Transcutaneous Auricular Vagus Nerve Stimulation Enhanced Working Memory in Older Adults with Age-Related Hearing Loss

Transcutaneous Auricular Vagus Nerve Stimulation Enhanced Working Memory in Older Adults with Age-Related Hearing Loss | 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 Transcutaneous Auricular Vagus Nerve Stimulation Enhanced Working Memory in Older Adults with Age-Related Hearing Loss Junyoung Shin, Shinhee Noh, Jimin Park, Sang Beom Jun, Jee Eun Sung This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5002507/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 Jul, 2025 Read the published version in Scientific Reports → Version 1 posted 12 You are reading this latest preprint version Abstract Age-related hearing loss (ARHL) is associated with an increased risk of dementia, necessitating early cognitive interventions to prevent further cognitive decline. Despite promising evidence supporting transcutaneous auricular vagus nerve stimulation (taVNS) for mitigating cognitive impairment, its impact on working memory (WM) in older adults with ARHL is unexplored. This study is the first attempt to investigate taVNS effects on WM in the older adults with hearing impairment (HI) and with typical hearing (TH). WM capacity was assessed using n-back tasks, varying by WM domains (verbal and visuo-spatial) and complexity levels (1-back and 2-back). Participants underwent a two-session, within-subjects, randomized crossover, single-blind sham-controlled protocol, receiving 20 minutes of continuous stimulation in the active session, whereas only 30 seconds at the start and end in the sham session. The HI group performed significantly worse than the TH group on the 2-back tasks. Within the HI group, taVNS significantly enhanced performance across all WM domains and complexity levels compared to the sham condition. These findings suggest that taVNS enhances WM in hearing-impaired older adults, underscoring its potential as a clinical intervention for addressing WM challenges associated with ARHL. Age-related hearing loss Cognitive intervention Transcutaneous auricular vagus nerve stimulation Working memory N-back task Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction During the advanced stages of human aging, individuals typically encounter a range of physical and cognitive deteriorations. These changes include modifications in the structural and functional aspects of the auditory system. Consistent evidence from epidemiological studies strongly links sensory loss related to hearing with an elevated risk of developing dementia 1 , 2 , with this link becoming more pronounced with age 3 . The deprivation hypothesis, proposed by Baltes and Lindenberger 3 , has gained substantial support in explaining these connections 4 – 7 . It posits that prolonged periods of reduced auditory input over time due to untreated hearing impairment (HI) can lead to alterations in neural networks, subsequently affecting cognition and processing speed 8 . Overall, older adults with HI are now identified as preventative clinical populations in need of early cognitive interventions, given their demonstrated cognitive deficits relative to those with normal hearing 9 , 10 . Noninvasive brain stimulation, particularly transcutaneous auricular vagus nerve stimulation (taVNS), has garnered recognition for modulating cognition by targeting the auricular branch of the vagus nerve. Research has covered various cognitive domains through taVNS, such as executive functions 11 , and inhibitory controls 12 , with notable improvements on memory functions 13 – 18 . A recent study highlighted its potential to improve working memory (WM), particularly in the visuo-spatial n-back task performance, within a cohort of healthy young adults aged 18 to 23 years 19 . Further, patients with mild cognitive impairment (MCI) exhibited notable improvements in verbal memory functions, including both immediate and delayed recalls, following a 24-week intervention of taVNS 18 . These studies highlight taVNS as a promising noninvasive approach for improving memory issues and potentially mitigating cognitive decline associated with aging. Recent studies are increasingly focusing on the link between cognitive decline and age-related hearing loss (ARHL), especially utilizing WM tasks to explore this relationship 20 – 22 . Previously, a marked correlation was observed between hearing ability, as indexed by peripheral auditory thresholds, and WM functioning in a group of 156 individuals aged 70 and above 3 . This study highlighted early markers and intervention points for cognitive decline with a specific emphasis on hearing loss in older adults as a possible precursor to dementia. More recently, an EEG study identified this connection by examining the association between hearing loss and WM functions, finding significant correlations between auditory P300 latency and WM capacity in individuals with HI 23 . Subsequent studies have further supported the idea that impaired hearing can significantly contribute to the deterioration of WM capacity 24 – 26 , suggesting that addressing ARHL early on could be a key intervention point for preventing cognitive decline. Extensive research on WM indicates that the specific domains and components of WM being targeted are considered critical when selecting WM tasks to examine individual differences in WM capacity 27 – 29 . For instance, in WM capacity across verbal and visuo-spatial domains, a study utilizing the digit and corsi span forward tests among patients in the early stages of Alzheimer's disease (AD) and healthy control subjects found a significant decline in the visuo-spatial WM domain among mild AD patients 30 . However, the differences between these patients and the control group in the digit span test were minimal. These findings highlight the significance of considering distinct WM domains of incoming information when evaluating WM capacity, particularly evident in cognitively impaired older adults 31 – 33 . Evidence from older adults with ARHL suggests that performance differences emerge depending on the WM task types, such as those in the verbal and visuo-spatial domains 20 – 22 . Some studies employed verbal WM tasks 21 , 22 , while others focused on the visuo-spatial domains of WM when studying older adults with ARHL 20 . The study, which examined the association between hearing ability and cognitive functions among older individuals with and without ARHL, focused on the verbal WM domain using the n-back task with letter presentation. It found that individuals with HI exhibited significantly slower reaction times and fewer correct responses on the 2-back task, although no substantial group differences were observed on the 0-back task 34 . Another group of researchers reported that individuals with HI exhibit WM deficits in the visuo-spatial domain, even in the absence of specific auditory challenges 20 – 22 , 35 . Despite the increasing research on WM deficits for older adults with ARHL, there have been no effort yet to apply the taVNS to improve WM functions for populations at risk of dementia due to ARHL. The current study aims to investigate the effects of taVNS on WM performance by systematically manipulating task complexity (1-back vs. 2-back) and WM domain (verbal vs. visuo-spatial). To the best of our knowledge, this represents the first attempt to examine these effects specifically in older adults with ARHL, a group in need of early cognitive intervention. Methods Participants The study involved 56 participants aged over 60 years, consisting of 20 individuals with HI and 36 typical hearing (TH). All participants, who were native Korean speakers, met the following criteria: they obtained scores within normal ranges on the Korean version of the mini mental state examination (K-MMSE) 36 , the Seoul verbal learning test (SVLT), the digit span tests from the standardized Seoul neuropsychological screening battery-II 37 , and a short version of the geriatric depression scale (< 8 out of 15) 38 . None of the participants reported any visual impairments, learning difficulties, or a history of brain injuries. All experiments were conducted in accordance with relevant guidelines and regulations. This research was approved by the Institutional Review Board on Human Subjects of Ewha Womans University (Approval No. 2022-0084), and all procedures were performed following ethical standards and institutional policies. Prior to participation, all individuals provided written informed consent. An independent sample t-test was conducted, revealing no statistically significant differences in age, education years, or screening results of neuropsychological tests between the TH and HI groups (all p-values > 0.05). Detailed demographic information and descriptive statistics are provided in Table 1 . Table 1 Participants’ descriptive information and screening results of neuropsychological tests; TH, Typical hearing; HI, Hearing impairment; M(SD), mean(standard deviation); K-MMSE, Korean version of the mini-mental state examination; SVLT-imme., Seoul verbal learning test - immediate recall; SVLT-delayed, Seoul verbal learning test - delayed recall; Digit span-F, Digit span test forward; Digit span-B, Digit span test backward; dB HL, decibels hearing level. TH Group n = 36 HI Group n = 20 Test statistics p-value Gender Male 23 (63.8%) 14 (70%) Female 13 (36.1%) 6 (30%) Age (years) M(SD) 64.03 (3.72) 65.55 (3.66) 1.481 0.146 Range 60–72 60–72 Education (years) M(SD) 14.56 (2.97) 13.95 (3.18) -0.698 0.490 Range 9–23 9–23 K-MMSE (max: 30) M(SD) 28.97 (1.36) 28.75 (0.96) -0.709 0.482 Range 26–30 26–30 SVLT-imme. (max: 36) M(SD) 21.28 (3.74) 20.45 (3.84) -0.780 0.440 Range 15–31 15–30 SVLT-delayed (max: 12) M(SD) 7.35 (2.03) 6.86 (2.09) 0.854 0.398 Range 4–11 4–12 Digit span-F (max: 14) M(SD) 10.44 (2.22) 8.95 (2.85) -2.024 0.051 Range 6–14 5–14 Digit span-B (max: 14) M(SD) 7.64 (2.76) 6.20 (2.74) -1.876 0.068 Range 4–14 4–14 Hearing threshold -left ear (dB HL) M(SD) 19 (5.97) 33 (9.05) 6.47 < 0.001 Range 10–41 24–58 Hearing threshold -right ear (dB HL) M(SD) 19 (4.34) 37 (10.59) 7.19 < 0.001 Range 11–28 25–62 Hearing threshold -better ear (dB HL) M(SD) 17 (3.83) 33 (7.90) 8.71 < 0.001 Range 10–24 25–41 M(SD) 3.47 (0.73) 3.25 (0.82) Audiology measurements The data for this study were specifically limited to participants diagnosed with sensorineural hearing loss, which was assessed using with a standard pure-tone audiometry device (AS608 Basic; Interacoustics A/S, Middelfart, Denmark) at audiometric frequencies of 0.5, 1.0, 2.0, and 4.0 kHz. The averaged thresholds were calculated by assigning greater weight to mid-frequencies crucial for speech perception (calculated as: average threshold = (a + 2b + 2c + d) / 6, where a, b, c, and d represent the thresholds at 0.5, 1.0, 2.0, and 4.0 kHz, respectively) 39 . Participants were classified as having HI if their average hearing threshold in the better ear exceeded 25 decibels hearing level (dB HL) 40 , and only those individuals whose hearing threshold differences between the two ears were within 15 dB HL were included. Audiological reports for each group are detailed in Table 2 , with the corresponding audiograms presented in Fig. 1 . Table 2 Audiological details for each group; TH, typical hearing; HI, hearing impairment; SD, standard deviation. Frequency in Hertz Audiometry Group Measure 500 1000 2000 4000 Left Right Left Right Left Right Left Right AS608 TH group ( n = 36) Mean 20 22 17 16 19 18 24 22 Median 20 25 15 15 20 18 22 20 SD 6.87 7.22 6.81 5.41 7.85 7.50 11.7 9.59 Minimum 10 5 10 5 5 5 5 10 Maximum 35 40 40 25 45 45 65 50 HI group ( n = 20) Mean 26 28 28 30 40 39 50 53 Median 25 25 28 27 40 35 48 50 SD 9.45 9.53 9.63 11.5 14.2 17.8 17.5 21.2 Minimum 10 10 15 15 20 10 20 15 Maximum 55 50 55 55 70 80 85 100 Transcutaneous auricular vagus nerve stimulation (taVNS) We administered stimulation using a commercial taVNS device (allearsTM TODOC, Seoul, South Korea) set at 25 Hz frequency, 200 µs pulse width, and a cycle of 30 sec ON and 30 sec OFF was repeated. The intensity of the stimulation was adjusted to 0.5 mA below each participant's pain threshold. The stimulation was calibrated to induce a tingling sensation, indicative of activating the afferent fibers of the auricular vagus nerve 41 , 42 , and was targeted at the cymba concha of the ear, a site known for its strong activation of afferent vagal pathways 43 . The stimulation was applied to either the left or right ear, with counterbalancing across participants. N-back task We conducted n-back tasks targeting two distinct WM domains: verbal vs. visuo-spatial. The verbal n-back task was based on the SemBack version 44 , while the visuo-spatial n-back task was adapted from the study by Christensen and Wright 45 . To manipulate task complexity, we varied the 'n' values (1-back vs. 2-back). The number of task items was matched, with 22 target items out of 73 items in the 1-back condition and 22 targets out of 84 items in the 2-back condition. Each participant engaged in a preparatory block consisting of 10 practice items, including 2 targets, before beginning each n-back task. In the verbal n-back task, each word in written form was presented on the screen, and participants were asked to press the spacebar if the current item belonged to the same semantic category as the item presented 1 or 2 back. The semantic categories included three distinct groups: fruits, animals, and clothes (Supplementary 1). The syllable length and structure in Korean were balanced across the three semantic categories. The visuo-spatial task featured three-dimensional block cubes from Shepard and Metzler 46 , arranged in various configurations across four blocks. Participants were asked to press the spacebar when the current item matched the shape of the block presented 1 or 2 back. All the series of stimuli used in this study were presented visually using PsychoPy 47 on a 39.6 cm laptop screen (Samsung Galaxy Book Pro 39.6 cm Core™ i5), as illustrated in Fig. 2 . Each trial began with the presentation of a fixation cross, which was displayed for 2750 ms, followed by a stimulus presented for 750 ms. Between each stimulus, the fixation cross was consistently displayed for 2750 ms, maintaining a regular interval throughout the experiment. ​ Experimental protocol The study employed a two-session, within-subject, randomized crossover, single-blind, sham-controlled design (as detailed in Fig. 3 ). The two sessions were divided into an active session and a sham session, based on the presence or absence of taVNS stimulation, and the order of stimulation counterbalanced. Participants received both active taVNS and sham stimulation, with each session spaced at least 7 days apart. To ensure consistency, the sessions were preferably conducted at the same time of day. Prior to each session, participants were instructed to refrain from tobacco (2 hours prior), caffeine (6 hours prior), medications, alcohol, and intense physical activity (24 hours prior). To mitigate potential expectation biases, no information was provided regarding the specific stimulation condition administered in each session or its expected effects. The order of the verbal- and visuo-spatial n-back was balanced but consistent for individual participants across both sessions. Upon completing the tasks, stimulation ceased, and participants were given a questionnaire regarding any negative effects resulting from the stimulation. Statistical analysis Statistical analysis was conducted using Python package (v1.2.0). The dependent variables included accuracy (%) and response time (ms). Accuracy (%) was determined by considering trials where participants correctly responded in the n-back tasks. The number of correct responses were divided by the total number of responses (44) per condition, multiplied by 100 to calculate the percentage of correctly responded trials. Response time (RT)—the duration from the presentation of stimuli on the screen to the moment the button was pressed—was measured in milliseconds (ms). Only trials where participants responded correctly to the n-back tasks were included into the RT analyses. For each dependent variable, two-separate four-way mixed-design analyses of variance (ANOVAs) were conducted with group (TH vs. HI), stimulation condition (Sham vs. Active), WM domain (Verbal vs. Visuo-spatial), and task complexity (1-back vs. 2-back) as independent variables. Results Table 3 displays the descriptive statistics of the verbal and visuo-spatial n-back performance for each group, detailing the accuracy (%) and RT (ms). Table 3 Descriptive statistics of the verbal and visuo-spatial n-back performance for each group; TH, typical hearing; HI, hearing impairment; RT, response time; SD, standard deviation. WM domain Verbal Visuo-spatial Task complexity 1-back ( SD ) 2-back ( SD ) 1-back ( SD ) 2-back ( SD ) Accuracy (%) TH group ( n = 36) Active 98.10 (3.61) 86.86 (12.29) 98.10 (3.91) 82.07 (13.24) Sham 98.73 (3.48) 88.38 (10.52) 97.85 (2.93) 82.82 (10.50) HI group ( n = 20) Active 98.86 (2.43) 80 (13.81) 97.95 (3.65) 72.04 (15.23) Sham 98.40 (2.97) 75 (20.95) 95 (6.57) 67.72 (14.07) RT (ms) TH group ( n = 36) Active 843.96 (110.91) 1020.68 (154.95) 774.31 (187.70) 931.35 (171.56) Sham 849.38 (128.33) 1032.44 (160.61) 768.41 (173.57) 918.49 (172.77) HI group ( n = 20) Active 846.02 (110.06) 976.36 (180.03) 708.94 (183.25) 900.08 (161.81) Sham 828.78 (106.83) 927.75 (159.38) 691.10 (135.66) 902.69 (157.64) Accuracy Our analysis revealed significant main effects of group ( F (1,54) = 18.5, p HI group), WM domain ( F (1,54) = 17.2385, p visuo-spatial), and task complexity ( F (1,54) = 206.1979, p 2-back), while stimulation condition did not reach significance ( F (1,54) = 2.6406, p = 0.110). Specifically, the accuracy for the HI group was significantly worse compared to the TH counterparts. Furthermore, the accuracy was significantly lower for visuo-spatial than the verbal WM domain, and for the 2-back compared to the 1-back task. Next, a significant two-way interaction between group (TH vs. HI) and stimulation condition (Active vs. Sham) was observed ( F (1,54) = 6.1515, p = 0.016). This was attributed to the fact that, unlike the TH group (91.28% for active vs. 91.95% for sham), the HI group (87.21% for active vs. 83.63% for sham) showed a significantly improved performance in the active condition compared to the sham condition, see Fig. 4 a. Additionally, a significant two-way interaction was observed between group and task complexity ( F (1,54) = 17.2221, p < 0.001). This interaction stemmed from the HI group displaying significantly lower accuracy compared to the TH group, specifically during the 2-back task (85.03% for TH vs. 73.29% for HI), see Fig. 4 b. Response time In the RT analyses, no significant main effects were observed for group ( F (1,54) = 0.0170, p = 0.897) or stimulation condition ( F (1,54) = 0.7978, p = 0.376). However, significant main effects were found for WM domain ( F (1,54) = 17.8593, p visuo-spatial) and task complexity ( F (1,54) = 135.6700, p < 0.001; 1-back < 2-back), indicating that RTs were significantly longer in the 2-back than the 1-back task, and for verbal compared to visuo-spatial WM domain. Furthermore, a significant two-way interaction was identified between WM domain and task complexity ( F (1,54) = 8.3440, p = 0.006). The two-way interaction was attributed to significant differences in the 1-back condition between the verbal and visuo-spatial WM domain (843.36 ms for verbal vs. 745.88 ms for visuo-spatial) compared to those differences in the 2-back (999.95 ms for verbal vs. 916.51 ms for visuo-spatial) (Fig. 5 ). No other interactions were significant (all p value s > 0.05). Discussion Our findings are in line with previous research on MCI—recognized as an early stage of dementia—where taVNS showed promising improvements in verbal memory functions 18 . Given the limited research on the efficacy of taVNS in aging populations, our exploration serves as an important step in highlighting the clinical potential of taVNS, stressing the need for further exploration into its preventive potential for ARHL as a high-risk group who may be progressing towards dementia. The previous investigations into the impact of taVNS on WM have been limited to specific domains—namely verbal WM 18 or visuo-spatial WM 19 . Our research extends this scope, demonstrating taVNS's efficacy across a wider array of WM domains. The current finding suggests that taVNS enhanced WM performance, particularly in terms of accuracy across the WM domains within the HI group. This indicates that taVNS may exert a similar impact on both verbal and visuo-spatial domains in individuals with ARHL. Further research is necessary to extend these WM enhancement effects after taVNS to a broader range of populations at risk. Another standout in our data is that the significant interaction between group performance and task complexity unveils a clear performance disparity between the HI group and the TH group, especially on the cognitively more challenging 2-back tasks. This distinction is critical as it corroborates the link between ARHL and cognitive decline, aligning with previous studies that have observed differences in n-back task performance among older adults with various cognitive impairments, including MCI 48 , 49 and AD 50 . Further, patients with amnestic MCI (aMCI) showed comparable performance to that of healthy controls in the 1- and 2-back tasks. However, they exhibited inferior discrimination ability in the 3-back task compared to healthy controls 51 . Our research underscores the importance of addressing HI as a modifiable risk factor for cognitive decline in aging populations 1 , 2 . It pinpoints the cognitive domains affected by ARHL, providing a foundation for developing evidence-based interventions and prevention strategies targeting WM enhancements. While the impact of taVNS on the accuracy of WM tasks is evident, RT appears to be relatively unaffected. Our study did not find significant changes in RTs following the application of taVNS. The primary advantage of taVNS, as evidenced in our study, is its significant contribution to boosting decision-making accuracy in WM tasks among older adults with hearing loss. The enhancement in task performance is likely associated with the heightened selective attention induced by taVNS 19 . However, the effects of stimulation did not extend to accelerating processing speed sufficiently to be reflected in reduced RT. This observation aligns with prior research on taVNS/tVNS effects in verbal word order 50 and visuo-spatial 19 memory tasks in healthy individuals, where the improvements were noted in task performance without a reduction in RT. However, a study investigating the effect of taVNS on epilepsy patients demonstrated significant decreases in RT due to taVNS 52 . Highlighting the need for further investigation into the effects of taVNS on processing speed in WM tasks across diverse clinical populations, including ARHL. The suggested directions for future research are as follows: The average hearing loss in the HI group was classified as mild, with levels around 33 dB HL. Notably, the finding that taVNS effectively elicited WM enhancement even at this mild level of hearing loss is particularly significant. It is important to conduct further research to examine the effects of taVNS across a broader spectrum of hearing loss severities, which would be essential to comprehensively understand its efficacy in populations with more severe levels of hearing loss. Secondly, given that our study concentrated on the immediate effects following a single session of taVNS, this presents a clear rationale for initiating intervention studies involving multiple sessions. Such studies should feature extended intervention periods of taVNS treatment to comprehensively evaluate the long-term therapeutic impacts of taVNS. Conclusion The current study provides compelling evidence that individuals with ARHL experience significant memory difficulties in WM tasks compared to those with normal hearing, even when these tasks do not involve auditory challenges. Remarkably, applying taVNS to the HI group led to significant improvements in their WM performance. This finding marks the potential of taVNS as a proactive intervention to counteract cognitive decline, particularly by targeting the decrease in WM capacity linked to hearing loss. Declarations Ethics approval and consent to participate This research was approved by the Institutional Review Board on Human Subjects of Ewha Womans University (No. 2022-0084). Prior to participation, all individuals provided written informed consent. Declaration of generative AI and AI-assisted technologies in the writing process During the preparation of this work the author(s) used [ChatGPT 4.0] to [improve readability and check for grammar corrections]. After using this tool/service, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the publication. Author Contribution Statement Junyoung Shin: Conceptualization, Formal Analysis, Methodology, Visualization, Writing – original draft Shinhee Noh: Data curation, Investigation, Writing – review & editing Jimin Park: Investigation, Writing – review & editing Sang Beom Jun: Conceptualization, Funding acquisition, Supervision, Writing – review & editing Jee Eun Sung: Conceptualization, Funding acquisition, Supervision, Writing – review & editing Funding source This work was partly supported by the National Research Council of Science & Technology (NST) grant by the Korea government (MSIT) (No. CAP21053-000), the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (2022R1A2C2005062) and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2022R1I1A4063209). Conflicts of interest The authors state that they have no known competing financial interests or personal relationships that could appear to have influenced the work presented in this paper. Data availability The datasets used and/or analysed during the current study available from the corresponding author on reasonable request. References Livingston G. et al. Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. Lancet 396 , 413-446. https://doi.org/10.1016/S0140-6736(20)30367-6 (2020). Panza F., Solfrizzi V., & Logroscino G. Age-related hearing impairment-a risk factor and frailty marker for dementia and AD. Nat. Rev. Neurol . 11 , 166-175. https://doi.org/10.1038/nrneurol.2015.12 (2015). Lindenberger U. & Baltes P. B. Sensory functioning and intelligence in old age: A strong connection. Psychol. Aging 9 , 339-355. https://doi.org/10.1037//0882-7974.9.3.339 (1994). Belin P., Zatorre R. J., Hoge R., Evans A. C., & Pike B. 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K., Kwak D. I., Joe S. H., & Lee H. S. A study of standardization of Korean form of geriatric depression scale (KGDS). Geriatr. Psychiatry Med. 1 , 61-72 (1997). Katz, J. (Ed.). Handbook of Clinical Audiology. 7th edn. Wolters Kluwer; Philadelphia, PA (2014). World Health Organization. Report of the informal working group on prevention of deafness and hearing impairment programme planning: Geneva, 18–21 June 1991. World Health Organization, Geneva, Switzerland (1991). Ben-Menachem E., Revesz D., Simon B. J., & Silberstein S. Surgically implanted and non-invasive vagus nerve stimulation: A review of efficacy, safety, and tolerability. Eur. J. Neurol . 22 , 1260-8. https://doi.org/10.1111/ene.12629 (2015). Yuan H. & Silberstein S. D. Vagus nerve and vagus nerve stimulation: a comprehensive review: Part II. Headache 56 , 259-266. https://doi.org/10.1111/head.12650 (2016). Yakunina N., Kim S. S., & Nam E. C. Optimization of transcutaneous vagus nerve stimulation using functional MRI. Neuromodulation 20 , 290-300. https://doi.org/10.1111/ner.12541 (2017). Wright H. H., Downey R. A., Gravier M., Love T., & Shapiro L. P. Processing distinct linguistic information types in working memory in aphasia. Aphasiology 21 , 802-813. https://doi.org/10.1080/02687030701192414 (2007). Christensen S. C. & Wright H. H. Verbal and non-verbal working memory in aphasia: What three n-back tasks reveal. Aphasiology 24 , 752–762. https://doi.org/10.1080/02687030903437690 (2010). Shepard R. N. & Metzler J. Mental rotation of three-dimensional objects. Science 171 , 701-703. https://doi.org/10.1126/science.171.3972.701 (1971). Peirce, J. W. PsychoPy—psychophysics software in Python. J. Neurosci. Methods 162 , 8–13 (2007). Borkowska A., Drozdz W., Jurkowski P., & Rybakowski J. K. The Wisconsin Card Sorting Test and the N-back test in mild cognitive impairment and elderly depression. World J. Biol. Psychiatry 10 , 870-6. https://doi.org/10.1080/15622970701557985 (2009). Guild E. B., Vasquez B. P., Maione A. M., Mah L., Ween J., & Anderson N. D. Dynamic working memory performance in individuals with single-domain amnestic mild cognitive impairment. J. Clin. Exp. Neuropsychol . 36 , 751-60. https://doi.org/10.1080/13803395.2014.941790 (2014). Fraga F. J., Mamani G. Q., Johns E., Tavares G., Falk T. H., & Phillips N. A. Early diagnosis of mild cognitive impairment and Alzheimer's with event-related potentials and event-related desynchronization in N-back working memory tasks. Comput. Methods Programs Biomed. 164 , 1-13. https://doi.org/10.1016/j.cmpb.2018.06.011 (2018). Kaan E., De Aguiar I., Clarke C., Lamb D. G., Williamson J. B., & Porges E. C. A transcutaneous vagus nerve stimulation study on verbal order memory. Neurolinguistics 59 , 100990. https://doi.org/10.1016/j.jneuroling.2021.100990 (2021). Pan L., Wang J., Wu W., Wang Y., Zhu Y., & Song Y. Transcutaneous auricular vagus nerve stimulation improves working memory in temporal lobe epilepsy: A randomized double‐blind study. CNS Neurosci. Ther. 30 , e14395. https://doi.org/10.1111/cns.14395 (2024). Additional Declarations No competing interests reported. Supplementary Files Supplementary1.docx Cite Share Download PDF Status: Published Journal Publication published 22 Jul, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 07 May, 2025 Reviews received at journal 03 May, 2025 Reviews received at journal 23 Apr, 2025 Reviewers agreed at journal 23 Apr, 2025 Reviews received at journal 21 Apr, 2025 Reviewers agreed at journal 07 Apr, 2025 Reviewers agreed at journal 07 Apr, 2025 Reviewers invited by journal 02 Sep, 2024 Editor assigned by journal 02 Sep, 2024 Editor invited by journal 02 Sep, 2024 Submission checks completed at journal 30 Aug, 2024 First submitted to journal 30 Aug, 2024 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. 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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-5002507","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":350858922,"identity":"314e16ec-cb0d-4d43-91ac-be085d9fa28a","order_by":0,"name":"Junyoung Shin","email":"","orcid":"","institution":"Ewha Womans University","correspondingAuthor":false,"prefix":"","firstName":"Junyoung","middleName":"","lastName":"Shin","suffix":""},{"id":350858923,"identity":"44efa63e-d9d1-4076-a37b-52984f81eca3","order_by":1,"name":"Shinhee Noh","email":"","orcid":"","institution":"Ewha Womans University","correspondingAuthor":false,"prefix":"","firstName":"Shinhee","middleName":"","lastName":"Noh","suffix":""},{"id":350858924,"identity":"d122f216-e38b-474d-a449-50fa530bcde9","order_by":2,"name":"Jimin Park","email":"","orcid":"","institution":"Ewha Womans University","correspondingAuthor":false,"prefix":"","firstName":"Jimin","middleName":"","lastName":"Park","suffix":""},{"id":350858925,"identity":"2effeef7-ecea-47cc-b013-6cabc7392794","order_by":3,"name":"Sang Beom Jun","email":"","orcid":"","institution":"Ewha Womans University","correspondingAuthor":false,"prefix":"","firstName":"Sang","middleName":"Beom","lastName":"Jun","suffix":""},{"id":350858926,"identity":"23d36e69-aa2c-4479-a318-3ca220613c6c","order_by":4,"name":"Jee Eun Sung","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2ElEQVRIiWNgGAWjYBACxgYILcfAwANhSRCrxZh4LTCQ2EC0Fub25sOfeXfUpvdL5B78wFBjxyA5+wABh/UcS5PmPXM8d+aMvGQJhmPJDNJ8CQS0zMgxY+ZtO5a74XaOgQQD2wEGOR4CDmOc//7zZ6CWdPvbOcY/GP4Ro2UGD4M0b1tNgoF0jpkEY9sBBmmCWnrSzCTnth0wnHH/jZlFYl8yj2QPAS2G7Ycff3jbVifP33PG+MaHb3ZyEmcIaWkAU4chvAR4hOIB8hCqjqDCUTAKRsEoGMEAAIzEPe2k21hOAAAAAElFTkSuQmCC","orcid":"","institution":"Ewha Womans University","correspondingAuthor":true,"prefix":"","firstName":"Jee","middleName":"Eun","lastName":"Sung","suffix":""}],"badges":[],"createdAt":"2024-08-30 08:53:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5002507/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5002507/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-11363-6","type":"published","date":"2025-07-22T15:57:44+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":66940721,"identity":"a5b3a866-26e9-4b33-a725-58ed1462a7c9","added_by":"auto","created_at":"2024-10-18 08:52:49","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":137883,"visible":true,"origin":"","legend":"\u003cp\u003eAudiograms of air conduction hearing thresholds in hearing impairment and typical hearing groups.\u003c/p\u003e","description":"","filename":"Fig1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5002507/v1/3ef871cab920e9d8c62d65e0.jpg"},{"id":66938208,"identity":"ab4a2e42-a959-45ff-8b28-57836594ee18","added_by":"auto","created_at":"2024-10-18 08:36:49","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":65169,"visible":true,"origin":"","legend":"\u003cp\u003eExperimental procedures of n-back tasks. a. verbal 1-back; b. visuo-spatial 1-back; c. verbal 2-back; d. visuo-spatial 2-back.\u003c/p\u003e","description":"","filename":"Fig2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5002507/v1/4e3d5d29822ecfa9a531f03b.jpg"},{"id":66938212,"identity":"59fce685-c072-466d-8541-f9ad96a7a7ee","added_by":"auto","created_at":"2024-10-18 08:36:49","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":61721,"visible":true,"origin":"","legend":"\u003cp\u003eExperimental protocol for each session depending on stimulation condition. In the sham session (a), stimulation was administered for 30 seconds at the beginning and end of the session. During the active session (b), participants underwent a 15-minute pre-stimulation phase, and then received stimulation until they completed the n-back tasks (20 min), totaling approximately 35 minutes of stimulation.\u003c/p\u003e","description":"","filename":"Fig3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5002507/v1/4dda6906ac2fafae194fb453.jpg"},{"id":66938207,"identity":"4bbc6dbd-c7d0-49ed-a264-710729c5cddf","added_by":"auto","created_at":"2024-10-18 08:36:49","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":63533,"visible":true,"origin":"","legend":"\u003cp\u003eAccuracy (in percent) by (a) group × stimulation condition and (b) task complexity × group. Error bars indicate group mean ± standard deviations (SD).\u003c/p\u003e","description":"","filename":"Fig4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5002507/v1/a50220789645249d83542a2f.jpg"},{"id":66938213,"identity":"80091dd3-1d7c-498c-a202-09a129e71b45","added_by":"auto","created_at":"2024-10-18 08:36:49","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":70203,"visible":true,"origin":"","legend":"\u003cp\u003eResponse time (in millisecond) by task complexities × working memory domains. Error bars indicate group mean ± standard deviations (SD).\u003c/p\u003e","description":"","filename":"Fig5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5002507/v1/9d308e1b3c3a6693112efc0d.jpg"},{"id":87756843,"identity":"1dbf254a-97f8-4b73-87c6-2d246aab1074","added_by":"auto","created_at":"2025-07-28 16:09:38","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1248977,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5002507/v1/c567dcd6-889e-4a3f-a485-6fe4bd4a2b3c.pdf"},{"id":66938210,"identity":"78fed697-90c0-4d47-8a13-0a2fa4bd6e37","added_by":"auto","created_at":"2024-10-18 08:36:49","extension":"docx","order_by":7,"title":"","display":"","copyAsset":false,"role":"supplement","size":14944,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementary1.docx","url":"https://assets-eu.researchsquare.com/files/rs-5002507/v1/afe2748a469d45bb61083392.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Transcutaneous Auricular Vagus Nerve Stimulation Enhanced Working Memory in Older Adults with Age-Related Hearing Loss","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDuring the advanced stages of human aging, individuals typically encounter a range of physical and cognitive deteriorations. These changes include modifications in the structural and functional aspects of the auditory system. Consistent evidence from epidemiological studies strongly links sensory loss related to hearing with an elevated risk of developing dementia\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e, with this link becoming more pronounced with age\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. The deprivation hypothesis, proposed by Baltes and Lindenberger\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e, has gained substantial support in explaining these connections\u003csup\u003e\u003cspan additionalcitationids=\"CR5 CR6\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. It posits that prolonged periods of reduced auditory input over time due to untreated hearing impairment (HI) can lead to alterations in neural networks, subsequently affecting cognition and processing speed\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. Overall, older adults with HI are now identified as preventative clinical populations in need of early cognitive interventions, given their demonstrated cognitive deficits relative to those with normal hearing\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eNoninvasive brain stimulation, particularly transcutaneous auricular vagus nerve stimulation (taVNS), has garnered recognition for modulating cognition by targeting the auricular branch of the vagus nerve. Research has covered various cognitive domains through taVNS, such as executive functions\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e, and inhibitory controls\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e, with notable improvements on memory functions\u003csup\u003e\u003cspan additionalcitationids=\"CR14 CR15 CR16 CR17\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. A recent study highlighted its potential to improve working memory (WM), particularly in the visuo-spatial n-back task performance, within a cohort of healthy young adults aged 18 to 23 years\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. Further, patients with mild cognitive impairment (MCI) exhibited notable improvements in verbal memory functions, including both immediate and delayed recalls, following a 24-week intervention of taVNS\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. These studies highlight taVNS as a promising noninvasive approach for improving memory issues and potentially mitigating cognitive decline associated with aging.\u003c/p\u003e \u003cp\u003eRecent studies are increasingly focusing on the link between cognitive decline and age-related hearing loss (ARHL), especially utilizing WM tasks to explore this relationship\u003csup\u003e\u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. Previously, a marked correlation was observed between hearing ability, as indexed by peripheral auditory thresholds, and WM functioning in a group of 156 individuals aged 70 and above\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. This study highlighted early markers and intervention points for cognitive decline with a specific emphasis on hearing loss in older adults as a possible precursor to dementia. More recently, an EEG study identified this connection by examining the association between hearing loss and WM functions, finding significant correlations between auditory P300 latency and WM capacity in individuals with HI\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. Subsequent studies have further supported the idea that impaired hearing can significantly contribute to the deterioration of WM capacity\u003csup\u003e\u003cspan additionalcitationids=\"CR25\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e, suggesting that addressing ARHL early on could be a key intervention point for preventing cognitive decline.\u003c/p\u003e \u003cp\u003eExtensive research on WM indicates that the specific domains and components of WM being targeted are considered critical when selecting WM tasks to examine individual differences in WM capacity\u003csup\u003e\u003cspan additionalcitationids=\"CR28\" citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. For instance, in WM capacity across verbal and visuo-spatial domains, a study utilizing the digit and corsi span forward tests among patients in the early stages of Alzheimer's disease (AD) and healthy control subjects found a significant decline in the visuo-spatial WM domain among mild AD patients\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. However, the differences between these patients and the control group in the digit span test were minimal. These findings highlight the significance of considering distinct WM domains of incoming information when evaluating WM capacity, particularly evident in cognitively impaired older adults\u003csup\u003e\u003cspan additionalcitationids=\"CR32\" citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eEvidence from older adults with ARHL suggests that performance differences emerge depending on the WM task types, such as those in the verbal and visuo-spatial domains\u003csup\u003e\u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. Some studies employed verbal WM tasks\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e, while others focused on the visuo-spatial domains of WM when studying older adults with ARHL\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. The study, which examined the association between hearing ability and cognitive functions among older individuals with and without ARHL, focused on the verbal WM domain using the n-back task with letter presentation. It found that individuals with HI exhibited significantly slower reaction times and fewer correct responses on the 2-back task, although no substantial group differences were observed on the 0-back task\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e. Another group of researchers reported that individuals with HI exhibit WM deficits in the visuo-spatial domain, even in the absence of specific auditory challenges\u003csup\u003e\u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e. Despite the increasing research on WM deficits for older adults with ARHL, there have been no effort yet to apply the taVNS to improve WM functions for populations at risk of dementia due to ARHL. The current study aims to investigate the effects of taVNS on WM performance by systematically manipulating task complexity (1-back vs. 2-back) and WM domain (verbal vs. visuo-spatial). To the best of our knowledge, this represents the first attempt to examine these effects specifically in older adults with ARHL, a group in need of early cognitive intervention.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eParticipants\u003c/p\u003e \u003cp\u003e The study involved 56 participants aged over 60 years, consisting of 20 individuals with HI and 36 typical hearing (TH). All participants, who were native Korean speakers, met the following criteria: they obtained scores within normal ranges on the Korean version of the mini mental state examination (K-MMSE)\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e, the Seoul verbal learning test (SVLT), the digit span tests from the standardized Seoul neuropsychological screening battery-II\u003csup\u003e\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e, and a short version of the geriatric depression scale (\u0026lt;\u0026thinsp;8 out of 15)\u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e. None of the participants reported any visual impairments, learning difficulties, or a history of brain injuries.\u003c/p\u003e \u003cp\u003e All experiments were conducted in accordance with relevant guidelines and regulations. This research was approved by the Institutional Review Board on Human Subjects of Ewha Womans University (Approval No. 2022-0084), and all procedures were performed following ethical standards and institutional policies. Prior to participation, all individuals provided written informed consent.\u003c/p\u003e \u003cp\u003eAn independent sample t-test was conducted, revealing no statistically significant differences in age, education years, or screening results of neuropsychological tests between the TH and HI groups (all \u003cem\u003ep-values\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Detailed demographic information and descriptive statistics are provided in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eParticipants\u0026rsquo; descriptive information and screening results of neuropsychological tests; TH, Typical hearing; HI, Hearing impairment; M(SD), mean(standard deviation); K-MMSE, Korean version of the mini-mental state examination; SVLT-imme., Seoul verbal learning test - immediate recall; SVLT-delayed, Seoul verbal learning test - delayed recall; Digit span-F, Digit span test forward; Digit span-B, Digit span test backward; dB HL, decibels hearing level.\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=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTH Group\u003c/p\u003e \u003cp\u003e\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;36\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHI Group\u003c/p\u003e \u003cp\u003e\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;20\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eTest statistics\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003ep-value\u003c/em\u003e\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\u003eGender\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23 (63.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14 (70%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13 (36.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6 (30%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003cp\u003e(years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM(SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e64.03 (3.72)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e65.55 (3.66)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e1.481\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.146\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRange\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e60\u0026ndash;72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e60\u0026ndash;72\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eEducation\u003c/p\u003e \u003cp\u003e(years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM(SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14.56 (2.97)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13.95 (3.18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e-0.698\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.490\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRange\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9\u0026ndash;23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9\u0026ndash;23\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eK-MMSE\u003c/p\u003e \u003cp\u003e(max: 30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM(SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28.97 (1.36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e28.75 (0.96)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e-0.709\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.482\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRange\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e26\u0026ndash;30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e26\u0026ndash;30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSVLT-imme.\u003c/p\u003e \u003cp\u003e(max: 36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM(SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21.28 (3.74)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20.45 (3.84)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e-0.780\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.440\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRange\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15\u0026ndash;31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15\u0026ndash;30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSVLT-delayed\u003c/p\u003e \u003cp\u003e(max: 12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM(SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.35 (2.03)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.86 (2.09)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.854\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.398\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRange\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u0026ndash;11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u0026ndash;12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eDigit span-F\u003c/p\u003e \u003cp\u003e(max: 14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM(SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10.44 (2.22)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.95 (2.85)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e-2.024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.051\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRange\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u0026ndash;14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5\u0026ndash;14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eDigit span-B\u003c/p\u003e \u003cp\u003e(max: 14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM(SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.64 (2.76)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.20 (2.74)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e-1.876\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.068\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRange\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u0026ndash;14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u0026ndash;14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eHearing threshold\u003c/p\u003e \u003cp\u003e-left ear\u003c/p\u003e \u003cp\u003e(dB HL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM(SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19 (5.97)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e33 (9.05)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e6.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRange\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10\u0026ndash;41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e24\u0026ndash;58\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eHearing threshold\u003c/p\u003e \u003cp\u003e-right ear\u003c/p\u003e \u003cp\u003e(dB HL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM(SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19 (4.34)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e37 (10.59)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e7.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRange\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11\u0026ndash;28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25\u0026ndash;62\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eHearing threshold\u003c/p\u003e \u003cp\u003e-better ear\u003c/p\u003e \u003cp\u003e(dB HL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM(SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17 (3.83)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e33 (7.90)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e8.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRange\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10\u0026ndash;24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25\u0026ndash;41\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eM(SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.47 (0.73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.25 (0.82)\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\u003eAudiology measurements\u003c/p\u003e \u003cp\u003eThe data for this study were specifically limited to participants diagnosed with sensorineural hearing loss, which was assessed using with a standard pure-tone audiometry device (AS608 Basic; Interacoustics A/S, Middelfart, Denmark) at audiometric frequencies of 0.5, 1.0, 2.0, and 4.0 kHz. The averaged thresholds were calculated by assigning greater weight to mid-frequencies crucial for speech perception (calculated as: average threshold = (a\u0026thinsp;+\u0026thinsp;2b\u0026thinsp;+\u0026thinsp;2c\u0026thinsp;+\u0026thinsp;d) / 6, where a, b, c, and d represent the thresholds at 0.5, 1.0, 2.0, and 4.0 kHz, respectively)\u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e. Participants were classified as having HI if their average hearing threshold in the better ear exceeded 25 decibels hearing level (dB HL) \u003csup\u003e\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e, and only those individuals whose hearing threshold differences between the two ears were within 15 dB HL were included. Audiological reports for each group are detailed in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, with the corresponding audiograms presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\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\u003eAudiological details for each group; TH, typical hearing; HI, hearing impairment; SD, standard deviation.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"11\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"8\" nameend=\"c11\" namest=\"c4\"\u003e \u003cp\u003eFrequency in Hertz\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\u003eAudiometry\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eGroup\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eMeasure\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e\u003cem\u003e500\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e\u003cem\u003e1000\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003e\u003cem\u003e2000\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003e\u003cem\u003e4000\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLeft\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eLeft\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eRight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eLeft\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eRight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eLeft\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003eRight\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"9\" rowspan=\"10\"\u003e \u003cp\u003eAS608\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003eTH\u003c/p\u003e \u003cp\u003egroup\u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMedian\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e7.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e11.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e9.59\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMinimum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5\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\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMaximum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003eHI\u003c/p\u003e \u003cp\u003egroup\u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e53\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMedian\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e9.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e11.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e14.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e17.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e17.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e21.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMinimum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMaximum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e100\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\u003eTranscutaneous auricular vagus nerve stimulation (taVNS)\u003c/p\u003e \u003cp\u003eWe administered stimulation using a commercial taVNS device (allearsTM TODOC, Seoul, South Korea) set at 25 Hz frequency, 200 \u0026micro;s pulse width, and a cycle of 30 sec ON and 30 sec OFF was repeated. The intensity of the stimulation was adjusted to 0.5 mA below each participant's pain threshold. The stimulation was calibrated to induce a tingling sensation, indicative of activating the afferent fibers of the auricular vagus nerve\u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e\u003c/sup\u003e, and was targeted at the cymba concha of the ear, a site known for its strong activation of afferent vagal pathways\u003csup\u003e\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e. The stimulation was applied to either the left or right ear, with counterbalancing across participants.\u003c/p\u003e \u003cp\u003eN-back task\u003c/p\u003e \u003cp\u003e We conducted n-back tasks targeting two distinct WM domains: verbal vs. visuo-spatial. The verbal n-back task was based on the SemBack version\u003csup\u003e\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u003c/sup\u003e, while the visuo-spatial n-back task was adapted from the study by Christensen and Wright\u003csup\u003e\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e\u003c/sup\u003e. To manipulate task complexity, we varied the 'n' values (1-back vs. 2-back). The number of task items was matched, with 22 target items out of 73 items in the 1-back condition and 22 targets out of 84 items in the 2-back condition. Each participant engaged in a preparatory block consisting of 10 practice items, including 2 targets, before beginning each n-back task.\u003c/p\u003e \u003cp\u003e In the verbal n-back task, each word in written form was presented on the screen, and participants were asked to press the spacebar if the current item belonged to the same semantic category as the item presented 1 or 2 back. The semantic categories included three distinct groups: fruits, animals, and clothes (Supplementary 1). The syllable length and structure in Korean were balanced across the three semantic categories.\u003c/p\u003e \u003cp\u003eThe visuo-spatial task featured three-dimensional block cubes from Shepard and Metzler\u003csup\u003e\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e\u003c/sup\u003e, arranged in various configurations across four blocks. Participants were asked to press the spacebar when the current item matched the shape of the block presented 1 or 2 back.\u003c/p\u003e \u003cp\u003eAll the series of stimuli used in this study were presented visually using PsychoPy\u003csup\u003e\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e\u003c/sup\u003e on a 39.6 cm laptop screen (Samsung Galaxy Book Pro 39.6 cm Core\u0026trade; i5), as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Each trial began with the presentation of a fixation cross, which was displayed for 2750 ms, followed by a stimulus presented for 750 ms. Between each stimulus, the fixation cross was consistently displayed for 2750 ms, maintaining a regular interval throughout the experiment.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e​\u003c/h2\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eExperimental protocol\u003c/p\u003e \u003cp\u003eThe study employed a two-session, within-subject, randomized crossover, single-blind, sham-controlled design (as detailed in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The two sessions were divided into an active session and a sham session, based on the presence or absence of taVNS stimulation, and the order of stimulation counterbalanced. Participants received both active taVNS and sham stimulation, with each session spaced at least 7 days apart. To ensure consistency, the sessions were preferably conducted at the same time of day.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003ePrior to each session, participants were instructed to refrain from tobacco (2 hours prior), caffeine (6 hours prior), medications, alcohol, and intense physical activity (24 hours prior). To mitigate potential expectation biases, no information was provided regarding the specific stimulation condition administered in each session or its expected effects.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e The order of the verbal- and visuo-spatial n-back was balanced but consistent for individual participants across both sessions. Upon completing the tasks, stimulation ceased, and participants were given a questionnaire regarding any negative effects resulting from the stimulation.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eStatistical analysis was conducted using Python package (v1.2.0). The dependent variables included accuracy (%) and response time (ms). Accuracy (%) was determined by considering trials where participants correctly responded in the n-back tasks. The number of correct responses were divided by the total number of responses (44) per condition, multiplied by 100 to calculate the percentage of correctly responded trials. Response time (RT)\u0026mdash;the duration from the presentation of stimuli on the screen to the moment the button was pressed\u0026mdash;was measured in milliseconds (ms). Only trials where participants responded correctly to the n-back tasks were included into the RT analyses.\u003c/p\u003e \u003cp\u003eFor each dependent variable, two-separate four-way mixed-design analyses of variance (ANOVAs) were conducted with group (TH vs. HI), stimulation condition (Sham vs. Active), WM domain (Verbal vs. Visuo-spatial), and task complexity (1-back vs. 2-back) as independent variables.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e displays the descriptive statistics of the verbal and visuo-spatial n-back performance for each group, detailing the accuracy (%) and RT (ms).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDescriptive statistics of the verbal and visuo-spatial n-back performance for each group; TH, typical hearing; HI, hearing impairment; RT, response time; SD, standard deviation.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\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=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e \u003cp\u003eWM domain\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eVerbal\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003eVisuo-spatial\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e \u003cp\u003eTask complexity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1-back (\u003cem\u003eSD\u003c/em\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2-back (\u003cem\u003eSD\u003c/em\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1-back (\u003cem\u003eSD\u003c/em\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2-back (\u003cem\u003eSD\u003c/em\u003e)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eAccuracy\u003c/p\u003e \u003cp\u003e(%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTH\u003c/p\u003e \u003cp\u003egroup\u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eActive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98.10 (3.61)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e86.86 (12.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e98.10 (3.91)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e82.07 (13.24)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSham\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98.73 (3.48)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e88.38 (10.52)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e97.85 (2.93)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e82.82 (10.50)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eHI\u003c/p\u003e \u003cp\u003egroup\u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eActive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98.86 (2.43)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e80 (13.81)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e97.95 (3.65)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e72.04 (15.23)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSham\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e98.40 (2.97)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e75 (20.95)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e95 (6.57)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e67.72 (14.07)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eRT (ms)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTH\u003c/p\u003e \u003cp\u003egroup\u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eActive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e843.96 (110.91)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1020.68 (154.95)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e774.31 (187.70)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e931.35 (171.56)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSham\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e849.38 (128.33)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1032.44 (160.61)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e768.41 (173.57)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e918.49 (172.77)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eHI\u003c/p\u003e \u003cp\u003egroup\u003c/p\u003e \u003cp\u003e(\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eActive\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e846.02 (110.06)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e976.36 (180.03)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e708.94 (183.25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e900.08 (161.81)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSham\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e828.78 (106.83)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e927.75 (159.38)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e691.10 (135.66)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e902.69 (157.64)\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\u003eAccuracy\u003c/p\u003e \u003cp\u003eOur analysis revealed significant main effects of group (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e(1,54)\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;18.5, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001; TH group\u0026thinsp;\u0026gt;\u0026thinsp;HI group), WM domain (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e(1,54)\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;17.2385, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001; verbal\u0026thinsp;\u0026gt;\u0026thinsp;visuo-spatial), and task complexity (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e(1,54)\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;206.1979, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001; 1-back\u0026thinsp;\u0026gt;\u0026thinsp;2-back), while stimulation condition did not reach significance (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e(1,54)\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;2.6406, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.110). Specifically, the accuracy for the HI group was significantly worse compared to the TH counterparts. Furthermore, the accuracy was significantly lower for visuo-spatial than the verbal WM domain, and for the 2-back compared to the 1-back task.\u003c/p\u003e \u003cp\u003eNext, a significant two-way interaction between group (TH vs. HI) and stimulation condition (Active vs. Sham) was observed (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e(1,54)\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;6.1515, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.016). This was attributed to the fact that, unlike the TH group (91.28% for active vs. 91.95% for sham), the HI group (87.21% for active vs. 83.63% for sham) showed a significantly improved performance in the active condition compared to the sham condition, see Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003ea.\u003c/p\u003e \u003cp\u003eAdditionally, a significant two-way interaction was observed between group and task complexity (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e(1,54)\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;17.2221, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). This interaction stemmed from the HI group displaying significantly lower accuracy compared to the TH group, specifically during the 2-back task (85.03% for TH vs. 73.29% for HI), see Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003eb.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eResponse time\u003c/p\u003e \u003cp\u003eIn the RT analyses, no significant main effects were observed for group (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e(1,54)\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;0.0170, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.897) or stimulation condition (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e(1,54)\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;0.7978, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.376). However, significant main effects were found for WM domain (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e(1,54)\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;17.8593, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001; verbal\u0026thinsp;\u0026gt;\u0026thinsp;visuo-spatial) and task complexity (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e(1,54)\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;135.6700, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001; 1-back\u0026thinsp;\u0026lt;\u0026thinsp;2-back), indicating that RTs were significantly longer in the 2-back than the 1-back task, and for verbal compared to visuo-spatial WM domain.\u003c/p\u003e \u003cp\u003eFurthermore, a significant two-way interaction was identified between WM domain and task complexity (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e(1,54)\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;8.3440, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.006). The two-way interaction was attributed to significant differences in the 1-back condition between the verbal and visuo-spatial WM domain (843.36 ms for verbal vs. 745.88 ms for visuo-spatial) compared to those differences in the 2-back (999.95 ms for verbal vs. 916.51 ms for visuo-spatial) (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e5\u003c/span\u003e). No other interactions were significant (all \u003cem\u003ep value\u003c/em\u003es\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eOur findings are in line with previous research on MCI\u0026mdash;recognized as an early stage of dementia\u0026mdash;where taVNS showed promising improvements in verbal memory functions\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. Given the limited research on the efficacy of taVNS in aging populations, our exploration serves as an important step in highlighting the clinical potential of taVNS, stressing the need for further exploration into its preventive potential for ARHL as a high-risk group who may be progressing towards dementia.\u003c/p\u003e \u003cp\u003eThe previous investigations into the impact of taVNS on WM have been limited to specific domains\u0026mdash;namely verbal WM\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e or visuo-spatial WM\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. Our research extends this scope, demonstrating taVNS's efficacy across a wider array of WM domains. The current finding suggests that taVNS enhanced WM performance, particularly in terms of accuracy across the WM domains within the HI group. This indicates that taVNS may exert a similar impact on both verbal and visuo-spatial domains in individuals with ARHL. Further research is necessary to extend these WM enhancement effects after taVNS to a broader range of populations at risk.\u003c/p\u003e \u003cp\u003eAnother standout in our data is that the significant interaction between group performance and task complexity unveils a clear performance disparity between the HI group and the TH group, especially on the cognitively more challenging 2-back tasks. This distinction is critical as it corroborates the link between ARHL and cognitive decline, aligning with previous studies that have observed differences in n-back task performance among older adults with various cognitive impairments, including MCI\u003csup\u003e\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e\u003c/sup\u003e and AD\u003csup\u003e\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e\u003c/sup\u003e. Further, patients with amnestic MCI (aMCI) showed comparable performance to that of healthy controls in the 1- and 2-back tasks. However, they exhibited inferior discrimination ability in the 3-back task compared to healthy controls\u003csup\u003e\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e\u003c/sup\u003e. Our research underscores the importance of addressing HI as a modifiable risk factor for cognitive decline in aging populations\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. It pinpoints the cognitive domains affected by ARHL, providing a foundation for developing evidence-based interventions and prevention strategies targeting WM enhancements.\u003c/p\u003e \u003cp\u003eWhile the impact of taVNS on the accuracy of WM tasks is evident, RT appears to be relatively unaffected. Our study did not find significant changes in RTs following the application of taVNS. The primary advantage of taVNS, as evidenced in our study, is its significant contribution to boosting decision-making accuracy in WM tasks among older adults with hearing loss. The enhancement in task performance is likely associated with the heightened selective attention induced by taVNS\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. However, the effects of stimulation did not extend to accelerating processing speed sufficiently to be reflected in reduced RT. This observation aligns with prior research on taVNS/tVNS effects in verbal word order\u003csup\u003e\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e\u003c/sup\u003e and visuo-spatial\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e memory tasks in healthy individuals, where the improvements were noted in task performance without a reduction in RT. However, a study investigating the effect of taVNS on epilepsy patients demonstrated significant decreases in RT due to taVNS\u003csup\u003e\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e\u003c/sup\u003e. Highlighting the need for further investigation into the effects of taVNS on processing speed in WM tasks across diverse clinical populations, including ARHL.\u003c/p\u003e \u003cp\u003eThe suggested directions for future research are as follows: The average hearing loss in the HI group was classified as mild, with levels around 33 dB HL. Notably, the finding that taVNS effectively elicited WM enhancement even at this mild level of hearing loss is particularly significant. It is important to conduct further research to examine the effects of taVNS across a broader spectrum of hearing loss severities, which would be essential to comprehensively understand its efficacy in populations with more severe levels of hearing loss. Secondly, given that our study concentrated on the immediate effects following a single session of taVNS, this presents a clear rationale for initiating intervention studies involving multiple sessions. Such studies should feature extended intervention periods of taVNS treatment to comprehensively evaluate the long-term therapeutic impacts of taVNS.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe current study provides compelling evidence that individuals with ARHL experience significant memory difficulties in WM tasks compared to those with normal hearing, even when these tasks do not involve auditory challenges. Remarkably, applying taVNS to the HI group led to significant improvements in their WM performance. This finding marks the potential of taVNS as a proactive intervention to counteract cognitive decline, particularly by targeting the decrease in WM capacity linked to hearing loss.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research was approved by the Institutional Review Board on Human Subjects of Ewha Womans University (No. 2022-0084). Prior to participation, all individuals provided written informed consent.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eDeclaration of generative AI and AI-assisted technologies in the writing process\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDuring the preparation of this work the author(s) used [ChatGPT 4.0] to [improve readability and check for grammar corrections]. After using this tool/service, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eAuthor Contribution Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eJunyoung Shin: Conceptualization, Formal Analysis, Methodology, Visualization, Writing \u0026ndash; original draft\u003c/p\u003e\n\u003cp\u003eShinhee Noh: Data curation, Investigation, Writing \u0026ndash; review \u0026amp; editing\u003c/p\u003e\n\u003cp\u003eJimin Park: Investigation, Writing \u0026ndash; review \u0026amp; editing\u003c/p\u003e\n\u003cp\u003eSang Beom Jun: Conceptualization, Funding acquisition, Supervision, Writing \u0026ndash; review \u0026amp; editing\u003c/p\u003e\n\u003cp\u003eJee Eun Sung: Conceptualization, Funding acquisition, Supervision, Writing \u0026ndash; review \u0026amp; editing\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eFunding source\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was\u0026nbsp;partly supported by the National Research Council of Science \u0026amp; Technology (NST) grant by the Korea government (MSIT) (No. CAP21053-000), the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (2022R1A2C2005062) and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2022R1I1A4063209).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eConflicts of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors state that they have no known competing financial interests or personal relationships that could appear to have influenced the work presented in this paper.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eData availability\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study available from \u003cstrong\u003ethe corresponding author on reasonable request.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col start=\"1\" type=\"1\"\u003e\n\u003cli\u003eLivingston G. et al. 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Ther.\u003c/em\u003e \u003cstrong\u003e30\u003c/strong\u003e, e14395. https://doi.org/10.1111/cns.14395 (2024).\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":"Age-related hearing loss, Cognitive intervention, Transcutaneous auricular vagus nerve stimulation, Working memory, N-back task","lastPublishedDoi":"10.21203/rs.3.rs-5002507/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5002507/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eAge-related hearing loss (ARHL) is associated with an increased risk of dementia, necessitating early cognitive interventions to prevent further cognitive decline. Despite promising evidence supporting transcutaneous auricular vagus nerve stimulation (taVNS) for mitigating cognitive impairment, its impact on working memory (WM) in older adults with ARHL is unexplored. This study is the first attempt to investigate taVNS effects on WM in the older adults with hearing impairment (HI) and with typical hearing (TH). WM capacity was assessed using n-back tasks, varying by WM domains (verbal and visuo-spatial) and complexity levels (1-back and 2-back). Participants underwent a two-session, within-subjects, randomized crossover, single-blind sham-controlled protocol, receiving 20 minutes of continuous stimulation in the active session, whereas only 30 seconds at the start and end in the sham session. The HI group performed significantly worse than the TH group on the 2-back tasks. Within the HI group, taVNS significantly enhanced performance across all WM domains and complexity levels compared to the sham condition. These findings suggest that taVNS enhances WM in hearing-impaired older adults, underscoring its potential as a clinical intervention for addressing WM challenges associated with ARHL.\u003c/p\u003e","manuscriptTitle":"Transcutaneous Auricular Vagus Nerve Stimulation Enhanced Working Memory in Older Adults with Age-Related Hearing Loss","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-10-18 08:36:44","doi":"10.21203/rs.3.rs-5002507/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-05-07T09:04:06+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-03T09:34:15+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-23T10:38:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"137653575240985002726859460962291622521","date":"2025-04-23T05:42:38+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-21T09:24:51+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"246175223458501429014608910814959316343","date":"2025-04-08T02:24:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"13532869423829412586330499428369585201","date":"2025-04-07T14:19:31+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-09-02T14:20:09+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-09-02T14:18:38+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-09-02T14:10:28+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-08-30T09:20:56+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2024-08-30T08:50:35+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":"a7938b10-59ce-4dd7-99b8-d7a63390dc48","owner":[],"postedDate":"October 18th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-07-28T16:05:29+00:00","versionOfRecord":{"articleIdentity":"rs-5002507","link":"https://doi.org/10.1038/s41598-025-11363-6","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-07-22 15:57:44","publishedOnDateReadable":"July 22nd, 2025"},"versionCreatedAt":"2024-10-18 08:36:44","video":"","vorDoi":"10.1038/s41598-025-11363-6","vorDoiUrl":"https://doi.org/10.1038/s41598-025-11363-6","workflowStages":[]},"version":"v1","identity":"rs-5002507","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5002507","identity":"rs-5002507","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}