . Neuroimaging noninvasive techniques, such as functional MRI (fMRI) and diffusion tensor imaging (DTI), have been instrumental in demonstrating brain plasticity in cochlear implant (CI) users. 16 , 17 , 18 , 19 . Positron Emission Tomography (PET) is an additional neuroimaging technique using a radioactive tracer to demonstrate metabolic auditory brain activity following cochlear implant 17 , 20 . All those techniques have excellent spatial resolution revealing changes in neuronal activity, in connectivity tracts and white matter within the auditory cortex post-implantation, with a gradual normalization reflecting restored auditory function. However, they are limited by their low temporal resolution, high cost, the need for radioactive tracers, and unfriendly and challenging test-environments, making it less feasible for use in young children or routine clinical settings. Functional near-infrared spectroscopy (fNIRS) on the other hand, is a non-invasive and more accessible alternative that measures changes in oxygenated blood flow in the brain, providing real-time data with moderate spatial resolution. It has been used to monitor brain activity during auditory tasks in CI users, and studies have shown that it can detect functional changes in the auditory cortex post-implantation 21 , 22 . However, the relatively low temporal resolution, the need to place a cap with multiple source and detectors on the scalp and the necessity to avoid head movements, all making this technique limited for working with young children. Electrophysiological techniques, particularly cortical auditory evoked potentials (CAEPs), are valuable tools for assessing brain plasticity after cochlear implantation, especially in young children where behavioral measures and subjective feedback are limited. These non-invasive measures offer excellent temporal resolution and provide objective insights into auditory cortical development and adaptation to electrical stimulation 1 , 23 , 24 , 25 , 26 . Scalp recorded P1 component of CAEPs serves as a biomarker for central auditory maturation, allowing researchers and clinicians to track changes in neural responses over time 27 , 28 , 29 , 30 , 31 , 32 . In children with hearing loss, the P1 latency typically shows age-related decreases and morphological changes, reflecting the development of auditory cortical pathways 12 , 33 , 34 , 35 , 36 . Studies have shown that children who receive cochlear implants before the age of 3.5 years often exhibit normal development of P1 latencies, even if these were initially delayed 8 , 15 , 37 . By providing an objective measure of auditory cortical development, the P1 CAEP aids in evaluating the success of early intervention and clinical management in pediatric cochlear implant recipients 38 . However, clinical implementation of scalp recorded CAEPs faces significant challenges in pediatric populations. Key limitations include complex electrode attachment, specialized equipment requirements, and the need for subject immobility during recording. These factors make the examination difficult for young children, who may find it challenging to maintain prolonged cooperation. Consequently, there is a need for more child-friendly approaches to neurophysiological auditory evaluation. By overcoming the practical constraints of traditional CAEP recordings, the ability to record the P1 potential directly from the cochlear implant (CI) system, without the need for external equipment provides a child-friendly solution for neurophysiological auditory evaluation. In the past, different intra cranial or intra cochlear approaches to record in adults CI users eCAEPs using an external EEG system for analysis, have been demonstrated. This included invasive recording technique by means of temporary implantation of a special epidural electrodes 39 , or by using an electrode grid, implanted contralateral to the stimulus side in the course of an epilepsy surgery 40 or by means of implanted a connector percutaneous attached directly to an external EEG recording system, in numerous adult CI users 41 . Although these studies provided important insights regarding the significance of intra-cranial or cochlear recordings in improving the quality and amplitude of responses, they cannot serve as a clinical tool for standard monitoring and implementation in implant recipients, neither in adults nor especially in children. To circumvent the invasive approach, methods were proposed based on closed-loop systems for recording and processing cortical responses using electrodes implanted both within and outside the cochlea, as well as utilizing the speech CI processor of the cochlear implant 42 , 43 . Both studies used the CI Nucleus 24, Cochlear Corp., Sydney, Australia and external EP system for off analysis. Due to severe memory limitations for recording long latency brain responses, which require sampling over extended time windows, researchers were compelled to use shorter sampling windows designed for short latency auditory nerve responses. These shorter windows were then concatenated to achieve cortical responses within approximately 300 ms windows. Although these methods demonstrated cortical responses that aligned with those obtained through standard techniques, the concatenation process resulted in significantly prolonged testing durations. Furthermore, substantial hardware and software modifications to the implant systems were necessary, greatly limiting their clinical applicability, particularly in adults and even more so in children. Attias et al. 44 were the first to demonstrate the feasibility and validation of direct recording of CAEP in long time window of 0.6 second post stimuli in bimodal children and adults using Advanced Bionics cochlear implants. In this approach, acoustic stimuli were presented in the ear with residual hearing triggering the contralateral ear with AB CI system to directly record CAEP response. The acoustic CAEP responses highly correlated with the traditional scalp recorded CAEP by an external EEG system. The duration of the test for 120 stimuli lasted approximately 3 minutes and was tolerated by all subjects. Using a similar intra-cochlear montage (apical and case electrodes) and the built-in backward telemetry of AB system, combined with an external EEG system, 45 demonstrated the feasibility of recording ACEP in five bimodal adult CI users. In two of these CI users, presenting attending and un-attending acoustic stimuli to the acoustic ear, showed the potential use of ACEP for decoding auditory selective attention. Recently, 46 further showed the feasibility of direct recording of CAEP by the AB CI system in responses to speech electrical stimuli in 7 adult CI users. The CI recorded eCAEP responses well correlated with the scalp CAEP responses triggered by the stimulating CI system and recorded through external standard EP system. This study aimed to validate and demonstrate the feasibility of electrically stimulated and directly recorded intracochlear auditory cortical evoked potentials (eCAEPs) using the Advanced Bionics cochlear implant system in a group of 20 children (ages 4–17) and 3 adults (ages 21–28). The research focused on examining the repeatability of eCAEPs within and between testing sessions, as well as comparing the waveforms of intra cochlear eCAEPs with simultaneously recorded standard scalp evoked potential. Additionally, the study conducted a preliminary analysis of the relationship between eCAEPs and the electrical level stimulation, the age at implantation, as well as their association with speech and auditory outcomes. This comprehensive approach aimed to provide insights into the reliability and potential clinical applications of eCAEP measurements in pediatric cochlear implant recipients. RESULTS The application of the recording of cortical recordings directly by the CI system in 20 children and the 3 adults, revealed that eCAEP could be recorded from each functional CIs of the participants. All the subjects tolerated the testing well, and no one requested to end the testing before completion. The recording procedure took approximately 4 minutes for each run of 150 electrical stimuli. The eCAEP of each participant was evaluated and the peaks were identified by the first and last authors of the study, who are experienced on evoked potentials (SH and JA). Figure 1 illustrates the eCAEPs recorded from 9 CI users out of 20 children who participated in the study. The decision to present data from 9 children was due to space limitations and the aim to provide representative examples. These cases illustrate the range of responses observed, with additional eCAEPs from other participants shown later in the study. The eCAEP’s components (P1,N1, P2 and N2) of the eCAEP were identified and marked for each study participant. As can be visually observed from the figure there is considerable variability in the latencies and amplitudes of the components among the subjects. In some cases, the P1 component (S9; S15) and the P2 (S3;S5). Figure 2 presents the variability in individual eCAEP to MCL superimposed for each child participant in the study (up right) and to zero stimulus intensity (bottom right). On the left side of the graph, the average across all children CI users is shown for MCL and for the zero-stimulus intensity. As can be observed, compared to the eCAEP for MCL, the grand average response demonstrates obligatory auditory cortical components with N1-P2 complexes, which are not identifiable in the zero-intensity grand average. Table 1 details the minimum, maximum, mean and standard deviations of latencies and amplitudes of the eCAEPs components (P1,N1, P2) as recorded directly from the CI. A substantial variability in latencies and amplitudes of the eCAEP components is demonstrated between subjects. Table 1. Mean, standard deviations, minimum and maximum P1, N1 and P2 peak latencies and amplitudes of the eCAEP recorded in 20 CI children. Latencies (msec) Component Mean SD Minimum Maximum LP1 100.4 23.1 69 165 LN1 146.5 20.9 116 199 LP2 231.3 34.1 186 301 Amplitudes (µV) AP1 3.7 2.6 1 10.5 AN1 7.9 3.2 3.05 13.6 AP2 4.2 2.6 1.1 11.3 Figure 3 depicts the P1 peak latencies of all 20 children who participated in the study, displayed against P1 eCAEP norms for P1 peak latency of children 12 . The P1 latencies of 17 out of 20 children fall within normal limits (solid red circles). One child showed a P1 latency earlier than expected for their age (black solid circle), while two children exhibited P1 latencies longer than expected for their age (blue solid circles). eCAEP Repeatability and stimulus level effect To examine the repeatability of the eCAEP within and between sessions, Fig. 4 depicts the repeatability of two consecutive eCAEP tests, with short breaks in six children. The grand average of the first and second repetition of the 10 tested children is illustrated in the middle-bottom of the figure. As can be seen, the first and second repetition are highly correlated and Table 2 details the statistical analysis of the eCAEP repetition. Statistical analysis (ANOVA) for the latencies or the amplitudes of each eCAEP component revealed insignificant differences between the 1st and 2nd test (P1: F (1,9) = 0.87, p = 0.37; N1: F(1,9) = 1.23, p = 0.29; P2: F(1,9) = 0.56, p = 0.47). Furthermore, repeated correlation between the eCAEP of the first and second time resulted in significant (p < 0.01) coefficients of 0.94 for P1 latency, 0.89 for N1 latency and 0.7 for P2 latency. Similar significant (p < 0.01) correlations found for eCAEP amplitudes with 0.86,0.89 and 0.84 for the P1,N1 and P2 respectively. Table 2 Mean, standard deviation, minimum and maximum of the peak latency and amplitudes as measured in the first and the subsequent second test. No statistical differences were noted between the 1st and 2nd test. Latency’s Component (ms) 1st or 2nd Mean SD Minimum Maximum LP1 1st 89.7 19.8 58 119 2nd 93.6 18.1 60 122 LN1 1st 138.1 23.1 84 177 2nd 138.2 22.1 90 179 LP2 1st 245.1 37.1 188 317 2nd 245.6 38.8 194 330 Latency’s Amplitudes (µV) AP1 1st 5.25 3.3 1.95 10.9 2nd 5.23 3.1 2.2 11.2 AN1 1st 6.3 3.1 2.4 12.3 2nd 6.9 3.1 0.5 15.3 AP2 1st 4.9 2.1 1.1 8.3 2nd 4.5 2.5 1.4 9.7 Figure 5 demonstrates the test-retest repeatability of eCAEP in two children, both within and between different dates of testing sessions, with a gap of 2 or 6 months between them. It can be observed that repeatability is good not only within the same session but also in subsequent sessions conducted several months apart. Figure 6 illustrates the effect of stimulus intensity on eCAEP in 4 subjects. The highest intensity for each subject represents their comfortable level, with the remaining intensities being lower and weaker. It can be observed that a decrease in intensity sometimes affects both latencies and amplitudes, while in other instances, it only influences one of these parameters. Due to the limited number of children examined (6 children) and the absence of a standardized protocol for stimulus intensities, it was not possible to analyze this effect statistically. Table 3 details the effect of electrical stimulus intensity on the latencies and amplitudes of P1-P2 components of the eCAEP. Generally, as the intensity decreased, an increase in component latencies and a decrease in amplitude were observed for most components. Due to the small sample size of children, statistical tests (paired t-tests) were only performed for the Most Comfortable Level (MCL) and medium intensity levels. Significant differences were found in the latencies of P1 and N1 waves, while for wave amplitudes, a significant difference was only found in the AN1 component. Table 3 shows the effect of electrical stimulus intensity on the latencies and amplitudes of P1-P2 components of the eCAEP. Loudness MCL n=11 Moderate n=11 Soft n=6 P< CU Level 244.5±50.8 211.8±46.2 161±24.8 LP1 (ms) 92.6±18.3 103.7±19.7 112±11.3 0.04 LN1 (ms) 130.4±23.4 144.1±27.5 153.1±13.7 0.05 LP2 (ms) 207.5±38.1 220.4±46.4 252.3±26.5 NS AP1(µV) 4.45±3.6 3.5±2.5 4.6±2 NS AN1(µV) 9.4±8.3 6.6±5.5 8.9±4.5 0.05 AP2(µV) 4.9±2.7 4.5±2.5 3.3±1.4 NS Comparing scalp to CI recorded eCAEP To examine the similarity in waveform between the eCAEP recorded directly from the implant and that recorded via scalp electrodes, a comparison was made for latencies and amplitudes of the three eCAEP components, and by performing a cross correlation between the eCAEP waveshapes. Figure 7 illustrates the overlap of eCAEP from the CI versus scalp electrodes in 5 children. The lower middle part of the graph presents the grand average of 10 children for whom comparison between the two types of recordings was possible. While no differences were found between peak latencies, the intra cochlear eCAEP were significantly higher than the scalp recorded eCAEP. To examine the similarity of the paired participant waveforms, we again examined the scalp and CI eCAEP M-level waveforms using cross correlation in individual subjects. The maximum cross-correlations, with associated lag in parentheses, were: S15 = 0.70 (− 16 ms); S14 = 0.61 (6 ms); S18 = 0.48 (8 ms); S16 = 0.51 (31 ms); S10 = 0.70 (1 ms). From this, the mean cross-correlation in 10 individual children was 0.89 with a standard deviation of 0.19. The mean lag was − 0.29 ms, with a standard deviation of 25.42 ms. Note: a positive lag means that the maximum cross-correlation was achieved when the CI eCAEP waveform is shifted later in time, and a negative lag means that the maximum cross correlation was achieved when the CI eCAEP is shifted earlier in time in comparison to the scalp eCAEP waveform. Generally, it can be observed that while component latencies are similar, amplitudes in the implant recordings are higher than those from surface electrodes. Table 4 details the means, ranges, and standard deviations of latencies and amplitudes for each response component, as well as the correlation coefficients between the two types of recordings. An ANOVA test for differences in latencies of various components of the cortical response showed no significant differences between CI recordings and scalp electrode recordings. In contrast to latencies, amplitudes of each component P1 (ANOVA p < 0.03) N1 (p < 0.001), P2-(p < 0.001) were significantly larger in CI recordings relative to scalp recordings. The average amplitude of the P1 component in CI recordings was 2.6 times larger than that of scalp recordings, N1 was 4.2 times larger, and P2 was 3.6 times larger. The mean cross correlations across subjects between the two types of eCAEP were 0.5 (with mean lag of 6.3 msec), ranging from 0.18 (with lag of 15 msec) to 0.89 (with lag of 2 msec). Table 4 shows the means, ranges, and standard deviations of latencies and amplitudes for each response component, as well as the correlation coefficients between the two types of the recordings (CI and scalp). Latency’s Component (ms) Scalp or CI Mean SD Minimum Maximum LP1 Scalp 89.7 19.8 58 119 CI 93.6 18.1 60 122 LN1 Scalp 138.1 23.1 84 177 CI 138.5 22.1 90 179 LP2 Scalp 245.1 37.1 188 317 CI 246.3 38.8 194 330 Amplitude’s Components (µV) AP1 Scalp 1.9 3 0.03 9.8 CI 4.9 4.1 0.4 14.3 AN1 Scalp 2.4 2.1 0.01 5.4 CI 10.1 4.6 2.17 21.5 AP2 Scalp 1.5 2.1 0.01 5.9 CI 5.5 3.3 1.73 12.8 Point to Point Correlation Coefficients 0.5 0.27 0.18 0.89 Clinical Relevance: To demonstrate the possible association between auditory performance with CI and eCAEPs, Fig. 8 shows the grand average eCAEP of 13 pediatric participants with maximal 7th level of the CAP who were implanted at young age between 0.6 to 6.7 years and are currently 2.5 to 16.7 years old. Their average eCAEP response was compared to a group consisting of 7 children, implanted between 0.6 to 8.7 years after birth and currently ages between 4.1 to 16.6 years old. The eCAEP of the better performing group showed early P1 latency and higher eCAEP amplitudes as compared to the low performing CAP children. Figure 9 shows the box plot including the median and quartiles of P1 latency measured in the 13 participants with score of 7 in CAP compared to 7 children with CAP scores of 3,4 and 5 levels. ANOVA revealed that the latency of P1 was significantly shorter in the group with CAP 7 (89.3 ± 16.2 ms) than the group with poorer CAP scores (122.8 ± 23.6 ms). In average, N1 latencies were also shorter in the first (142.8 ± 20.4 ms) than the second group with low scores of CAPs, however it did not reach to a significant level. Regarding amplitudes, P1 (4.3 ± 2.9µV) and N1 (9 ± 3.6µV) were higher in the better CAP group, but reached to a significance different only in N1 (df (1,18) = 4.6,p = 0.04). Figure 10 illustrates the impact of cochlear implantation timing since the onset of deafness on eCAEP waveforms in two children with congenital hearing loss, currently aged 10 and 16 years, who were implanted at 10 and 15 months respectively (pre-lingual). Their eCAEP waveforms are compared to those of two adults with progressive hearing loss from birth, currently aged 29 and 48 years, who were implanted at 24 and 38 years (post-lingual). As observed, the pre-lingual children exhibit waveforms with shorter component latencies and larger amplitudes compared to the post-lingual adults. P1 latencies for the children were 75 and 91 ms, N1 were 149 and 154 ms, and P2 were 232 and 218 ms. In contrast, for the adults, P1 was recorded at latencies of 133 and 149 ms, N1 at 161 and 210 ms, and P2 at 228 and 262 ms. In pre-lingual children, component amplitudes ranged from 10 to 15 µV, while in adults, they were only 3 to 5 µV. Discussion This study aimed to investigate the feasibility and validation of electrical stimulation and recording of long-latency auditory evoked potentials (eCAEPs) directly from cochlear implant systems in a group of bilaterally implanted 20 children and 3 adults AB CI users. In this unique technique of recording, the implant systems effectively functioned as bidirectional wireless interfaces, enabling both stimulation and recording of the responses. To validate the compatibility of the cortical response pattern and its characteristics with standard EEG-derived responses, we conducted simultaneous direct recordings from the implant and scalp surface electrodes, processing the latter through a standard EP system. Additionally, to assess the reliability of the eCAEP, we examined response repeatability across two sets of consecutive stimuli within the same session and between sessions conducted months apart. We also demonstrated the effect of electrical stimulation intensity on the eCAEP to MCL, moderate softer and zero CU levels of electrical stimulation. Our findings demonstrate that eCAEP were successfully recorded from all pediatric and adults CI users with functional implants and with continuous use of the implant. No participants requested to discontinue the examination prematurely. The recording time for 150 stimuli was approximately 4 minutes, which is considered reasonable for clinical examination, even for young children. This suggests that the eCAEP recording procedure is well-tolerated and potentially suitable for routine clinical use. The eCAEP exhibited high test-retest reliability, demonstrating consistent waveform morphology and component characteristics both within individual sessions and across follow-up sessions conducted months apart. To quantify this reliability, we calculated the correlation coefficients for the latencies and amplitudes of the P1, N1, and P2 eCAEP components. The coefficients for latencies ranged from 0.7 (P2) to 0.94 (P1) and for amplitudes 0.84 (P2) to 0.89 (N1), indicating a strong to high level of reliability. Additionally, we performed repeated-measures ANOVA on these components, comparing data from the initial examination with those from follow-up sessions. Results revealed no statistically significant differences in any of the components. A similar high test-retest repeatability of eCAEPs recorded by AB CI system in adults was previously reported 46 . These findings provide strong evidence for the stability and reliability of eCAEP measured directly by the CI system over time, supporting their potential use in longitudinal clinical assessments of auditory cortical function in children and adults cochlear implant users. These findings also are in line with similar high test-retest reliability often seen in the CAEP recorded by scalp electrode in children and adults using CI or normal children 48 , 49 , 50 .‏ Bell-Souder et al. 46 demonstrated the feasibility of recording eCAEP using an intra-cochlear montage in 7 adult cochlear implant users. The study included participants aged 19 to 82 years, with six individuals implanted between 42 and 78 years of age, and one participant implanted at 9 years old. However, unlike the current study where P1 was identified in all participants, their research encountered difficulties in identifying P1 in 4 out of 7 subjects. This difference likely stems from the nature of stimuli used in both studies. In the current pediatric study, the stimulus was a 10 ms electrical pulse delivered to a single apical electrode (number 1). In contrast, the previous work used a 20 ms speech stimulus (/uh/) presented to the first 8 apical electrodes. This stimulus presumably elicited a larger artifact in the stimulating implant, which spread and was recorded in the contralateral recording implant, making it challenging to identify the response shortly after stimulus onset in some implanted subjects. In the current study, due to the nature of the stimulus, the artifact was smaller and ended before the onset of the P1 component. Nevertheless, mean P1-N1 wave latencies in adults were 36.6 ± 7.4 and 86.2 ± 9.7 ms, respectively. In addition, age is a factor, children have longer P1 latencies than adults, which makes it easier to identify beyond initial artifacts. The current study found mean P1-N1 latencies in children to be 100 ± 23.1 and 146 ± 21 ms, respectively. Differences in wave latencies between children and adults are expected given the variations in participant age and cortical maturation 27 , 51 . The P1 latency data from this study shows that 17 out of 20 children fall within the normal range for their age (Fig. 3 ). One child (S11), aged 5.9 years, exhibited earlier P1 latency than expected for their age. This child received bilateral simultaneous cochlear implants (CIs) at 8 months old and is a very good performer with CIs (CAP score 7; 100% speech intelligibility in quiet and 90% in noise). In contrast, two children (S8 and S9) showed late eCAEPs. They are currently 13.4 and 11.1 years old and were implanted at 0.9 and 8.7 years, respectively. Both are from the same signing family, attend educational frameworks for the deaf, and are considered poor performers with CIs (CAP scores 3 and 5; speech intelligibility less than 50% in quiet and less than 30% in noise). Further distinctions between early and late cochlear implantations has been shown between adult post lingual and children pre-lingual CI users. These cases illustrate the ability of the test to reflect, through the and prepattern but primarily through the P1-N1 latency components, the performance of implant recipients. This performance is influenced both by the timing of the implantation and by the necessity for continuous auditory input to achieve maximal neural plasticity in response to electrical stimuli. Our demonstrations with the intra-cochlear eCAEP are align with previously reported findings from scalp-recorded CAEPs in these groups 22 , 52 , 53 , 54 . These further reinforce the validity of using eCAEPs as a tool for evaluating auditory performance and highlight the necessity of further investigation and expansion of clinical applications utilizing eCAEPs. A requested aspect in validating and optimizing the use of cochlear implant (CI) systems for recording intracochlear brain potentials is comparing them to conventional scalp-recorded brain potentials. The current study has demonstrated the similarity between these two recording methods, particularly in terms of peaks latencies. The correlation coefficients between the individual scalp and the CI recorded eCAEP ranged between 0.18 to 0.89 with a mean of 0.5. ANOVA found no significant differences in the latencies of P1, N1, and P2 peaks between intracochlear CI recordings and scalp recordings. However, a notable distinction lies in the peak’s amplitudes. The eCAEP recorded by CI demonstrates significantly higher amplitudes compared to scalp-recorded potentials, with P1, N1, and P2 components showing 2.5, -3.6-, and 4.3-times greater amplitudes, respectively. These enhanced amplitudes can be attributed to both the properties of the recording electrodes, the differences in tissue conductivity and in the proximity to the eCAEP generators located in the brain. The montage of the CI recording array includes an active intracochlear electrode referenced to an electrode embedded subcutaneously in the temporal bone. This array is situated in a conductive medium with superior conductivity compared to the scalp recording array. The distance between the scalp and brain varies significantly with the age of the brain region. In newborns, the mean brain-scalp distance across the entire brain surface is approximately 5.9 ± 1.5 mm, increasing to about 10.1 ± 1.9 mm by age 7 55 and to 23.6 ± 0.7 mm un adults. The proximity of the CI electrodes to the auditory cortex in children, where CAEP generators are primarily located, allows for more direct recording of neural activity, improved signal-to-noise ratio, reduced interference from external noise and biological artifacts, leading to enhanced eCAEP amplitudes recorded compared to the scalp recorded. The larger eCAEP amplitudes recorded through CIs in children can significantly improve clinical applications of cortical potential, facilitating more precise assessment and monitoring of auditory function in pediatric CI recipients. These enhanced signals should offer more robust and sensitive measures of cortical responses, potentially enabling more accurate tracking of auditory development, neural plasticity, and rehabilitation progress. The increased amplitude could allow for more refined device programming and individualized intervention strategies, ultimately supporting more effective auditory rehabilitation in children with cochlear implants. However, since this is the first time such enhanced amplitudes have been observed in this context, further studies are needed to confirm these findings and fully elucidate their clinical implications. Additional research will be crucial to validate the reliability and clinical utility of these enhanced eCAEPs in pediatric CI users across different age groups and listening conditions. The significant enhancement of eCAEP amplitudes observed in this study is in line with the report on a similar trend of enhancement shown in 7 adult AB CI users 46 and in 2 adults subjects using eCAEP recordings through a percutaneous connector with an electrode array of Cz and intra cochlear basal electrode 41 . Additionally, the current study supports bigger amplitudes of the eCAEP recorded by an epidural electrode in 10 adult CI users 39 . Recording eCAEPs directly from the CI at MCL and lower stimulation levels offers the potential for objective assessments of cochlear implant users, particularly in children who are unable to provide reliable behavioral feedback. To date, such assessments have been performed using scalp surface electrodes, demonstrating efficacy in estimating hearing thresholds 31 , 47 , 56 , objectively identifying MCL levels 11 , 57 , aiding implant mapping 32 , 47 , 50 , 56 , 57 , 58 , and evaluating and improving auditory performance in pediatric implant users 59 . By enabling the recording of eCAEPs directly from the implant without requiring additional external equipment, these clinical applications can now be conducted more conveniently and efficiently in children within a clinical setting. However, before broad clinical implementation, and given the variability observed in the effects of stimulus intensity on eCAEPs in the 11 children in this study, further investigation is needed. Expanding the study to include a larger cohort of children and employing a standardized testing protocol across participants is essential to better understand and account for the influence of stimulus intensity on eCAEP characteristics. In conclusion, this study, conducted with a group of 20 children and 3 adult CI users, demonstrated the feasibility and potential clinical value of directly recording eCAEPs in response to electrical stimuli from the CI system. The findings showed good test-retest repeatability, high similarity to scalp-recorded CAEPs, and promising preliminary insights into the effects of electrical stimulus levels on eCAEP characteristics. The short test duration of less than 5 minutes further supports its practicality for clinical use. These results highlight the potential of eCAEP recordings as a valuable tool for assessing and monitoring auditory performance in children with CIs. Additionally, this study builds on previous findings that demonstrated the feasibility of recording CAEPs in response to acoustic stimuli in children and adults with residual hearing and to electrical stimuli in adults CI users 46 . Overall, these CI CAEP studies represent a significant advancement in expanding the range of available closed-loop objective measures in CI, beyond peripheral responses (e.g. Neural Response Imaging (NRI) and Electrically Evoked Cochleography (eCochG). By introducing a novel brain-based objective measure, they provide a new tool for evaluating and optimizing auditory performance without requiring active participation from patients, which is particularly beneficial for children. Methods Participants and ethics declarations In this study 20 children aged from 2.5 to 17 years and 3 adults 21, 28 and 48 years (13 females and 10 males) participated. All were bilateral AB CI users. All children had congenital severe to profound hearing loss and were implanted in both ears at young ages ranging from 7 months to 4 years from birth. The three adults were post-lingual implanted sequentially between 8 years to 25 years post hearing loss onset. Table 5 details the demographic data of each subject including, age of implantation, implant type and electrode type, etiology of deafness, and the Category of Auditory Performance (CAP) score. CAP is a standardized scale for assessing auditory outcomes in children with cochlear implants. The scale consists of eight performance categories arranged in ascending order of difficulty, from no awareness of environmental sounds (0 score) to the ability to use a telephone with a familiar speaker (7 score). The CAP scale evaluates children's daily auditory and verbal skills, reflecting their hearing improvement during follow-up sessions after cochlear implantation. The table also details the participants who, in addition to recordings of eCAEP to comfortable levels, took part in examining the influence of additional factors on the potential. These participants were selected due to their willingness, relatively older age, and tolerance for a longer research session. Subjects or their parents provided written informed consent to participate in the study, but they were free to stop their participation at any point during the study. The protocol of the study was approved by the Investigational Review Board (IRB:. 0617-19-RMC, Schneider Children Medical Center, Israel) and all methods were performed in accordance with the relevant guidelines and regulations. The current mean age of the CI children group was 11.09 ± 4.1 yrs with a minimum of 2.5 yrs and maximum of 16.7 yrs. The mean implantation age was 2.3 ± 2.3 yrs ranging from 0.6 to 8.7 post-natal years. All had congenital deafness with etiologies including genetic (11) Auditory Neuropathy (2), LVA (1), CMV (1) and the rest with unknown source (5). The current age of the three adults is 21,29 and 48 years, all had congenital deafness from unknown etiology and received CI at 2.4, 46 and 3 years respectively. In the children’s group CAP scores range between 7 (13 children) and 5(4). 4 (2) and 3 (1). The 3-adult scored 7 (1 adult) and 4 (2). Table 5 Age at the test, gender, age at CI, etiology of deafness, CI and electrode type, Category of Auditory Performance. In the last column, description of the subjects who participated in evaluations of: * eCAEP Repeatability; +Effect of stimulus level on eCAEP; X Comparison of eCAEP Scalp vs CI recordings. Subject # Age Now (yrs) Gender Implantation’s Age (yrs) Etiology Implant Type Right CI Electrode CAP Subjects used for the effects on eCAEP S1 12.3 M 1 Genetic Hires 90K MS 5 *X S2 9.3 F 2.9 Genetic Hires Ultra 3D SlimJ 7 * S3 7.3 M 0.6 Auditory Neuropathy Hires Ultra 3D SlimJ 7 S4 16.6 F 1 Genetic Hires 90K 1J 5 S5 2.5 F 0.7 Unknown Hires Ultra 3D SlimJ 7 * X S6 12.5 F 6.1 Genetic Hires 90K Advantage 1J 7 * +X S7 9.5 F 0.6 Genetic Hires 90K Advantage MS 4 + S8 13.4 M 8.7 Unknown Hires 90K 1J 3 * S9 11.1 F 0.9 Unknown Hires 90K Advantage MS 5 S10 6.3 F 1.7 Auditory Neuropathy Hires Ultra 3D SlimJ 7 X S11 6 M 0.7 Unknown Hires Ultra 3D SlimJ 7 S12 13.3 F 2.5 CMV Hires 90K Advantage MS 7 * X S13 12.5 M 6.6 Unknown Hires Ultra 3D SlimJ 7 * X S14 16.6 F 1.4 Genetic Hires 90K IJ 7 *+X S15 16.7 M 1.9 Genetic Hires 90K 1J 7 *+X S16 13.7 M 3 Genetic Hires 90K Advantage 1J 7 +X S17 12.9 F 1.1 LVA Hires 90K Advantage MS 7 S18 9.6 M 0.8 Genetic Hires 90K Advantage MS 7 *+ X S19 15.7 M 3.8 Genetic Hires 90K Advantage 1J 4 S20 4.1 M 0.6 Genetic Hires Ultra 3D SlimJ 5 S21 21.1 F 2.4 Unknown Hires Ultra 3D MS 7 S22 48.1 F 46 Unknown Hires Ultra SlimJ 4 S23 28.9 F 3 Unknown Hires 90K IJ 4 Test Set-Up and Recording Parameters In the current study, bilateral CIs were used such that one CI served as the electrical stimulator while the contralateral CI functioned as an EEG recording system. The Advanced Bionics (AB) system comprised the following components: the AB Clinical Programming Interface (CPI-3), which was connected to a PC on one end and to the second Naída CI Q90 speech processor on the other end. Each of the two speech processors was connected to an RF cable and headpiece for communication with the internal implant in each ear of the bilaterally implanted participants. The speech processors were also connected to a trigger dongle, which facilitated the delivery or reception of trigger signals. Only one speech processor functioned as the stimulating processor, delivering electrical stimuli to the corresponding ear. This stimulating processor, referred to as the ipsilateral processor, generated a trigger signal at the onset frame of the electrical stimulus, which was sent to the second processor, referred to as the contralateral processor. Simultaneously, the ipsilateral processor provided the same trigger signal to the "trigger in" port of a Biologic standard evoked potential (EP) system (Navigator-Pro Evoked Potential System, Bio-Logic Systems Corp., Mundelein, IL, USA). This later configuration allowed for the examination of the correlation between cortical auditory evoked potentials (eCAEP) recorded via the scalp (using the EP system) and those recorded via the contralateral CI. All eCAEP presented in this study were collected from the contralateral (non-stimulating) side. The electrical stimulus evoking eCAEP was a biphasic pulse train of 10 msec duration. Stimulus phase polarity is cathodic (negative phase first). The duration of each phase was set to 36 microsec. These parameters of the electrical stimulation were fixed and not change across all participants, unless the impedance values at the stimulating electrode is too high, which causes the stimulus to be out of compliance, then the phase duration was increased to higher value than 36 µs. The number of sweeps across all participants was 150 sweeps which took around 4 minutes for each experiment trial. Presentation level of the electrical stimulation was set based on the user feedback reported when reaching sound level of loud and comfortable. For Subjects that can’t provide any feedback, Presentation level was set based on daily map M levels at the stimulating electrode. The duration of each sweep will be explained in detail in a later section. For the purpose of this study, we used Advanced Bionics’ proprietary research software BEEP (Bionics Ear Evoked Potential, BEEP version 1.1.0.1) app for direct CI eCAEP recording. The BEEP app controlled the experimental CI setup and manipulation of all parameters mentioned previously and allowed synchronization and trigger communication between both processors, and between AB CI system and the standard EP recording system. Following the presentation of the electrical signal to the stimulated CI system, the standard EP system began the CAEP recording via the scalp electrodes, while the CI recorded eCAEP directly through intracochlear electrodes from the non-stimulating side. The BEEP App controlled the CPI-3, two Naida CI Q processors, and the implant through Advanced Bionics implant system. This software removed the necessity to concatenate smaller recording snippets to capture the whole eCAEP response, as done by previous studies e.g. 42 . This enabled recording for longer durations than the standard CI-related objective measures such as eCAP and ECochG. The electrical stimulus to the ipsilateral CI system was presented to the apical electrode number 1 while the eCAEP recording was done via the basal electrode 13. The recording electrode was chosen based on the low impedance level and sometimes based on the presence or absence of NRI responses at this electrode. If it was not possible to record from electrode 13 due to a technical reason, mainly high impedance value, then electrode 12 or 14 was chosen. The stimulating electrode reference was the ground electrode located in the CI housing, i.e. the case ground, and the recording electrode reference was the ground case electrode located at the lead of the electrode array as detailed in Fig. 11 . As shown in Fig. 11 , the recorded EEG via the implanted electrodes was collected back, by RF backward telemetry to the processor and then to BEEP App for visualization and signal processing. Simultaneously, the CAEP recorded by the scalp montage (Fz-Mastoid) and collected for signal processing by the external EP system. In this study, the single-channel CI eCAEP was compared with the most common single-channel scalp recording (Fz-Mastoid) as described by (Lightfoot & Kennedy 2006). The gain of the internal differential amplifier of the AB implants was fixed and set to 1000, and its output was sampled at a frequency of 1000 Hz. The low pass cut-off frequency was set at 5 kHz. Data collection technique: As detailed in Fig. 12 , each CI eCAEP measurement “sweep” consisted of two parts. The first one is the “null” part, which presents a zero-amplitude stimulation followed by a recording window with a duration of 500 msec. The duration of the recording window is set within the BEEP app. The second part is the “stim” part, which presents an MCL amplitude stimulation followed by a recording window with a duration of 500 msec (same length as the “stim”). Each CI eCAEP run consisted of 150 sweeps. For testing repeatability of the e-ACEP, two consecutive trials at the MCL level were conducted. The standard EP system recorded the eCAEP via scalp electrodes receiving trigger concurrent to the presentation of the electrical stimulus at the ipsilateral side, and the start of e-CAEP recordings via the contra lateral CI system. For the standard EP system, the active electrode was attached to the forehead, the reference electrode to the mastoid or the lobule with the contra lateral CI, and the ground electrode to the mastoid or lobule of the stimulated CI side. A filter device was placed between the patient and the EP system to eliminate any RF artifacts using a 34 kHz low pass filter. The EEG activity was bandpass filtered from 1 (12 dB/octave) to 100 Hz. A notch filter was also used to remove the power line frequency noise. The EEG activity was then amplified by 50,000 and sampled in a window of 533 ms (512 data points per sweep at a sampling rate of 1,000 Hz). Testing was performed in a standard sound booth and participants were seated in a recliner chair. Participants and/or guardians were given a full explanation of the procedure before starting measurements. The external scalp electrode impedance was kept less than 3 KΩ to decrease any external noise because of high impedances. CI impedance levels for the implanted electrode array were all measured to be within normal limits (between 1 and 30 kΩ as per clinical guidelines). The ideal value of the impedance for the recording electrode was chosen to be less than 10 KΩ if feasible. Adult participants and the teenager participant were asked to count the electrical stimuli during testing while the children under 6 years old were offered a tablet with a muted video during testing, to keep the participants awake and alert to minimize eye-blink artifacts, and to minimize hand or finger movements. Participants were able to take a short break between recording sessions. Data Analysis The collected CI CAEP data was post processed in an additional Matlab app that was developed for this purpose. As mentioned before, each recorded data set contained 150 measurement sweeps. All data points of the standard scalp electrode CAEP were inverted in polarity (negative sign) before further processing to match the recording montage of the CI eCAEP (intracochlear electrode #13 referred to the case). For each measurement trial, the “null” sweeps were subtracted from the “stim” sweeps. The sweeps then were averaged, linear data trend was removed, then filtered by a second-order infinite impulse response filter (IIR filter) with a bandpass of 1 Hz and 20 Hz followed by the application of a moving average technique with a time window of 33 msec. There were two main limitations faced during the research when recording cortical responses from the CI system. The first one is the recording artifact or recording noise, which presents the electrical circuit behavior, and it is present whenever the implant initializes a recording window and starts recording the cortical response. This noise is present in both, the ipsilateral side and the contralateral side implants, and also during zero stimulation (“null” stage) and high amplitude stimulation (“stim” stage). To resolve the recording artifact, subtracting the “null” from “stim” technique was used. During the recording of the “null” stage, which is preceded by the 10 msec duration of zero amplitude stimulus, the recording object will apparently record no cortical response and no stimulus artifact as there was no stimulus present prior to it. The only data that will be recorded is the circuit behavior, which is assumably the same for that specific recording trial. For the “stim” stage, which is preceded by the 10 msec duration of MCL amplitude stimulus, the recording object will record the cortical response, the stimulus artifact and the noise of the circuit behavior. The noise of the circuit behavior is considered to be the same as for the “stim” stage and can be subtracted from it and eliminated. The second limitation is the electrical stimulus artifact. The greater the amplitude of the stimulus, the greater the artifact. In order to avoid the stimulation artifact, the cortical responses were reported only from the contralateral side (the non-stimulating side), and the recording from the ipsilateral side was ignored. Combining the two solutions will lead to the conclusion to record the responses from the contralateral side using the subtraction of the “null” stage from the “stim” method. In the process of collecting the data from the ipsilateral side, i.e. stimulating and recording on the same side, the presence of stimulation will cause the presence of its artifact, which can be significant at high stimulation amplitudes. On the other hand, the process of collecting the data from the contralateral side, i.e. stimulation on one ear and recording the response from the other ear, as shown in Fig. 13 , the stimulation artifact is not present in the contralateral ear. Therefore: Following offline analysis, author JA, blinded to the recording method (cochlear implant or scalp recording), manually identified the peak latencies of the P1, N1, P2, and N2 components. The identification process was guided by previous reports on scalp-recorded eCAEP in normal-hearing individuals and pediatric cochlear implant users 8 , 37 . For the eCAEP in children, P1 was defined as the most prominent positive peak occurring between 55 ms and the subsequent largest negative peak (N1) within 200 ms after stimulus onset. P2 was identified as the largest positive peak following N1, occurring up to approximately 280 ms, while N2 was marked as the subsequent negative peak following P2, occurring within 370 ms post-stimulus. In addition, peak-to-peak amplitudes were calculated for P1 (P1-N1), N1 (N1-P2), and P2 (P2-N2) components. Statistical Analysis Statistical analyses were conducted using SPSS software (version 25; SPSS Inc., Chicago, IL, USA). Descriptive statistics were utilized to summarize data, including mean, minimum, maximum, and standard deviation values for the latencies and amplitudes of the P1, N1, and P2 eCAEP components. These metrics were also detailed for the most comfortable listening (MCL) levels, responses at softer amplitudes, repeated measurements, and comparisons between scalp-recorded and cochlear implant (CI)-recorded eCAEP. Repeated measures ANOVA was employed to evaluate test-retest reliability, as well as the effects of stimulation level and recording method on eCAEP metrics. Pearson correlation analysis was performed to assess the relationship between eCAEPs recorded via scalp and CI methods. Statistical significance was defined as a p-value of less than 0.05. Deidentified versions of the datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request. Declarations Competing interests Author Suhail HabibAllah is a current employee of Advanced Bionics, Israel. Author Chen Chen is a current employee of Advanced Bionics, USA. Author Joseph Attias declares no potential conflict of interest. Author Contribution Concept: S. H., J. A., C. C; Design: S.H, C.C; Data acquisition: S.H, J.A.; Analysis and interpretation: S.H, J.A., C.C; writing: J.A., S.H., C.C.; Suhail HabibAllah and Joseph Attias are considered as equal contributors in writing the article. Acknowledgement The authors extend their gratitude to Kanth Koka, PhD, for his valuable and insightful feedback on the research setup and an earlier draft of this article. They also wish to express their heartfelt thanks to the study's participants and their parents for their cooperation and support. Data Availability The data supporting this study will be made available upon reasonable request in an anonymized format. The request should be addressed to [email protected] . 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Journal of the Association for Research in Otolaryngology, 22(6), 719-740 (2021). Beauchamp, M. S., Beurlot, M. R., Fava, E., Nath, A. R., Parikh, N. A., Saad, Z. S., Bortfeld, H., & Oghalai, J. S. The developmental trajectory of brain-scalp distance from birth through childhood: Implications for functional neuroimaging. PLoS One, 6(9), e24981 (2011). Visram, A. S., Innes-Brown, H., El-Deredy, W., & McKay, C. M. Cortical auditory evoked potentials as an objective measure of behavioral thresholds in cochlear implant users. Hearing Research, 327, 35-42 (2015). Távora-Vieira, D., & Ffoulkes, E. Direct elicitation of cortical auditory evoked potentials by electrical stimulation and their use to verify the most comfortable level of stimulation in cochlear implant users. Audiology and Neurotology, 28(4), 294-307 (2023). Tremblay, K. L., Friesen, L., Martin, B. A., & Wright, R. Test-retest reliability of cortical evoked potentials using naturally produced speech sounds. Ear and Hearing, 24(3), 225-232 (2003). Távora-Vieira, D., Wedekind, A., Ffoulkes, E., Voola, M., & Marino, R. Cortical auditory evoked potential in cochlear implant users: An objective method to improve speech perception. PLOS ONE, 17(10), e0274643 (2022). Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 02 Jul, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 09 Apr, 2025 Reviews received at journal 07 Apr, 2025 Reviews received at journal 01 Apr, 2025 Reviewers agreed at journal 24 Mar, 2025 Reviewers agreed at journal 21 Mar, 2025 Reviewers invited by journal 18 Mar, 2025 Editor assigned by journal 18 Mar, 2025 Editor invited by journal 17 Mar, 2025 Submission checks completed at journal 17 Mar, 2025 First submitted to journal 06 Mar, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6170473","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":433020016,"identity":"2bc380d0-79ba-43dc-8324-2dac20665257","order_by":0,"name":"Suhail HabibAllah","email":"","orcid":"","institution":"University of Haifa","correspondingAuthor":false,"prefix":"","firstName":"Suhail","middleName":"","lastName":"HabibAllah","suffix":""},{"id":433020017,"identity":"e7c62caa-2db1-4ef6-8589-5aadd10e48f6","order_by":1,"name":"Chen Chen","email":"","orcid":"","institution":"Advanced Bionics","correspondingAuthor":false,"prefix":"","firstName":"Chen","middleName":"","lastName":"Chen","suffix":""},{"id":433020018,"identity":"46387c55-ffdf-44d9-afde-6d565ba6f073","order_by":2,"name":"Joseph Attias","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABCElEQVRIie3QMUsDMRQH8PcItMvDrieW9ivc0UUX+1USbripu6CckUK6HHY9v8WNjicHdhFcD3SI9AvYRQ4E8fV6iktudsifEBLCj38SAB+ffxjUPEmASbvkQUPdHgRjNxGomcx+CZUHQu4e0RYp/dPZEXASsXreWHuVJsXL0gR4fz6mYYnvDZw6CWYxX+yxWhSvD0yeYiKS4jjruRjqPRmUi6JWyxCNoDn/xknfW3C9ZfKVJuGBXBONrPjsJTm3KCMkkxuLpiIK5KC/Jd9Gubqtors9UWbD5M2cZaGbRGtld81HOj2qE1vuzOWcRnFVNxfpxEn0353svgQgdAGAqfvIx8fHx6fLN4qtUuNOGYDbAAAAAElFTkSuQmCC","orcid":"","institution":"University of Haifa","correspondingAuthor":true,"prefix":"","firstName":"Joseph","middleName":"","lastName":"Attias","suffix":""}],"badges":[],"createdAt":"2025-03-06 12:23:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6170473/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6170473/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-06652-z","type":"published","date":"2025-07-02T15:57:50+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":79345414,"identity":"0c123091-2bb1-4a21-bde7-4822de01d4b1","added_by":"auto","created_at":"2025-03-27 09:28:42","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":550565,"visible":true,"origin":"","legend":"\u003cp\u003eExamples of eCAEP responses from 9 CI children. Responses were collected using the BEEP app. Each graph shows P1, N1, P2 components and is labeled with subject number (see Table 1).\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/aee1b493071c20f9a72121fb.png"},{"id":79345412,"identity":"097d7847-7d18-4806-8b51-e21f4fae8bbe","added_by":"auto","created_at":"2025-03-27 09:28:42","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":601056,"visible":true,"origin":"","legend":"\u003cp\u003eIndividual eCAEP for MCL and zero-intensity levels superimposed with the grand average (left side) of all 20 CI children.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/32477b4c8f1796d594a0e93c.png"},{"id":79344210,"identity":"70bbf355-ef35-4f24-83ab-349c92f16a07","added_by":"auto","created_at":"2025-03-27 09:20:42","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":228815,"visible":true,"origin":"","legend":"\u003cp\u003eP1 peak latencies of all 20 pediatric CI recipients in this study. Seventeen falls within normal range (red solid circles), one child showed early P1 latency (black solid circle) and the other two children longer P1 latencies (blue solid circles) as expected to their ages.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/23ea394213f9585a73e62a7c.png"},{"id":79344212,"identity":"86f439fd-e0d3-47fb-ac2a-716ac51b000f","added_by":"auto","created_at":"2025-03-27 09:20:42","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":533703,"visible":true,"origin":"","legend":"\u003cp\u003eRepeatability of eCAEP responses as in 6 individual children. The grand average recorded across 10 children is displayed in the mid of the figure. No statistical differences were found between the first and second eCAEP test.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/ad09e0de29df48de2bf0f7b5.png"},{"id":79345819,"identity":"251983ca-7564-4218-bc62-d1e5ca4483ba","added_by":"auto","created_at":"2025-03-27 09:36:42","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":327063,"visible":true,"origin":"","legend":"\u003cp\u003eTest-retest repeatability within and between test sessions of eCAEP in two children with gap of number of months between them.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/7f4b28c17920819a0f015a10.png"},{"id":79344215,"identity":"ec67a5ff-837e-4289-8213-9dd49ac01a0c","added_by":"auto","created_at":"2025-03-27 09:20:42","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":658401,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of stimulus level on eCAEP recorded directly from the CI of 6 children.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/a7e24d9f669c14ce89f74a5b.png"},{"id":79344232,"identity":"c0ffbcea-26d6-4b37-957b-4f7dd316e27f","added_by":"auto","created_at":"2025-03-27 09:20:42","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":477355,"visible":true,"origin":"","legend":"\u003cp\u003eComparison between the eCAEP as recorded via the CI and to the eCAEP recorded through scalp recorded electrodes and EEG system.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/0a8c1313f863f268beaa188e.png"},{"id":79344218,"identity":"942bf412-38ce-4f44-b4b3-67bc736f6a1d","added_by":"auto","created_at":"2025-03-27 09:20:42","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":94695,"visible":true,"origin":"","legend":"\u003cp\u003eGrand average of eCAEP of children with maximal score of CAP superimposed on eCAEP of children with poorer CAP score.\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/3d29f5deba7b596ac3fd0b5e.png"},{"id":79345417,"identity":"1ed39fdc-959f-4568-9f45-99a7c22a17e9","added_by":"auto","created_at":"2025-03-27 09:28:42","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":50611,"visible":true,"origin":"","legend":"\u003cp\u003eBox plot of the P1 peak latency in children with CAP score of 7 against a group of children using CI with poorer CAP score.\u003c/p\u003e","description":"","filename":"floatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/f0f3f892284fa94afa005b5c.png"},{"id":79345421,"identity":"f059d317-19d5-46f1-8929-3b898d0de72e","added_by":"auto","created_at":"2025-03-27 09:28:42","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":359121,"visible":true,"origin":"","legend":"\u003cp\u003eAn example of eCAEP of a pre-lingual children received CI early in life compared to two adults implanted at adults ages, post-lingual.\u003c/p\u003e","description":"","filename":"floatimage10.png","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/96c76881e5dee03ccb5bdb95.png"},{"id":79345821,"identity":"04dc392a-a3c5-4556-b40b-c09dcfc8aaad","added_by":"auto","created_at":"2025-03-27 09:36:42","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":163712,"visible":true,"origin":"","legend":"\u003cp\u003eShows the set up for Bilateral e-CAEP test configuration from the implant and the recording set up from a standard EP system. The red arrows indicate signals or data going in the software for processing, and the blue arrow indicate signals or data going out from the software.\u003c/p\u003e","description":"","filename":"floatimage11.png","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/775acd00f7e55ae69c67ce07.png"},{"id":79344235,"identity":"b76e6e77-b682-4949-8474-9cce64e817b7","added_by":"auto","created_at":"2025-03-27 09:20:42","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":152077,"visible":true,"origin":"","legend":"\u003cp\u003eShows the Sweep structure in each experimental trail. Each sweep contained to stages, the “null” stage where no stimulus was presented, and the “stim” stage where stimulus was presented.\u003c/p\u003e","description":"","filename":"floatimage12.png","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/a1a9096a6d7a7855752aca62.png"},{"id":79346813,"identity":"7c4edcb6-8893-48f7-8de8-12f2b1e4281b","added_by":"auto","created_at":"2025-03-27 09:44:42","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":74462,"visible":true,"origin":"","legend":"\u003cp\u003eIllustrates the recording sequence as used in BEEP software, and its anticipated response for contralateral side (the recording and not stimulating side),\u003c/p\u003e","description":"","filename":"floatimage13.png","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/7415cce7eec9f6019f230976.png"},{"id":86180147,"identity":"c03fd2fa-6302-4c32-a46d-c2c026385182","added_by":"auto","created_at":"2025-07-07 16:21:23","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5322740,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6170473/v1/4cf5bc09-287f-40e4-95e9-a55bd0ebf3dd.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Electrically evoked cortical potentials recorded directly from cochlear implant system: Feasibility in pediatric users and clinical relevance","fulltext":[{"header":"Introduction","content":"\u003cp\u003eBrain plasticity plays a crucial role in optimizing outcomes for children with congenital hearing loss who receive cochlear implants (CIs) \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. During critical developmental periods, the brain's auditory pathways demonstrate remarkable adaptability, allowing them to reorganize and process new auditory signals provided by the CI \u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. This neuroplasticity facilitates the development of age-appropriate speech and language skills, particularly when implantation for congenital hearing loss occurs early in life \u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. Delayed implantation can result in cross-modal plasticity, where the auditory cortex is repurposed for other sensory modalities such as vision, potentially impeding auditory rehabilitation \u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. Early intervention mitigates these effects and maximizes the restoration of auditory cortical function, leading to improved long-term language and social outcomes \u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eNeuroimaging noninvasive techniques, such as functional MRI (fMRI) and diffusion tensor imaging (DTI), have been instrumental in demonstrating brain plasticity in cochlear implant (CI) users. \u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e,\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. Positron Emission Tomography (PET) is an additional neuroimaging technique using a radioactive tracer to demonstrate metabolic auditory brain activity following cochlear implant \u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e,\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. All those techniques have excellent spatial resolution revealing changes in neuronal activity, in connectivity tracts and white matter within the auditory cortex post-implantation, with a gradual normalization reflecting restored auditory function. However, they are limited by their low temporal resolution, high cost, the need for radioactive tracers, and unfriendly and challenging test-environments, making it less feasible for use in young children or routine clinical settings. Functional near-infrared spectroscopy (fNIRS) on the other hand, is a non-invasive and more accessible alternative that measures changes in oxygenated blood flow in the brain, providing real-time data with moderate spatial resolution. It has been used to monitor brain activity during auditory tasks in CI users, and studies have shown that it can detect functional changes in the auditory cortex post-implantation \u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e,\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. However, the relatively low temporal resolution, the need to place a cap with multiple source and detectors on the scalp and the necessity to avoid head movements, all making this technique limited for working with young children.\u003c/p\u003e \u003cp\u003eElectrophysiological techniques, particularly cortical auditory evoked potentials (CAEPs), are valuable tools for assessing brain plasticity after cochlear implantation, especially in young children where behavioral measures and subjective feedback are limited.\u003c/p\u003e \u003cp\u003eThese non-invasive measures offer excellent temporal resolution and provide objective insights into auditory cortical development and adaptation to electrical stimulation \u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e,\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e,\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e,\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e. Scalp recorded P1 component of CAEPs serves as a biomarker for central auditory maturation, allowing researchers and clinicians to track changes in neural responses over time \u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e,\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e,\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e,\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e,\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. In children with hearing loss, the P1 latency typically shows age-related decreases and morphological changes, reflecting the development of auditory cortical pathways \u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e,\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e,\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e,\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e. Studies have shown that children who receive cochlear implants before the age of 3.5 years often exhibit normal development of P1 latencies, even if these were initially delayed \u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. By providing an objective measure of auditory cortical development, the P1 CAEP aids in evaluating the success of early intervention and clinical management in pediatric cochlear implant recipients \u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eHowever, clinical implementation of scalp recorded CAEPs faces significant challenges in pediatric populations. Key limitations include complex electrode attachment, specialized equipment requirements, and the need for subject immobility during recording. These factors make the examination difficult for young children, who may find it challenging to maintain prolonged cooperation. Consequently, there is a need for more child-friendly approaches to neurophysiological auditory evaluation. By overcoming the practical constraints of traditional CAEP recordings, the ability to record the P1 potential directly from the cochlear implant (CI) system, without the need for external equipment provides a child-friendly solution for neurophysiological auditory evaluation.\u003c/p\u003e \u003cp\u003eIn the past, different intra cranial or intra cochlear approaches to record in adults CI users eCAEPs using an external EEG system for analysis, have been demonstrated. This included invasive recording technique by means of temporary implantation of a special epidural electrodes \u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e, or by using an electrode grid, implanted contralateral to the stimulus side in the course of an epilepsy surgery \u003csup\u003e\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e or by means of implanted a connector percutaneous attached directly to an external EEG recording system, in numerous adult CI users \u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e. Although these studies provided important insights regarding the significance of intra-cranial or cochlear recordings in improving the quality and amplitude of responses, they cannot serve as a clinical tool for standard monitoring and implementation in implant recipients, neither in adults nor especially in children. To circumvent the invasive approach, methods were proposed based on closed-loop systems for recording and processing cortical responses using electrodes implanted both within and outside the cochlea, as well as utilizing the speech CI processor of the cochlear implant \u003csup\u003e\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e,\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e. Both studies used the CI Nucleus 24, Cochlear Corp., Sydney, Australia and external EP system for off analysis. Due to severe memory limitations for recording long latency brain responses, which require sampling over extended time windows, researchers were compelled to use shorter sampling windows designed for short latency auditory nerve responses. These shorter windows were then concatenated to achieve cortical responses within approximately 300 ms windows. Although these methods demonstrated cortical responses that aligned with those obtained through standard techniques, the concatenation process resulted in significantly prolonged testing durations. Furthermore, substantial hardware and software modifications to the implant systems were necessary, greatly limiting their clinical applicability, particularly in adults and even more so in children.\u003c/p\u003e \u003cp\u003eAttias et al.\u003csup\u003e\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e were the first to demonstrate the feasibility and validation of direct recording of CAEP in long time window of 0.6 second post stimuli in bimodal children and adults using Advanced Bionics cochlear implants. In this approach, acoustic stimuli were presented in the ear with residual hearing triggering the contralateral ear with AB CI system to directly record CAEP response. The acoustic CAEP responses highly correlated with the traditional scalp recorded CAEP by an external EEG system. The duration of the test for 120 stimuli lasted approximately 3 minutes and was tolerated by all subjects.\u003c/p\u003e \u003cp\u003eUsing a similar intra-cochlear montage (apical and case electrodes) and the built-in backward telemetry of AB system, combined with an external EEG system, \u003csup\u003e\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e\u003c/sup\u003e demonstrated the feasibility of recording ACEP in five bimodal adult CI users. In two of these CI users, presenting attending and un-attending acoustic stimuli to the acoustic ear, showed the potential use of ACEP for decoding auditory selective attention.\u003c/p\u003e \u003cp\u003eRecently, \u003csup\u003e\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e\u003c/sup\u003e further showed the feasibility of direct recording of CAEP by the AB CI system in responses to speech electrical stimuli in 7 adult CI users. The CI recorded eCAEP responses well correlated with the scalp CAEP responses triggered by the stimulating CI system and recorded through external standard EP system.\u003c/p\u003e \u003cp\u003eThis study aimed to validate and demonstrate the feasibility of electrically stimulated and directly recorded intracochlear auditory cortical evoked potentials (eCAEPs) using the Advanced Bionics cochlear implant system in a group of 20 children (ages 4\u0026ndash;17) and 3 adults (ages 21\u0026ndash;28). The research focused on examining the repeatability of eCAEPs within and between testing sessions, as well as comparing the waveforms of intra cochlear eCAEPs with simultaneously recorded standard scalp evoked potential. Additionally, the study conducted a preliminary analysis of the relationship between eCAEPs and the electrical level stimulation, the age at implantation, as well as their association with speech and auditory outcomes. This comprehensive approach aimed to provide insights into the reliability and potential clinical applications of eCAEP measurements in pediatric cochlear implant recipients.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eThe application of the recording of cortical recordings directly by the CI system in 20 children and the 3 adults, revealed that eCAEP could be recorded from each functional CIs of the participants. All the subjects tolerated the testing well, and no one requested to end the testing before completion. The recording procedure took approximately 4 minutes for each run of 150 electrical stimuli. The eCAEP of each participant was evaluated and the peaks were identified by the first and last authors of the study, who are experienced on evoked potentials (SH and JA). Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e illustrates the eCAEPs recorded from 9 CI users out of 20 children who participated in the study. The decision to present data from 9 children was due to space limitations and the aim to provide representative examples. These cases illustrate the range of responses observed, with additional eCAEPs from other participants shown later in the study. The eCAEP\u0026rsquo;s components (P1,N1, P2 and N2) of the eCAEP were identified and marked for each study participant. As can be visually observed from the figure there is considerable variability in the latencies and amplitudes of the components among the subjects. In some cases, the P1 component (S9; S15) and the P2 (S3;S5).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e presents the variability in individual eCAEP to MCL superimposed for each child participant in the study (up right) and to zero stimulus intensity (bottom right). On the left side of the graph, the average across all children CI users is shown for MCL and for the zero-stimulus intensity. As can be observed, compared to the eCAEP for MCL, the grand average response demonstrates obligatory auditory cortical components with N1-P2 complexes, which are not identifiable in the zero-intensity grand average.\u003c/p\u003e \u003cp\u003eTable 1 details the minimum, maximum, mean and standard deviations of latencies and amplitudes of the eCAEPs components (P1,N1, P2) as recorded directly from the CI. \u0026nbsp;A substantial variability in latencies and amplitudes of the eCAEP components is demonstrated between subjects. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 1. Mean, standard deviations, minimum \u0026nbsp;and maximum P1, N1 and P2 peak latencies and amplitudes of the eCAEP recorded in 20 CI children. \u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"9\" valign=\"top\"\u003e\n \u003cp\u003eLatencies (msec)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eComponent\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003eSD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003eMinimum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMaximum\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLP1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e100.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e165\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLN1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e146.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e20.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e116\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e199\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLP2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e231.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e34.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e186\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e301\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"9\" valign=\"top\"\u003e\n \u003cp\u003eAmplitudes (\u0026micro;V)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAP1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e2.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e10.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAN1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e3.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e13.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAP2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e2.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e11.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e depicts the P1 peak latencies of all 20 children who participated in the study, displayed against P1 eCAEP norms for P1 peak latency of children \u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. The P1 latencies of 17 out of 20 children fall within normal limits (solid red circles). One child showed a P1 latency earlier than expected for their age (black solid circle), while two children exhibited P1 latencies longer than expected for their age (blue solid circles).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eeCAEP Repeatability and stimulus level effect\u003c/h2\u003e \u003cp\u003eTo examine the repeatability of the eCAEP within and between sessions, Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e depicts the repeatability of two consecutive eCAEP tests, with short breaks in six children. The grand average of the first and second repetition of the 10 tested children is illustrated in the middle-bottom of the figure. As can be seen, the first and second repetition are highly correlated and Table \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e details the statistical analysis of the eCAEP repetition. Statistical analysis (ANOVA) for the latencies or the amplitudes of each eCAEP component revealed insignificant differences between the 1st and 2nd test (P1: F (1,9)\u0026thinsp;=\u0026thinsp;0.87, p\u0026thinsp;=\u0026thinsp;0.37; N1: F(1,9)\u0026thinsp;=\u0026thinsp;1.23, p\u0026thinsp;=\u0026thinsp;0.29; P2: F(1,9)\u0026thinsp;=\u0026thinsp;0.56, p\u0026thinsp;=\u0026thinsp;0.47). Furthermore, repeated correlation between the eCAEP of the first and second time resulted in significant (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01) coefficients of 0.94 for P1 latency, 0.89 for N1 latency and 0.7 for P2 latency. Similar significant (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01) correlations found for eCAEP amplitudes with 0.86,0.89 and 0.84 for the P1,N1 and P2 respectively.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMean, standard deviation, minimum and maximum of the peak latency and amplitudes as measured in the first and the subsequent second test. No statistical differences were noted between the 1st and 2nd test.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLatency\u0026rsquo;s Component (ms)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1st or 2nd\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMinimum\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eMaximum\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eLP1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1st\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e89.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e119\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2nd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e93.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e122\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eLN1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1st\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e138.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e177\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2nd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e138.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e22.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e179\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eLP2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1st\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e245.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e37.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e188\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e317\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2nd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e245.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e38.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e194\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e330\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003eLatency\u0026rsquo;s Amplitudes (\u0026micro;V)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAP1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1st\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e10.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2nd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e11.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAN1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1st\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e12.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2nd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e15.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAP2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1st\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e8.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2nd\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e9.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e demonstrates the test-retest repeatability of eCAEP in two children, both within and between different dates of testing sessions, with a gap of 2 or 6 months between them. It can be observed that repeatability is good not only within the same session but also in subsequent sessions conducted several months apart.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e illustrates the effect of stimulus intensity on eCAEP in 4 subjects. The highest intensity for each subject represents their comfortable level, with the remaining intensities being lower and weaker. It can be observed that a decrease in intensity sometimes affects both latencies and amplitudes, while in other instances, it only influences one of these parameters. Due to the limited number of children examined (6 children) and the absence of a standardized protocol for stimulus intensities, it was not possible to analyze this effect statistically.\u003c/p\u003e \u003cp\u003eTable 3 details the effect of electrical stimulus intensity on the latencies and amplitudes of P1-P2 components of the eCAEP. Generally, as the intensity decreased, an increase in component latencies and a decrease in amplitude were observed for most components. Due to the small sample size of children, statistical tests (paired t-tests) were only performed for the Most Comfortable Level (MCL) and medium intensity levels. Significant differences were found in the latencies of P1 and N1 waves, while for wave amplitudes, a significant difference was only found in the AN1 component.\u003c/p\u003e\n\u003cp\u003eTable 3 shows the effect of electrical stimulus intensity on the latencies and amplitudes of P1-P2 components of the eCAEP.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003eLoudness\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003eMCL n=11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003eModerate n=11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003eSoft n=6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 124px;\"\u003e\n \u003cp\u003eP\u0026lt;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003eCU Level\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e244.5\u0026plusmn;50.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e211.8\u0026plusmn;46.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e161\u0026plusmn;24.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 124px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003eLP1 (ms)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e92.6\u0026plusmn;18.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e103.7\u0026plusmn;19.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e112\u0026plusmn;11.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 124px;\"\u003e\n \u003cp\u003e0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003eLN1 (ms)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e130.4\u0026plusmn;23.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e144.1\u0026plusmn;27.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e153.1\u0026plusmn;13.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 124px;\"\u003e\n \u003cp\u003e0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003eLP2 \u0026nbsp;(ms)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e207.5\u0026plusmn;38.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e220.4\u0026plusmn;46.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e252.3\u0026plusmn;26.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 124px;\"\u003e\n \u003cp\u003eNS\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003eAP1(\u0026micro;V)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e4.45\u0026plusmn;3.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e3.5\u0026plusmn;2.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e4.6\u0026plusmn;2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 124px;\"\u003e\n \u003cp\u003eNS\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003eAN1(\u0026micro;V)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e9.4\u0026plusmn;8.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e6.6\u0026plusmn;5.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e8.9\u0026plusmn;4.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 124px;\"\u003e\n \u003cp\u003e0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003eAP2(\u0026micro;V)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e4.9\u0026plusmn;2.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e4.5\u0026plusmn;2.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 125px;\"\u003e\n \u003cp\u003e3.3\u0026plusmn;1.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 124px;\"\u003e\n \u003cp\u003eNS\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\u003c/div\u003e\n\u003ch3\u003eComparing scalp to CI recorded eCAEP\u003c/h3\u003e\n\u003cp\u003eTo examine the similarity in waveform between the eCAEP recorded directly from the implant and that recorded via scalp electrodes, a comparison was made for latencies and amplitudes of the three eCAEP components, and by performing a cross correlation between the eCAEP waveshapes. Figure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e illustrates the overlap of eCAEP from the CI versus scalp electrodes in 5 children. The lower middle part of the graph presents the grand average of 10 children for whom comparison between the two types of recordings was possible.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eWhile no differences were found between peak latencies, the intra cochlear eCAEP were significantly higher than the scalp recorded eCAEP.\u003c/p\u003e \u003cp\u003eTo examine the similarity of the paired participant waveforms, we again examined the scalp and CI eCAEP M-level waveforms using cross correlation in individual subjects. The maximum cross-correlations, with associated lag in parentheses, were: S15\u0026thinsp;=\u0026thinsp;0.70 (\u0026minus;\u0026thinsp;16 ms); S14\u0026thinsp;=\u0026thinsp;0.61 (6 ms); S18\u0026thinsp;=\u0026thinsp;0.48 (8 ms); S16\u0026thinsp;=\u0026thinsp;0.51 (31 ms); S10\u0026thinsp;=\u0026thinsp;0.70 (1 ms). From this, the mean cross-correlation in 10 individual children was 0.89 with a standard deviation of 0.19. The mean lag was \u0026minus;\u0026thinsp;0.29 ms, with a standard deviation of 25.42 ms. Note: a positive lag means that the maximum cross-correlation was achieved when the CI eCAEP waveform is shifted later in time, and a negative lag means that the maximum cross correlation was achieved when the CI eCAEP is shifted earlier in time in comparison to the scalp eCAEP waveform.\u003c/p\u003e \u003cp\u003eGenerally, it can be observed that while component latencies are similar, amplitudes in the implant recordings are higher than those from surface electrodes. Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e details the means, ranges, and standard deviations of latencies and amplitudes for each response component, as well as the correlation coefficients between the two types of recordings. An ANOVA test for differences in latencies of various components of the cortical response showed no significant differences between CI recordings and scalp electrode recordings. In contrast to latencies, amplitudes of each component P1 (ANOVA p\u0026thinsp;\u0026lt;\u0026thinsp;0.03) N1 (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), P2-(p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) were significantly larger in CI recordings relative to scalp recordings. The average amplitude of the P1 component in CI recordings was 2.6 times larger than that of scalp recordings, N1 was 4.2 times larger, and P2 was 3.6 times larger. The mean cross correlations across subjects between the two types of eCAEP were 0.5 (with mean lag of 6.3 msec), ranging from 0.18 (with lag of 15 msec) to 0.89 (with lag of 2 msec).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eshows the means, ranges, and standard deviations of latencies and amplitudes for each response component, as well as the correlation coefficients between the two types of the recordings (CI and scalp).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLatency\u0026rsquo;s Component (ms)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eScalp or CI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMinimum\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eMaximum\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eLP1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eScalp\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e89.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e119\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e93.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e122\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eLN1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eScalp\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e138.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e177\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e138.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e22.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e179\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eLP2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eScalp\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e245.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e37.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e188\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e317\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e246.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e38.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e194\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e330\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003eAmplitude\u0026rsquo;s Components (\u0026micro;V)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAP1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eScalp\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e9.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e14.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAN1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eScalp\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e21.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAP2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eScalp\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e12.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePoint to Point Correlation Coefficients\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.89\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e\n\u003ch3\u003eClinical Relevance:\u003c/h3\u003e\n\u003cp\u003eTo demonstrate the possible association between auditory performance with CI and eCAEPs, Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e shows the grand average eCAEP of 13 pediatric participants with maximal 7th level of the CAP who were implanted at young age between 0.6 to 6.7 years and are currently 2.5 to 16.7 years old. Their average eCAEP response was compared to a group consisting of 7 children, implanted between 0.6 to 8.7 years after birth and currently ages between 4.1 to 16.6 years old. The eCAEP of the better performing group showed early P1 latency and higher eCAEP amplitudes as compared to the low performing CAP children. Figure\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e shows the box plot including the median and quartiles of P1 latency measured in the 13 participants with score of 7 in CAP compared to 7 children with CAP scores of 3,4 and 5 levels. ANOVA revealed that the latency of P1 was significantly shorter in the group with CAP 7 (89.3\u0026thinsp;\u0026plusmn;\u0026thinsp;16.2 ms) than the group with poorer CAP scores (122.8\u0026thinsp;\u0026plusmn;\u0026thinsp;23.6 ms). In average, N1 latencies were also shorter in the first (142.8\u0026thinsp;\u0026plusmn;\u0026thinsp;20.4 ms) than the second group with low scores of CAPs, however it did not reach to a significant level. Regarding amplitudes, P1 (4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9\u0026micro;V) and N1 (9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.6\u0026micro;V) were higher in the better CAP group, but reached to a significance different only in N1 (df (1,18)\u0026thinsp;=\u0026thinsp;4.6,p\u0026thinsp;=\u0026thinsp;0.04).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e illustrates the impact of cochlear implantation timing since the onset of deafness on eCAEP waveforms in two children with congenital hearing loss, currently aged 10 and 16 years, who were implanted at 10 and 15 months respectively (pre-lingual). Their eCAEP waveforms are compared to those of two adults with progressive hearing loss from birth, currently aged 29 and 48 years, who were implanted at 24 and 38 years (post-lingual).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAs observed, the pre-lingual children exhibit waveforms with shorter component latencies and larger amplitudes compared to the post-lingual adults. P1 latencies for the children were 75 and 91 ms, N1 were 149 and 154 ms, and P2 were 232 and 218 ms. In contrast, for the adults, P1 was recorded at latencies of 133 and 149 ms, N1 at 161 and 210 ms, and P2 at 228 and 262 ms. In pre-lingual children, component amplitudes ranged from 10 to 15 \u0026micro;V, while in adults, they were only 3 to 5 \u0026micro;V.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study aimed to investigate the feasibility and validation of electrical stimulation and recording of long-latency auditory evoked potentials (eCAEPs) directly from cochlear implant systems in a group of bilaterally implanted 20 children and 3 adults AB CI users. In this unique technique of recording, the implant systems effectively functioned as bidirectional wireless interfaces, enabling both stimulation and recording of the responses. To validate the compatibility of the cortical response pattern and its characteristics with standard EEG-derived responses, we conducted simultaneous direct recordings from the implant and scalp surface electrodes, processing the latter through a standard EP system. Additionally, to assess the reliability of the eCAEP, we examined response repeatability across two sets of consecutive stimuli within the same session and between sessions conducted months apart. We also demonstrated the effect of electrical stimulation intensity on the eCAEP to MCL, moderate softer and zero CU levels of electrical stimulation. Our findings demonstrate that eCAEP were successfully recorded from all pediatric and adults CI users with functional implants and with continuous use of the implant. No participants requested to discontinue the examination prematurely. The recording time for 150 stimuli was approximately 4 minutes, which is considered reasonable for clinical examination, even for young children. This suggests that the eCAEP recording procedure is well-tolerated and potentially suitable for routine clinical use.\u003c/p\u003e \u003cp\u003eThe eCAEP exhibited high test-retest reliability, demonstrating consistent waveform morphology and component characteristics both within individual sessions and across follow-up sessions conducted months apart. To quantify this reliability, we calculated the correlation coefficients for the latencies and amplitudes of the P1, N1, and P2 eCAEP components. The coefficients for latencies ranged from 0.7 (P2) to 0.94 (P1) and for amplitudes 0.84 (P2) to 0.89 (N1), indicating a strong to high level of reliability. Additionally, we performed repeated-measures ANOVA on these components, comparing data from the initial examination with those from follow-up sessions. Results revealed no statistically significant differences in any of the components. A similar high test-retest repeatability of eCAEPs recorded by AB CI system in adults was previously reported \u003csup\u003e\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e\u003c/sup\u003e. These findings provide strong evidence for the stability and reliability of eCAEP measured directly by the CI system over time, supporting their potential use in longitudinal clinical assessments of auditory cortical function in children and adults cochlear implant users. These findings also are in line with similar high test-retest reliability often seen in the CAEP recorded by scalp electrode in children and adults using CI or normal children \u003csup\u003e\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e,\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e,\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e\u003c/sup\u003e.\u0026rlm;\u003c/p\u003e \u003cp\u003eBell-Souder et al.\u003csup\u003e\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e\u003c/sup\u003e demonstrated the feasibility of recording eCAEP using an intra-cochlear montage in 7 adult cochlear implant users. The study included participants aged 19 to 82 years, with six individuals implanted between 42 and 78 years of age, and one participant implanted at 9 years old. However, unlike the current study where P1 was identified in all participants, their research encountered difficulties in identifying P1 in 4 out of 7 subjects. This difference likely stems from the nature of stimuli used in both studies. In the current pediatric study, the stimulus was a 10 ms electrical pulse delivered to a single apical electrode (number 1). In contrast, the previous work used a 20 ms speech stimulus (/uh/) presented to the first 8 apical electrodes. This stimulus presumably elicited a larger artifact in the stimulating implant, which spread and was recorded in the contralateral recording implant, making it challenging to identify the response shortly after stimulus onset in some implanted subjects. In the current study, due to the nature of the stimulus, the artifact was smaller and ended before the onset of the P1 component. Nevertheless, mean P1-N1 wave latencies in adults were 36.6\u0026thinsp;\u0026plusmn;\u0026thinsp;7.4 and 86.2\u0026thinsp;\u0026plusmn;\u0026thinsp;9.7 ms, respectively. In addition, age is a factor, children have longer P1 latencies than adults, which makes it easier to identify beyond initial artifacts. The current study found mean P1-N1 latencies in children to be 100\u0026thinsp;\u0026plusmn;\u0026thinsp;23.1 and 146\u0026thinsp;\u0026plusmn;\u0026thinsp;21 ms, respectively. Differences in wave latencies between children and adults are expected given the variations in participant age and cortical maturation \u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e,\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e\u003c/sup\u003e. The P1 latency data from this study shows that 17 out of 20 children fall within the normal range for their age (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). One child (S11), aged 5.9 years, exhibited earlier P1 latency than expected for their age. This child received bilateral simultaneous cochlear implants (CIs) at 8 months old and is a very good performer with CIs (CAP score 7; 100% speech intelligibility in quiet and 90% in noise). In contrast, two children (S8 and S9) showed late eCAEPs. They are currently 13.4 and 11.1 years old and were implanted at 0.9 and 8.7 years, respectively. Both are from the same signing family, attend educational frameworks for the deaf, and are considered poor performers with CIs (CAP scores 3 and 5; speech intelligibility less than 50% in quiet and less than 30% in noise). Further distinctions between early and late cochlear implantations has been shown between adult post lingual and children pre-lingual CI users. These cases illustrate the ability of the test to reflect, through the and prepattern but primarily through the P1-N1 latency components, the performance of implant recipients. This performance is influenced both by the timing of the implantation and by the necessity for continuous auditory input to achieve maximal neural plasticity in response to electrical stimuli. Our demonstrations with the intra-cochlear eCAEP are align with previously reported findings from scalp-recorded CAEPs in these groups \u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e,\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e,\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e,\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e\u003c/sup\u003e. These further reinforce the validity of using eCAEPs as a tool for evaluating auditory performance and highlight the necessity of further investigation and expansion of clinical applications utilizing eCAEPs.\u003c/p\u003e \u003cp\u003eA requested aspect in validating and optimizing the use of cochlear implant (CI) systems for recording intracochlear brain potentials is comparing them to conventional scalp-recorded brain potentials. The current study has demonstrated the similarity between these two recording methods, particularly in terms of peaks latencies. The correlation coefficients between the individual scalp and the CI recorded eCAEP ranged between 0.18 to 0.89 with a mean of 0.5. ANOVA found no significant differences in the latencies of P1, N1, and P2 peaks between intracochlear CI recordings and scalp recordings. However, a notable distinction lies in the peak\u0026rsquo;s amplitudes. The eCAEP recorded by CI demonstrates significantly higher amplitudes compared to scalp-recorded potentials, with P1, N1, and P2 components showing 2.5, -3.6-, and 4.3-times greater amplitudes, respectively. These enhanced amplitudes can be attributed to both the properties of the recording electrodes, the differences in tissue conductivity and in the proximity to the eCAEP generators located in the brain. The montage of the CI recording array includes an active intracochlear electrode referenced to an electrode embedded subcutaneously in the temporal bone. This array is situated in a conductive medium with superior conductivity compared to the scalp recording array. The distance between the scalp and brain varies significantly with the age of the brain region. In newborns, the mean brain-scalp distance across the entire brain surface is approximately 5.9\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 mm, increasing to about 10.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9 mm by age 7 \u003csup\u003e55\u003c/sup\u003e and to 23.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7 mm un adults. The proximity of the CI electrodes to the auditory cortex in children, where CAEP generators are primarily located, allows for more direct recording of neural activity, improved signal-to-noise ratio, reduced interference from external noise and biological artifacts, leading to enhanced eCAEP amplitudes recorded compared to the scalp recorded. The larger eCAEP amplitudes recorded through CIs in children can significantly improve clinical applications of cortical potential, facilitating more precise assessment and monitoring of auditory function in pediatric CI recipients. These enhanced signals should offer more robust and sensitive measures of cortical responses, potentially enabling more accurate tracking of auditory development, neural plasticity, and rehabilitation progress. The increased amplitude could allow for more refined device programming and individualized intervention strategies, ultimately supporting more effective auditory rehabilitation in children with cochlear implants. However, since this is the first time such enhanced amplitudes have been observed in this context, further studies are needed to confirm these findings and fully elucidate their clinical implications. Additional research will be crucial to validate the reliability and clinical utility of these enhanced eCAEPs in pediatric CI users across different age groups and listening conditions.\u003c/p\u003e \u003cp\u003eThe significant enhancement of eCAEP amplitudes observed in this study is in line with the report on a similar trend of enhancement shown in 7 adult AB CI users \u003csup\u003e\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e\u003c/sup\u003e and in 2 adults subjects using eCAEP recordings through a percutaneous connector with an electrode array of Cz and intra cochlear basal electrode \u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u003c/sup\u003e. Additionally, the current study supports bigger amplitudes of the eCAEP recorded by an epidural electrode in 10 adult CI users \u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eRecording eCAEPs directly from the CI at MCL and lower stimulation levels offers the potential for objective assessments of cochlear implant users, particularly in children who are unable to provide reliable behavioral feedback. To date, such assessments have been performed using scalp surface electrodes, demonstrating efficacy in estimating hearing thresholds \u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e,\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e,\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e\u003c/sup\u003e, objectively identifying MCL levels \u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e\u003c/sup\u003e, aiding implant mapping \u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e,\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e,\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e,\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e,\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e,\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e\u003c/sup\u003e, and evaluating and improving auditory performance in pediatric implant users \u003csup\u003e\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e\u003c/sup\u003e. By enabling the recording of eCAEPs directly from the implant without requiring additional external equipment, these clinical applications can now be conducted more conveniently and efficiently in children within a clinical setting. However, before broad clinical implementation, and given the variability observed in the effects of stimulus intensity on eCAEPs in the 11 children in this study, further investigation is needed. Expanding the study to include a larger cohort of children and employing a standardized testing protocol across participants is essential to better understand and account for the influence of stimulus intensity on eCAEP characteristics.\u003c/p\u003e \u003cp\u003eIn conclusion, this study, conducted with a group of 20 children and 3 adult CI users, demonstrated the feasibility and potential clinical value of directly recording eCAEPs in response to electrical stimuli from the CI system. The findings showed good test-retest repeatability, high similarity to scalp-recorded CAEPs, and promising preliminary insights into the effects of electrical stimulus levels on eCAEP characteristics. The short test duration of less than 5 minutes further supports its practicality for clinical use. These results highlight the potential of eCAEP recordings as a valuable tool for assessing and monitoring auditory performance in children with CIs. Additionally, this study builds on previous findings that demonstrated the feasibility of recording CAEPs in response to acoustic stimuli in children and adults with residual hearing and to electrical stimuli in adults CI users \u003csup\u003e\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e\u003c/sup\u003e. Overall, these CI CAEP studies represent a significant advancement in expanding the range of available closed-loop objective measures in CI, beyond peripheral responses (e.g. Neural Response Imaging (NRI) and Electrically Evoked Cochleography (eCochG). By introducing a novel brain-based objective measure, they provide a new tool for evaluating and optimizing auditory performance without requiring active participation from patients, which is particularly beneficial for children.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eParticipants and ethics declarations\u003c/h2\u003e \u003cp\u003eIn this study 20 children aged from 2.5 to 17 years and 3 adults 21, 28 and 48 years (13 females and 10 males) participated. All were bilateral AB CI users. All children had congenital severe to profound hearing loss and were implanted in both ears at young ages ranging from 7 months to 4 years from birth. The three adults were post-lingual implanted sequentially between 8 years to 25 years post hearing loss onset. Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e details the demographic data of each subject including, age of implantation, implant type and electrode type, etiology of deafness, and the Category of Auditory Performance (CAP) score. CAP is a standardized scale for assessing auditory outcomes in children with cochlear implants. The scale consists of eight performance categories arranged in ascending order of difficulty, from no awareness of environmental sounds (0 score) to the ability to use a telephone with a familiar speaker (7 score). The CAP scale evaluates children's daily auditory and verbal skills, reflecting their hearing improvement during follow-up sessions after cochlear implantation. The table also details the participants who, in addition to recordings of eCAEP to comfortable levels, took part in examining the influence of additional factors on the potential. These participants were selected due to their willingness, relatively older age, and tolerance for a longer research session. Subjects or their parents provided written informed consent to participate in the study, but they were free to stop their participation at any point during the study. The protocol of the study was approved by the Investigational Review Board (IRB:. 0617-19-RMC, Schneider Children Medical Center, Israel) and all methods were performed in accordance with the relevant guidelines and regulations. The current mean age of the CI children group was 11.09\u0026thinsp;\u0026plusmn;\u0026thinsp;4.1 yrs with a minimum of 2.5 yrs and maximum of 16.7 yrs. The mean implantation age was 2.3\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3 yrs ranging from 0.6 to 8.7 post-natal years. All had congenital deafness with etiologies including genetic (11) Auditory Neuropathy (2), LVA (1), CMV (1) and the rest with unknown source (5). The current age of the three adults is 21,29 and 48 years, all had congenital deafness from unknown etiology and received CI at 2.4, 46 and 3 years respectively. In the children\u0026rsquo;s group CAP scores range between 7 (13 children) and 5(4). 4 (2) and 3 (1). The 3-adult scored 7 (1 adult) and 4 (2).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAge at the test, gender, age at CI, etiology of deafness, CI and electrode type, Category of Auditory Performance. In the last column, description of the subjects who participated in evaluations of: \u003cb\u003e*\u003c/b\u003eeCAEP Repeatability; +Effect of stimulus level on eCAEP; \u003csup\u003e\u003cb\u003eX\u003c/b\u003e\u003c/sup\u003e Comparison of eCAEP Scalp vs CI recordings.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"9\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSubject #\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAge Now (yrs)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGender\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eImplantation\u0026rsquo;s Age (yrs)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eEtiology\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eImplant Type Right\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eCI\u003c/p\u003e \u003cp\u003eElectrode\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eCAP\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eSubjects used for the effects on eCAEP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGenetic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eMS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e*X\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGenetic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires Ultra 3D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eSlimJ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAuditory Neuropathy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires Ultra 3D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eSlimJ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGenetic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1J\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eUnknown\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires Ultra 3D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eSlimJ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e* X\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGenetic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K Advantage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1J\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e* +X\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGenetic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K Advantage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eMS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e+\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eUnknown\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1J\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eUnknown\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K Advantage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eMS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAuditory Neuropathy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires Ultra 3D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eSlimJ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eUnknown\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires Ultra 3D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eSlimJ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCMV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K Advantage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eMS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e* X\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eUnknown\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires Ultra 3D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eSlimJ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e* X\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGenetic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eIJ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e*+X\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGenetic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1J\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e*+X\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGenetic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K Advantage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1J\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e+X\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLVA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K Advantage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eMS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGenetic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K Advantage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eMS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e*+ X\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGenetic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K Advantage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1J\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eGenetic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires Ultra 3D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eSlimJ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eUnknown\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires Ultra 3D\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eMS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e48.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eUnknown\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires Ultra\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eSlimJ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e28.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eUnknown\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eHires 90K\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eIJ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eTest Set-Up and Recording Parameters\u003c/h3\u003e\n\u003cp\u003e \u003c/p\u003e \u003cp\u003eIn the current study, bilateral CIs were used such that one CI served as the electrical stimulator while the contralateral CI functioned as an EEG recording system. The Advanced Bionics (AB) system comprised the following components: the AB Clinical Programming Interface (CPI-3), which was connected to a PC on one end and to the second Na\u0026iacute;da CI Q90 speech processor on the other end. Each of the two speech processors was connected to an RF cable and headpiece for communication with the internal implant in each ear of the bilaterally implanted participants.\u003c/p\u003e \u003cp\u003eThe speech processors were also connected to a trigger dongle, which facilitated the delivery or reception of trigger signals. Only one speech processor functioned as the stimulating processor, delivering electrical stimuli to the corresponding ear. This stimulating processor, referred to as the ipsilateral processor, generated a trigger signal at the onset frame of the electrical stimulus, which was sent to the second processor, referred to as the contralateral processor. Simultaneously, the ipsilateral processor provided the same trigger signal to the \"trigger in\" port of a Biologic standard evoked potential (EP) system (Navigator-Pro Evoked Potential System, Bio-Logic Systems Corp., Mundelein, IL, USA). This later configuration allowed for the examination of the correlation between cortical auditory evoked potentials (eCAEP) recorded via the scalp (using the EP system) and those recorded via the contralateral CI. All eCAEP presented in this study were collected from the contralateral (non-stimulating) side.\u003c/p\u003e \u003cp\u003eThe electrical stimulus evoking eCAEP was a biphasic pulse train of 10 msec duration. Stimulus phase polarity is cathodic (negative phase first). The duration of each phase was set to 36 microsec. These parameters of the electrical stimulation were fixed and not change across all participants, unless the impedance values at the stimulating electrode is too high, which causes the stimulus to be out of compliance, then the phase duration was increased to higher value than 36 \u0026micro;s. The number of sweeps across all participants was 150 sweeps which took around 4 minutes for each experiment trial. Presentation level of the electrical stimulation was set based on the user feedback reported when reaching sound level of loud and comfortable. For Subjects that can\u0026rsquo;t provide any feedback, Presentation level was set based on daily map M levels at the stimulating electrode. The duration of each sweep will be explained in detail in a later section.\u003c/p\u003e \u003cp\u003eFor the purpose of this study, we used Advanced Bionics\u0026rsquo; proprietary research software BEEP (Bionics Ear Evoked Potential, BEEP version 1.1.0.1) app for direct CI eCAEP recording. The BEEP app controlled the experimental CI setup and manipulation of all parameters mentioned previously and allowed synchronization and trigger communication between both processors, and between AB CI system and the standard EP recording system.\u003c/p\u003e \u003cp\u003eFollowing the presentation of the electrical signal to the stimulated CI system, the standard EP system began the CAEP recording via the scalp electrodes, while the CI recorded eCAEP directly through intracochlear electrodes from the non-stimulating side. The BEEP App controlled the CPI-3, two Naida CI Q processors, and the implant through Advanced Bionics implant system. This software removed the necessity to concatenate smaller recording snippets to capture the whole eCAEP response, as done by previous studies e.g. \u003csup\u003e\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e\u003c/sup\u003e. This enabled recording for longer durations than the standard CI-related objective measures such as eCAP and ECochG. The electrical stimulus to the ipsilateral CI system was presented to the apical electrode number 1 while the eCAEP recording was done via the basal electrode 13. The recording electrode was chosen based on the low impedance level and sometimes based on the presence or absence of NRI responses at this electrode. If it was not possible to record from electrode 13 due to a technical reason, mainly high impedance value, then electrode 12 or 14 was chosen. The stimulating electrode reference was the ground electrode located in the CI housing, i.e. the case ground, and the recording electrode reference was the ground case electrode located at the lead of the electrode array as detailed in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e, the recorded EEG via the implanted electrodes was collected back, by RF backward telemetry to the processor and then to BEEP App for visualization and signal processing. Simultaneously, the CAEP recorded by the scalp montage (Fz-Mastoid) and collected for signal processing by the external EP system. In this study, the single-channel CI eCAEP was compared with the most common single-channel scalp recording (Fz-Mastoid) as described by (Lightfoot \u0026amp; Kennedy 2006). The gain of the internal differential amplifier of the AB implants was fixed and set to 1000, and its output was sampled at a frequency of 1000 Hz. The low pass cut-off frequency was set at 5 kHz.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eData collection technique:\u003c/h3\u003e\n\u003cp\u003eAs detailed in Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e, each CI eCAEP measurement \u0026ldquo;sweep\u0026rdquo; consisted of two parts. The first one is the \u0026ldquo;null\u0026rdquo; part, which presents a zero-amplitude stimulation followed by a recording window with a duration of 500 msec. The duration of the recording window is set within the BEEP app. The second part is the \u0026ldquo;stim\u0026rdquo; part, which presents an MCL amplitude stimulation followed by a recording window with a duration of 500 msec (same length as the \u0026ldquo;stim\u0026rdquo;). Each CI eCAEP run consisted of 150 sweeps. For testing repeatability of the e-ACEP, two consecutive trials at the MCL level were conducted.\u003c/p\u003e \u003cp\u003eThe standard EP system recorded the eCAEP via scalp electrodes receiving trigger concurrent to the presentation of the electrical stimulus at the ipsilateral side, and the start of e-CAEP recordings via the contra lateral CI system. For the standard EP system, the active electrode was attached to the forehead, the reference electrode to the mastoid or the lobule with the contra lateral CI, and the ground electrode to the mastoid or lobule of the stimulated CI side. A filter device was placed between the patient and the EP system to eliminate any RF artifacts using a 34 kHz low pass filter. The EEG activity was bandpass filtered from 1 (12 dB/octave) to 100 Hz. A notch filter was also used to remove the power line frequency noise. The EEG activity was then amplified by 50,000 and sampled in a window of 533 ms (512 data points per sweep at a sampling rate of 1,000 Hz).\u003c/p\u003e \u003cp\u003eTesting was performed in a standard sound booth and participants were seated in a recliner chair. Participants and/or guardians were given a full explanation of the procedure before starting measurements. The external scalp electrode impedance was kept less than 3 KΩ to decrease any external noise because of high impedances. CI impedance levels for the implanted electrode array were all measured to be within normal limits (between 1 and 30 kΩ as per clinical guidelines). The ideal value of the impedance for the recording electrode was chosen to be less than 10 KΩ if feasible.\u003c/p\u003e \u003cp\u003eAdult participants and the teenager participant were asked to count the electrical stimuli during testing while the children under 6 years old were offered a tablet with a muted video during testing, to keep the participants awake and alert to minimize eye-blink artifacts, and to minimize hand or finger movements. Participants were able to take a short break between recording sessions.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eData Analysis\u003c/h2\u003e \u003cp\u003eThe collected CI CAEP data was post processed in an additional Matlab app that was developed for this purpose. As mentioned before, each recorded data set contained 150 measurement sweeps. All data points of the standard scalp electrode CAEP were inverted in polarity (negative sign) before further processing to match the recording montage of the CI eCAEP (intracochlear electrode #13 referred to the case). For each measurement trial, the \u0026ldquo;null\u0026rdquo; sweeps were subtracted from the \u0026ldquo;stim\u0026rdquo; sweeps. The sweeps then were averaged, linear data trend was removed, then filtered by a second-order infinite impulse response filter (IIR filter) with a bandpass of 1 Hz and 20 Hz followed by the application of a moving average technique with a time window of 33 msec.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThere were two main limitations faced during the research when recording cortical responses from the CI system. The first one is the recording artifact or recording noise, which presents the electrical circuit behavior, and it is present whenever the implant initializes a recording window and starts recording the cortical response. This noise is present in both, the ipsilateral side and the contralateral side implants, and also during zero stimulation (\u0026ldquo;null\u0026rdquo; stage) and high amplitude stimulation (\u0026ldquo;stim\u0026rdquo; stage). To resolve the recording artifact, subtracting the \u0026ldquo;null\u0026rdquo; from \u0026ldquo;stim\u0026rdquo; technique was used. During the recording of the \u0026ldquo;null\u0026rdquo; stage, which is preceded by the 10 msec duration of zero amplitude stimulus, the recording object will apparently record no cortical response and no stimulus artifact as there was no stimulus present prior to it. The only data that will be recorded is the circuit behavior, which is assumably the same for that specific recording trial. For the \u0026ldquo;stim\u0026rdquo; stage, which is preceded by the 10 msec duration of MCL amplitude stimulus, the recording object will record the cortical response, the stimulus artifact and the noise of the circuit behavior. The noise of the circuit behavior is considered to be the same as for the \u0026ldquo;stim\u0026rdquo; stage and can be subtracted from it and eliminated.\u003c/p\u003e \u003cp\u003eThe second limitation is the electrical stimulus artifact. The greater the amplitude of the stimulus, the greater the artifact. In order to avoid the stimulation artifact, the cortical responses were reported only from the contralateral side (the non-stimulating side), and the recording from the ipsilateral side was ignored. Combining the two solutions will lead to the conclusion to record the responses from the contralateral side using the subtraction of the \u0026ldquo;null\u0026rdquo; stage from the \u0026ldquo;stim\u0026rdquo; method. In the process of collecting the data from the ipsilateral side, i.e. stimulating and recording on the same side, the presence of stimulation will cause the presence of its artifact, which can be significant at high stimulation amplitudes. On the other hand, the process of collecting the data from the contralateral side, i.e. stimulation on one ear and recording the response from the other ear, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e13\u003c/span\u003e, the stimulation artifact is not present in the contralateral ear. Therefore:\u003c/p\u003e\u003cp\u003e\u003cimg 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\" width=\"585\" height=\"152\"\u003e\u003c/p\u003e \u003cp\u003eFollowing offline analysis, author JA, blinded to the recording method (cochlear implant or scalp recording), manually identified the peak latencies of the P1, N1, P2, and N2 components. The identification process was guided by previous reports on scalp-recorded eCAEP in normal-hearing individuals and pediatric cochlear implant users \u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. For the eCAEP in children, P1 was defined as the most prominent positive peak occurring between 55 ms and the subsequent largest negative peak (N1) within 200 ms after stimulus onset. P2 was identified as the largest positive peak following N1, occurring up to approximately 280 ms, while N2 was marked as the subsequent negative peak following P2, occurring within 370 ms post-stimulus. In addition, peak-to-peak amplitudes were calculated for P1 (P1-N1), N1 (N1-P2), and P2 (P2-N2) components.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eStatistical analyses were conducted using SPSS software (version 25; SPSS Inc., Chicago, IL, USA). Descriptive statistics were utilized to summarize data, including mean, minimum, maximum, and standard deviation values for the latencies and amplitudes of the P1, N1, and P2 eCAEP components. These metrics were also detailed for the most comfortable listening (MCL) levels, responses at softer amplitudes, repeated measurements, and comparisons between scalp-recorded and cochlear implant (CI)-recorded eCAEP.\u003c/p\u003e \u003cp\u003eRepeated measures ANOVA was employed to evaluate test-retest reliability, as well as the effects of stimulation level and recording method on eCAEP metrics. Pearson correlation analysis was performed to assess the relationship between eCAEPs recorded via scalp and CI methods. Statistical significance was defined as a p-value of less than 0.05.\u003c/p\u003e \u003cp\u003eDeidentified versions of the datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e \u003c/div\u003e "},{"header":"Declarations","content":" \u003cp\u003e \u003cstrong\u003eCompeting interests\u003c/strong\u003e \u003cp\u003eAuthor Suhail HabibAllah is a current employee of Advanced Bionics, Israel. Author Chen Chen is a current employee of Advanced Bionics, USA. Author Joseph Attias declares no potential conflict of interest.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eConcept: S. H., J. A., C. C; Design: S.H, C.C; Data acquisition: S.H, J.A.; Analysis and interpretation: S.H, J.A., C.C; writing: J.A., S.H., C.C.; Suhail HabibAllah and Joseph Attias are considered as equal contributors in writing the article.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors extend their gratitude to Kanth Koka, PhD, for his valuable and insightful feedback on the research setup and an earlier draft of this article. They also wish to express their heartfelt thanks to the study's participants and their parents for their cooperation and support.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe data supporting this study will be made available upon reasonable request in an anonymized format. The request should be addressed to [email protected] .\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSharma, A., Nash, A. A., \u0026amp; Dorman, M. Cortical development, plasticity and re-organization in children with cochlear implants. Journal of Communication Disorders, 42(4), 272-279 (2009).\u003c/li\u003e\n\u003cli\u003eKral, A., Dorman, M. F., \u0026amp; Wilson, B. S. Neuronal development of hearing and language: Cochlear implants and critical periods. Annual Review of Neuroscience, 42(1), 47-65 (2019).\u003c/li\u003e\n\u003cli\u003eQiao, X. F., Liu, L. D., Han, L. Y., Chen, Y., \u0026amp; Li, X. Exploring cross-modal plasticity in the auditory\u0026ndash;visual cortex post cochlear implantation: Implications for auditory and speech function recovery and mechanisms. Frontiers in Neuroscience, 18, 1411058 (2024).\u003c/li\u003e\n\u003cli\u003eKartheiser, G., Cormier, K., Bell-Souder, D., Dye, M., \u0026amp; Sharma, A. Neurocognitive outcomes in young adults with cochlear implants: The role of early language access and crossmodal plasticity. 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L., Friesen, L., Martin, B. A., \u0026amp; Wright, R. Test-retest reliability of cortical evoked potentials using naturally produced speech sounds. Ear and Hearing, 24(3), 225-232 (2003).\u003c/li\u003e\n\u003cli\u003eT\u0026aacute;vora-Vieira, D., Wedekind, A., Ffoulkes, E., Voola, M., \u0026amp; Marino, R. Cortical auditory evoked potential in cochlear implant users: An objective method to improve speech perception. PLOS ONE, 17(10), e0274643 (2022).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Cortical Auditory Evoked Potentials, Intra-Cochlear Recordings, Pediatric, Scalp Recordings, electrical stimulation, Brain Objective measure","lastPublishedDoi":"10.21203/rs.3.rs-6170473/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6170473/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Intracochlear electrodes in cochlear implants (CIs) offer a novel method for recording auditory brain activity without external EEG equipment, addressing challenges in pediatric CI users. This study tested the feasibility of recording electrically evoked cortical auditory evoked potential (eCAEPs) directly via the CI system. Twenty children and three adults with bilateral Advanced Bionics CIs participated. A brief electrical stimulus was delivered to one CI, while the contralateral CI recorded responses using a basal electrode referenced to the case. Each session included stimulus and non-stimulus sweeps, with averaging over 600 ms revealing clear eCAEP patterns. All participants exhibited obligatory P1, N1, and P2 peaks within a test duration of under five minutes. The method showed good test-retest repeatability and expected latency shifts occurred with stimulus level adjustments. Compared to scalp recorded EEG, intracochlear recordings produced significantly larger amplitudes with similar latencies. Early-implanted children displayed distinct eCAEP patterns, and better performing CI users had earlier P1 responses. This recording approach provides a robust, non-invasive tool for monitoring CI users, particularly young children, offering potential advancements in post-implantation assessment and intervention by eliminating external equipment while ensuring reliable recordings.","manuscriptTitle":"Electrically evoked cortical potentials recorded directly from cochlear implant system: Feasibility in pediatric users and clinical relevance","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-03-27 09:20:37","doi":"10.21203/rs.3.rs-6170473/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-04-09T08:27:20+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-07T13:58:12+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-01T09:00:30+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"105229791514815557751280638224216996543","date":"2025-03-24T08:27:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"128942538958136802315793593450706404563","date":"2025-03-21T22:30:27+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-03-18T15:48:00+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-03-18T15:46:45+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-03-17T17:08:10+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-03-17T05:01:46+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-03-06T12:10:57+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"946bdf8d-8c00-411c-b1c6-2ff44e59db3d","owner":[],"postedDate":"March 27th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":46108086,"name":"Biological sciences/Neuroscience/Auditory system"},{"id":46108087,"name":"Biological sciences/Neuroscience/Auditory system/Cochlea"},{"id":46108088,"name":"Biological sciences/Neuroscience/Auditory system/Cortex"}],"tags":[],"updatedAt":"2025-07-07T16:14:57+00:00","versionOfRecord":{"articleIdentity":"rs-6170473","link":"https://doi.org/10.1038/s41598-025-06652-z","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-07-02 15:57:50","publishedOnDateReadable":"July 2nd, 2025"},"versionCreatedAt":"2025-03-27 09:20:37","video":"","vorDoi":"10.1038/s41598-025-06652-z","vorDoiUrl":"https://doi.org/10.1038/s41598-025-06652-z","workflowStages":[]},"version":"v1","identity":"rs-6170473","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6170473","identity":"rs-6170473","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}