Comparison of IOPI Use Technique under Two Different Conditions for Measuring Oropharyngeal Swallowing Pressure, Tongue Strength and Endurance in Healthy Young Adults.

Comparison of IOPI Use Technique under Two Different Conditions for Measuring Oropharyngeal Swallowing Pressure, Tongue Strength and Endurance in Healthy Young Adults. | 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 Research Article Comparison of IOPI Use Technique under Two Different Conditions for Measuring Oropharyngeal Swallowing Pressure, Tongue Strength and Endurance in Healthy Young Adults. Zehra Yılmaz Eksen, Ayşegül Yılmaz, Eda Uzuner, Seyhun Topbaş This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7053677/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose To compare posterior tongue strength, endurance, and anterior / posterior swallowing pressures via the IOPI under marked and unmarked conditions and to examine correlations between intraoral tube length and pressure/duration in the unmarked condition. Methods A crossover design was used with 34 healthy adults (aged 20–39 years). Each parameter was measured three times under both conditions. Normality was tested via the Shapiro‒Wilk test. Pearson or Spearman correlations were used depending on the distribution. Paired t tests, Wilcoxon tests, and correlation analyses were conducted (R v4.1.2). Reliability was assessed in a subsample. Results No significant differences were found between the marked and unmarked means (all ps > 0.07), although the posterior swallowing pressure SD approached significance (t(33) = 1.537 p = 0.067). Strong positive correlations were observed between conditions (all r/ps > 0.727, ps 0.63, ps 0.706, ps < 0.005) were high, except for endurance (r = 0.232, p = 0.425). Conclusion Marking did not significantly affect outcomes, but tube length may influence posterior swallowing pressure. The protocol showed high reliability. Audiology & Speech-Language Pathology Head & Neck Surgery IOPI tongue strength tongue endurance swallowing pressure measurement reliability Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Introduction The strength and endurance of the tongue and lip muscles, along with oropharyngeal swallowing pressures, are critical components of nutrition, speech, and safe swallowing. Disorders affecting these parameters can occur at any age and require objective evaluation. The Iowa Oral Performance Instrument (IOPI), which is widely used in these evaluations [ 1 – 5 ], is considered a reliable tool in both evaluation and intervention processes regarding tongue strength measurement (6–9]. However, limited evidence exists regarding the reliability of endurance measures (6]. While endurance has been moderately effective in distinguishing between healthy individuals and clinical populations [ 4 ], studies involving older adults, healthy adults, and children have reported lower test–retest reliability for endurance measures [ 6 , 7 , 10 ]. Age-related changes in muscle mass and motor control have been suggested as possible contributors to reduced reliability in older adults [ 10 ], whereas improved oral motor control with age may explain the increased reliability among older children [ 6 ]. Children, elderly individuals and patients may have difficulty keeping the tongue bulb of the IOPI in place after it is placed in the mouth. A study conducted with pediatric participants reported that the bulb in their mouths slipped during endurance trials in some participants [ 6 ]. In those studies that used the IOPI, repetitive and comparative measurements were taken, and statistical analyses were performed. It is important to place the IOPI bulb at the same point each time during the measurement to obtain reliable results. However, there is no standard marking for length measurement on the inside of the mouth of the tube connecting the disposable bulb to the IOPI. This may make it difficult to ensure that the bulb and tube are positioned in the same position in the mouth for each measurement and may affect the consistency of the measurements. In studies conducted in this field, it was predicted that reliable results would be obtained in repeated measurements by marking the point of contact of the connecting tube with the lip, and measurements were taken with marking [ 2 , 3 , 9 , 11 – 15 ]. However, measurements taken under two different conditions with and without marking were not compared. Our study aims to investigate whether there is a difference between four parameters (posterior tongue strength, posterior tongue endurance, anterior and posterior tongue swallowing pressure) obtained as a result of measurements with and without marking the connecting tube of the IOPI device in healthy young individuals. In addition, this study aimed to examine the associations between the intraoral length of the tube and bulb and the outcome measures obtained under unmarked conditions. The findings of this study may contribute to the development of standardized protocol recommendations for the use of IOPIs in clinical assessment processes. Accordingly, the following hypotheses were tested in the study: H1: There will be a difference between the means of the overall scores obtained for each parameter of the measurements made in the marked and unmarked conditions. H2: The measurement result in the unmarked condition will show more variability than the measurement result (standard deviations) in the marked condition. H3: There would be a correlation between the pressure and duration measurements for each parameter in the unmarked condition and the tube lengths taken during these measurements. Method Research design and ethical approval A crossover design was used in this study. Approval for the study was obtained from the [XX] University Non-Interventional Clinical Research Local Ethics Committee on 04.07.2024 with decision number 656. After ethical approval, data were collected between July and September 2024 at [XX] University, [XX] Center. Participants The number of participants was determined via power analysis via the G*Power program [ 16 , 17 ]. The power analysis was based on the two-tailed paired samples t test, which is the statistical analysis planned within the scope of Hypothesis 1. As a result of this analysis, it was determined that at least 34 participants were needed at the 80% power level to reach a medium effect size (Cohen's d = 0.5). Accordingly, 46 healthy individuals between the ages of 20 and 39 were interviewed; however, since 12 participants did not meet the inclusion criteria, 34 participants (21 women, 13 men) were included in the study. Participation in the study was voluntary, and a snowball sampling method was used to recruit participants. All participants were asked to sign an informed consent form before starting the study. Inclusion criteria Healthy individuals aged 20–39 years were included in the study. The participants were required to have a history of falling from height; traffic accidents; head trauma; cleft lip and palate, head and neck anomaly or surgery; neurological or psychiatric disorders; regular medication use; feeding, swallowing, and motor speech disorders; and no condition affecting the use of the jaw muscles or temporomandibular joint. The health status of the participants was evaluated via the Demographic Characteristics Information Form; the strength, symmetry and range of motion (range) of tongue, lip, jaw and soft palate movements, as well as breathing and posture, were evaluated by the researcher via the Oral Peripheral Assessment Form. The Turkish Eating Assessment Tool (T-EAT-10) was administered to the participants in whom no problem was found in the oral peripheral evaluation to screen for possible swallowing disorders, and individuals with a score below 3 points were included in the study [ 18 ]. Exclusion criteria After completing the Demographic Characteristics Information Form and Oral Peripheral Assessment Form, participants who did not meet the inclusion criteria were excluded from the study. Participants who scored 3 points or more on the T-EAT 10 scale were excluded from the study because of the risk of possible swallowing problems [ 18 ]. In addition, individuals with difficulties speaking and understanding Turkish and speech and language therapists or students receiving education in this field were not included in the study. Instruments used in the study IOPI Model 3.1 was used to measure tongue strength, endurance and oropharyngeal swallowing pressures. The IOPI is a measuring device that measures the pressure applied to a disposable air-filled bulb in kPa and displays it numerically on the device screen. The device also has an LED light indicator section used for endurance measurements. The disposable part, which is connected to the IOPI device through a tube, consists of the bulb and the tube placed in the mouth. This disposable part was changed for each participant in our study to ensure hygiene conditions and to minimize measurement errors [ 9 ]. Surgical gloves, abeslang used during oral motor assessment, pre prepared medical tape, a 20 cm plastic ruler and forms to record the measurement results were also used in the measurements (see Fig. 1 at the end of the manuscript). Procedure and instructions Before starting the study, two experienced speech-language pathologists (20 + years and 5 + years) were given one-hour training by the researcher about the measurements to be performed with IOPI, the instructions to be applied and the experimental procedure. The measurement instructions to be used in the study were prepared by examining studies on tongue strength, endurance and oropharyngeal swallowing pressure measurements in the literature and the IOPI user manual [ 1 , 3 , 9 , 19 – 22 ]. The evaluation phase started with the participants signing the informed voluntary consent form. The researcher and the first rater then interviewed each participant one-on-one and completed the Demographic Characteristics Information Form and the Oral Peripheral Assessment Form. The participants also completed the Turkish Eating Assessment Tool (T-EAT-10) form, and IOPI measurements were started with individuals who met the inclusion criteria. For the IOPI measurements, posterior tongue strength (maximum tongue elevation pressure) and anterior and posterior tongue swallowing pressures (during effortful saliva swallowing) were recorded in kilopascals (kPa); posterior tongue strength was recorded in seconds (sec) [ 1 , 9 ]; and tube length was recorded in centimeters (cm). The first rater measured posterior tongue strength, posterior tongue endurance, and anterior and posterior tongue swallowing pressure parameters in all participants in the marked and unmarked conditions. In addition, to assess rater reliability, 20% of the participants, selected by lottery, were remeasured 15 days after the first measurement. For interrater reliability, 20% of the randomly selected participants were given a 3-hour rest break after the first rater's measurements, after which the second rater measured the same parameters. In a study conducted with healthy children, measurements were taken in the morning and afternoon in a similar manner to account for daily variability [ 19 ]. The rest periods were 30 seconds between each measurement, 2 minutes between each parameter and 5 minutes between the marked and unmarked conditions. To minimize potential order effects, a fixed alternating sequence was employed for the measurement conditions. Specifically, the first participant was measured first in the unmarked condition and then in the marked condition, whereas the second participant was measured first in the marked condition and then in the unmarked condition. This alternating order was applied systematically to all participants. The second rater also followed the same alternating sequence during reliability measurements. Unmarked posterior tongue strength measurement After preparing the tools and materials, the first rater showed the participant the position of the bulb in the mouth as described in the IOPI user manual. For the posterior tongue strength measurement, the tip of the IOPI bulb was aligned with the participant's hard and soft palate transition zone. The blue bulb was positioned at the midline of the tongue, approximately at the level of the first molar, as indicated in the manual. At this time, the participant was asked to compress the bulb by lifting the tongue as if making a /k/ sound. During the measurement, it was explained by showing correct and incorrect head postures that the tube of the bulb should be held gently between the incisors without pressing and biting and should be held with the lips without squeezing [ 1 ], and that the head should be in a neutral posture [ 23 ] and should not be supported by the chin. Measurements were taken after ensuring that the patient corrected his/her posture. Care was taken to ensure that the mandible was stable, the mouth was closed during the procedure, and the tube of the bulb was held by the rater to prevent it from slipping in front of the lips. The fact that some subjects received support from the mandible during the measurement and some did not and that the postures of some subjects were different might have affected the measurement results. Therefore, care was taken to take measurements by following the rules related to posture in all the parameters. In the unmarked posterior tongue strength measurement, the instruction “Press the tongue bulb as hard as you can with your tongue for about two seconds” was given, 3 measurements were made, and the measurement values were recorded [ 1 , 24 ]. Immediately after each measurement, the distance from the front of the lips (where the tape would be adhered in the marked measurement) to the extreme point of the bulb in the mouth was measured and recorded on the form. Unmarked posterior tongue endurance measurement For the posterior tongue strength measurement, the target value was set to 50% of the maximum posterior tongue strength (Pmax) by pressing the target mode button of the IOPI device via arrows [ 1 ]. The bulb was placed in the same position in the participant's mouth as described for the posterior tongue strength measurement. The participants were instructed, “Squeeze the tongue bulb until the top green light comes on and keep the light on as long as possible” [ 1 ]. When the top green light came on, the measurement started with a stopwatch, and the LED light sequence on the right side of the device was followed during the measurement. If the pressure dropped by 1 light, the participant was encouraged to press the bulb harder to return to the green light, and if he/she could not return to the target value within 2 seconds, the trial was terminated, and the endurance duration was recorded on the form in seconds [ 1 ]. During the duration measurement, participants were encouraged to press the bulb more strongly to make the green light come on again[ 24 ]. Three measurements were taken from each participant, and the durations were recorded. After each measurement, without changing the position of the bulb in the mouth, the length of the tube—from the front of the lips (the area to be taped in the marked measurement) to the end point of the bulb in the mouth—was measured and recorded on the form. Unmarked posterior tongue swallowing pressure measurement After the IOPI device was turned on, it was set to "peak" mode, and the measurement was performed using the same bulb placement as described in the posterior tongue strength assessment. The bulb was positioned according to the method applied in the studies by Van den Steen et al. [ 3 ], and an effortful swallowing instruction was preferred during the measurements. During both posterior and anterior tongue swallowing pressure assessments, participants were encouraged to press as firmly as possible, compress the bulb, and perform an effortful swallow. The participants were instructed, "While the tongue bulb is in your mouth, swallow your saliva forcefully." Three measurements were taken from each participant. Following each measurement, the peak pressure value recorded during swallowing and the intraoral length of the bulb portion were measured and documented on the form. Unmarked anterior tongue swallowing pressure measurement Following the posterior tongue swallowing pressure measurements, the IOPI bulb was placed on the participant’s hard palate, just behind the alveolar ridge. Care was taken to ensure that the bulb seal was positioned behind the incisors and that the bulb itself was aligned along the midline on the dorsal surface of the tongue. After the instructions were given, “While the tongue bulb is in your mouth, swallow your saliva forcefully,” the measurement was recorded. The intraoral tube length from the tip of the bulb to the front of the lips was subsequently measured and noted. Three measurements were taken for this parameter as well. Marked posterior tongue strength measurement For the marked posterior tongue strength measurement, the disposable bulb was positioned in the same intraoral location as in the previous posterior tongue measurements. A piece of tape, visible at the front of the lips (Figs. 1 – 2 ), was attached to the tube, and the posterior tongue strength was measured again, with the recorded pressure value noted. Following the measurement, the length from the taped section near the lips to the tip of the bulb was measured in centimeters and documented. Although some studies using the IOPI device have applied a marker, they have not measured the intraoral length from the marker to the bulb tip [ 2 , 3 , 9 ]. The results of the subsequent two measurements after the first trial were recorded; however, the intraoral length was not remeasured, as the tube had been fixed with tape and remained unchanged. The same intraoral length from the first measurement was documented in centimeters. During all the measurements, particular attention was given to maintaining the taped section in the same position and manually stabilizing the tube to prevent any displacement (Figs. 2 , 3 ). Marked posterior tongue endurance measurement During the marked posterior tongue endurance measurements, without removing the tape, the bulb and tube were positioned in the same placement as described for the unmarked posterior tongue endurance measurements. The same instructions were given, and three measurements were recorded. The measured endurance duration and the intraoral length previously recorded during the marked posterior tongue strength measurement were documented on the data form. Marked posterior tongue swallowing pressure measurement Without removing the tape, the bulb and tube were placed in the same place in the posterior tongue swallowing pressure measurement in the unlabeled measurement, and the same instructions were given. For both the marked posterior and anterior swallowing pressure measurements, the participants were instructed to perform effortful swallows. Each measurement was repeated three times and recorded accordingly. Marked anterior tongue swallowing pressure measurement For the marked anterior tongue swallowing pressure measurement, the tape on the tube was removed, and the tube was cleaned with an alcohol swab. The bulb was then positioned in the same manner as the unmarked anterior tongue swallowing pressure measurement. The tape was reapplied to the front of the lips, and the same instructions were provided to the participants. Both the pressure value and the length from the tape to the tip of the bulb were measured and recorded. Two additional measurements were taken in this manner. After performing the measurements in this order for the first participant, the order was reversed for the second participant, alternating between marked and unmarked measurements. The same duration and instructions were used for these measurements. For subsequent participants, the order was again alternated. In the marked measurements, careful attention was given to the placement of the tape and ensuring that the tube did not slide from this position. The rater held the tube to ensure proper bulb placement during measurement. The length between the tape placed near the lips and the tip of the bulb was measured and recorded (see Figs. 2 , 3 ). Reliability After measuring posterior tongue strength, endurance, and oropharyngeal swallowing pressure, the tape was removed, and the tube was cleaned thoroughly without leaving any residue. After all the measurements were completed by the first rater, a three-hour break was taken, and the measurements were conducted by the second rater in the afternoon. The measurements of 20% of the participants, previously selected by a random draw to be evaluated by the second rater, were conducted via the same instructions applied by the first rater. The second-rater also provided the same rest periods between each measurement, and each measurement was taken three times. The disposable part of the IOPI device, which is used for individual measurements and connects the bulb to the IOPI device (the tube entering the mouth), is shown in Fig. 2 (located at the end of the manuscript). The second rater followed the same procedure during their measurements. For the reliability of the first rater's measurements, 20% of the participants were remeasured 15 days later. These measurements were compared between the first rater's two sets of measurements, the measurements of the first and second raters, and the marked and unmarked measurements. As in previous studies, the average of the three measurements for each parameter was taken in our study [ 25 , 26 ]. Statistical Analyses As explained above, measurements were obtained on the basis of four parameters in both the marked and unmarked conditions. These parameters are posterior tongue strength in kPa, posterior tongue endurance in seconds, posterior tongue swallow in kPa, and anterior tongue swallow in kPa. For each of these parameters, three measurements were taken from each participant. The statistical analyses were conducted on the basis of the mean and standard deviation of these three measurements obtained for each parameter. The means showed the central tendency of the three measurements, hence providing an overall score for the relevant parameter, whereas the standard deviations reflected the dispersion among the three measurements, hence providing an assessment of the variability associated with the relevant parameter. Before each inferential test, the Shapiro–Wilk test was conducted to determine whether the data distribution was significantly different from the normal distribution. Five sets of statistical analyses were conducted. In the first set of analyses, the marked and unmarked conditions were compared in terms of the mean and standard deviation of the three measurements for each parameter. This was accomplished by using paired-samples t tests for normally distributed data and Wilcoxon signed-rank tests for nonnormally distributed data. The first set of analyses was intended to reveal whether the two conditions (marked and unmarked) differed in the overall scores obtained for each parameter (comparison of means) and whether the variability in measurements within each parameter differed between the conditions (comparison of standard deviations). Notably, for the comparison of standard deviations between the marked and unmarked comparisons, we used one-tailed comparisons, given that our expectation was for the unmarked condition to exhibit greater variability (standard deviations) than the marked condition. For all other statistical tests reported here, we used two-tailed tests. In the second set of analyses, the correlations between the marked and unmarked conditions in terms of the means of the three measurements for each parameter were examined by using the Pearson correlation coefficient for normally distributed data and Spearman's rank correlation coefficient for nonnormally distributed data. This second set of analyses was intended to reveal and quantify consistency between the two conditions (marked and unmarked) in terms of the overall scores for each parameter. The third set of analyses examined the correlations between the raw measurements and the lengths of the tube for each parameter, using the Pearson correlation coefficient for normally distributed data and Spearman's rank correlation coefficient for nonnormally distributed data. This third set of analyses was intended to examine whether the pressure and duration of each parameter correlated with the length of the tube. Thus, they were conducted only within the unmarked condition by including all three pressure/duration and length measurements within each parameter, given that the measurement of the tube length was repeated only within the unmarked condition. The remaining two sets of analyses were intended to measure the reliability of the measurements. That is, in the fourth set of analyses, the correlations between the means of the measurements in the test phase and those of the measurements in the retest phase (for the same participants) were computed. This fourth set of analyses was intended to assess test‒retest reliability and show whether the same participants’ scores were correlated at different times of measurement. Finally, the fifth set of analyses examined the correlations between the means of the measurements taken by the first rater and those of the measurements taken by the second rater (for the same participants). This fifth set of analyses was intended to assess interrater reliability and show whether the same participants’ scores were correlated even when measured by different raters. The reliability analyses utilized the Pearson correlation coefficient for normally distributed data and Spearman's rank correlation coefficient for nonnormally distributed data. Both reliability analyses were based on the data from seven randomly selected participants, with two values for each parameter (one from the marked condition and the other from the unmarked condition) per participant. All the statistical analyses were conducted in R version 4.1.2 (R Core Team, 2013). The statistical analysis code, along with the data used for the analyses, are shared in the online data repository: https://osf.io/8qw96/?view_only=1dee08d59198435899adf1622b9ed6c1 Results The mean, standard deviation, median and range values for the four parameters (for both the means and standard deviations of the three measurements within each parameter) are given in Table 1 at the end of the manuscript. The results of the five sets of analyses conducted are presented in the following subsections. Table 1 Descriptive statistics, paired comparisons and correlation analyses for the parameter means and standard deviations between the marked and unmarked conditions. Marked Unmarked Paired Comparison Correlation M SD Mdn Range M SD Mdn Range Posterior strength kPa M 37.63 11.67 39.00 16.3–58.3 38.86 12.31 39.50 12.7–60.0 t = 0.986, p = 0.331 r = 0.816 , p < 0.001 Posterior endurance sec M 15.02 14.44 9.60 2.3–65.3 14.82 18.19 8.35 2.7–84.0 V = 238, p = 0.453 ρ = 0.755 , p < 0.001 Posterior swallow kPa M 31.79 12.67 30.00 9.3–59.3 32.18 11.77 34.70 9.3–59.7 t = 0.256, p = 0.800 r = 0.728 , p < 0.001 Anterior swallow kPa M 35.25 12.41 32.50 17.3–59.3 35.57 12.02 35.00 7.3–59.7 t = 0.269, p = 0.790 r = 0.845 , p < 0.001 Posterior strength kPa SD 2.98 2.26 2.30 0.5–11.1 3.20 2.06 2.60 0.5–11.0 t = 0.555, p = 0.291 — Posterior endurance sec SD 2.75 2.29 1.60 0.0-8.6 4.68 10.77 2.35 0.0-63.8 V = 268, p = 0.592 — Posterior swallow kPa SD 3.04 1.77 2.75 0.5–7.3 3.96 2.88 3.20 0.5–10.6 t = 1.537, p = 0.067 — Anterior swallow kPa SD 3.30 1.89 3.00 0.5–6.5 3.79 2.57 3.55 0.0-9.9 t = 1.012, p = 0.159 — Comparison of marked and unmarked means and SDs The first set of analyses compared the marked and unmarked conditions in terms of the mean and standard deviation of the three measurements for each parameter via paired-samples t tests and Wilcoxon signed-rank tests. The comparisons of the marked and unmarked conditions for each parameter are illustrated via boxplots in Fig. 4 (see and of the manuscript) with respect to the mean of the measurements and in Fig. 5 (see and of the manuscript) with respect to the standard deviation of the measurements. The results of the statistical comparisons are presented in Table 1 above under the column titled “Paired Comparison”. As shown in the table, none of the comparisons yielded a statistically significant result. For the posterior swallow kPa SD, however, the difference between the marked and unmarked conditions approached statistical significance, t(33) = 1.537, p = 0.067. This occurred because the standard deviations of the three measurements of the posterior swallow kPa parameter in the unmarked condition (M = 3.96, SD = 2.88) were marginally greater than those in the marked condition (M = 3.04, SD = 1.77). Thus, the first set of analyses did not reveal a significant difference between the two conditions in terms of the overall scores obtained for each parameter (comparison of means) or in terms of the variability in measurements within each parameter (comparison of standard deviations). Correlations between the marked and unmarked means The second set of analyses examined the correlations between the marked and unmarked conditions in terms of the means of the three measurements for each parameter via the Pearson correlation coefficient and Spearman's rank correlation coefficient. The results of these correlation analyses are given in Table 1 at the end of the manuscript (column titled “Correlation”). As shown in Table 1 at the end of the manuscript, the marked and unmarked means exhibited a significant, large and positive correlation for each parameter, all r/ρs(32) > 0.727, all ps < 0.001. In parallel with the first set of analyses, the second set of analyses indicated that the two conditions (marked and unmarked) yielded similar and positively correlated scores. Correlations between tube length and pressure/duration within the unmarked condition The third set of analyses examined the correlations between the raw pressure/duration measurements and the lengths of the tube for each parameter only within the unmarked condition, where the tube length is measured separately for each of the three measurements within each parameter. These analyses revealed that tube length was significantly correlated with only the posterior swallow kPa, r(100) = -0.275, p = 0.005. This negative correlation indicates that longer tube lengths were associated with smaller pressure values for the posterior swallow parameter, as illustrated in Fig. 6 (see and of the manuscript). None of the other parameters (posterior strength in kPa, posterior endurance in seconds, anterior swallow in kPa) significantly correlated with tube length, all r/ρs(100) 0.325. Reliability Analyses The final analyses, the fourth and fifth sets of analyses, were intended to assess test-retest reliability and interrater reliability, respectively. Both reliability results are summarized in Table 2 (located at the end of the manuscript). The test-retest reliability analyses revealed that all the parameters exhibited significant, large and positive correlations between the two testing times, all of which were rs(12) > 0.630, all ps < 0.015. Finally, the interrater reliability analyses revealed that the two raters’ scores were significantly correlated with posterior strength kPa, posterior swallow kPa, and anterior swallow kPa, with large effect sizes (all rs(12) > 0.706, all ps < 0.005). However, the two raters’ scores did not significantly correlate with the posterior endurance parameter in seconds, r(12) = 0.232, p = 0.425. Overall, these results suggest that the procedures adopted in the current study had high test‒retest reliability for all the parameters and high interrater reliability for most of the parameters tested. Table 2 Test-retest and interrater reliability results. Test-retest reliability Interrater reliability Posterior strength kPa M r = 0.631 , p = 0.015 r = 0.707 , p = 0.005 Posterior endurance sec M r = 0.933 , p < 0.001 r = 0.232, p = 0.425 Posterior swallow kPa M r = 0.862 , p < 0.001 r = 0.737 , p = 0.003 Anterior swallow kPa M r = 0.869 , p < 0.001 r = 0.906 , p < 0.001 Discussion The aim of this study was to evaluate the impact of marking the intraoral position of the IOPI bulb on the reliability and variability of tongue strength, endurance, and oropharyngeal swallow pressure measurements in healthy young adults. The results provide robust information regarding the reliability of IOPI assessments under different conditions. In Hypothesis 1, no significant difference was found between the mean scores of each parameter in the marked and unmarked conditions. When this result was considered alongside test‒retest analyses by the first rater and the findings from the two raters, it supported the reliability of the commonly used measurement technique in the literature. This finding is consistent with a previous study by Adams et al., which demonstrated high reliability of tongue strength measurements via the IOPI device in healthy adults when standardized instructions were followed, even in the absence of physical markings on the bulb. The same study reported that the reliability of tongue endurance measurements was generally unsatisfactory and highlighted the need for further research [ 7 ]. Similarly, in our study, the results of the endurance measurements taken by the two raters were not significantly correlated, whereas significant and strong correlations were observed for other parameters related to tongue strength and swallowing. Vanderwegen et al. emphasized that anatomical landmarks and visual feedback can guide consistent bulb placement, particularly in anterior positions, and reduce dependence on physical cues [ 9 ]. According to Hypothesis 2, it was anticipated that the standard deviations (SDs) of the measurements in the unmarked condition would show greater variability than those in the marked condition would. Although no statistically significant difference was found, the difference in SD for posterior tongue measurements approached statistical significance between the marked and unmarked conditions. This occurred because the standard deviations of the three measurements of the posterior tongue in the unmarked condition were slightly larger than those in the marked condition (see Table 1 at the end of the manuscript). This finding aligns with our second hypothesis and reflects previous concerns raised by Palmer et al.; they noted that inconsistent bulb positioning in the posterior oral cavity, owing to anatomical complexity (i.e., variations in both neural input and peripheral muscle structures), might lead to less reproducible results (Kays et al.) [ 2 , 11 ]. Our data indicate that unmarked conditions may result in greater variability, particularly in tasks involving the posterior tongue. Given the narrower and more variable surface contact area in the oropharynx, slight deviations in bulb positioning can affect pressure values. This finding emphasizes the clinical importance of ensuring reproducible placement through anatomical guidance, consistent instructions, or physical markers, especially when monitoring a patient’s progress over time. In the analyses conducted under Hypothesis 3, the relationships between pressure and duration measurements obtained in the unmarked condition and tube length were evaluated. In this context, a significant negative correlation was found only for posterior tongue pressure with tube length. As shown in Fig. 6 (see and of the manuscript), the relationship between increased tube length and decreased pressure values is consistent with the near-significant values observed in Table 1 (located at the end of the manuscript). This finding points to the need for further investigation into the relationship between oropharyngeal swallowing pressure measurements and tube length with larger sample sizes. In previous studies in the literature, the length of the portion of the tube remaining in the mouth was not measured; only pressure values under marked conditions were recorded [ 2 , 9 , 11 – 15 , 19 ]. Therefore, systematically measuring the length of the IOPI device’s disposable part when positioned at different locations is essential for future research. Additionally, investigating the effects of different bulb placements on measurements during both effortful and spontaneous swallowing is recommended. In anterior tongue swallowing pressure measurements, the ease of bulb placement enhances the feasibility of these measurements; however, similar ease is not achievable for measurements in the posterior tongue region. In this context, the inclusion of tube length as a measurement parameter could increase measurement accuracy. This study was based on swallowing guidelines and bulb placement instructions that are widely accepted for validity in the literature, and tube lengths were also measured and included in the analyses. In the test‒retest analyses conducted to assess the reliability of measurement errors due to placement, both raters obtained similar results, indicating that the measurement differences were not due to rater error. In our study, after providing instructions for oropharyngeal swallowing measurements, participants were expected to perform the task with maximum effort. These instructions were given to prevent swallowing at lower pressure levels [ 3 ] and to achieve the maximum possible swallowing pressure. If the “swallow strongly” instruction had not been provided, some participants would have naturally swallowed forcefully, whereas others would not have exerted any effort. Thus, by emphasizing strong swallowing in our study, weak swallowing was excluded. For the measurements conducted via the IOPI, the instructions were followed in accordance with the literature, and the results obtained support the reliability of these measurement procedures. Test‒retest reliability analyses revealed high and statistically significant positive correlations across all the parameters. In the interrater reliability analyses, high levels of agreement were found between the raters' measurements for the posterior tongue strength, posterior, and anterior tongue swallowing pressure parameters. However, the interrater agreement for posterior tongue endurance measurements was not statistically significant. This finding aligns with previous studies that indicated low reliability in endurance measurements [ 7 ]. The literature includes studies in which endurance measurements were repeated once [ 9 ], twice [ 6 ], or three times. In this study, three measurements were taken for each parameter to evaluate the difference between the conditions with and without taping. The results obtained indicate that the current protocols are particularly strong in terms of test‒retest reliability and that interrater reliability is adequate for most parameters. Limitations The total duration of the study was limited to a single 45-minute session. During the first 15 minutes, the inclusion criteria for the participants were assessed, and the remaining time was used to perform measurements with the IOPI. In the selection of measured parameters, posterior tongue strength and endurance parameters were chosen because of the greater likelihood of tube misplacement or slippage during each measurement. In contrast, anterior tongue strength and endurance measurements were not utilized because tube placement could easily be achieved, and the limited time could lead to fatigue as measurements were prolonged. However, both posterior and anterior tongue swallowing pressures were measured for swallowing pressure assessments. As a result, no differences in length were observed for anterior placement, whereas a decrease in pressure was noted as length increased for posterior placement. These measurements are considered important in supporting the norms for oropharyngeal swallowing pressure and clinical decision-making processes during oropharyngeal swallowing therapies. Therefore, further studies with larger sample sizes, particularly those involving posterior tongue measurements with length measurements, are needed to provide more robust findings. Since it was not part of the scope of our study, the sex differences between the marked and unmarked measurements were not examined. However, this variable may be explored in future studies. Additionally, in this study, a comparison between the length of the disposable part inside the mouth in the unmarked condition and the lengths in the marked condition was not conducted. Future research should systematically evaluate the differences between these two conditions. While some studies involving marked measurements exist, these studies did not compare them with unmarked measurements or consider tube length. As a result, studies conducted on participant groups with similar characteristics, where both conditions are evaluated together, are needed. In this study, data obtained from 34 healthy individuals under both marked and unmarked conditions were evaluated. Future research, including larger samples with different age and sex groups, is expected to provide more generalizable findings, especially regarding oropharyngeal swallowing pressures. During the preparation of this work, the authors used DeepL and ChatGPT to improve language and readability. After using this tool/service, the authors reviewed and edited the content as needed and take full responsibility for the content of the publication. Declarations Acknowledgment This study was supported by XX under the XX No. XX. The funds that were taken were used solely for the purchase of the IOPI bulbs. Photographs and visuals: XX prepared the photos and graphics used in the research and gave permission for their use. Permission was obtained from XX for the use of facial photos in our research. We thank them for their support of our project. References Iowa Oral Performance Instrument Model 3.2, IOPI PRO User Manual Available from: https://iopimedical.com/wp-content/uploads/2025/03/800-3101-09_EN-IOPI-Pro-User-Manual-English.pdf Palmer PM, Neel AT, Sprouls G, Morrison L (2010) Swallow characteristics in patients with oculopharyngeal muscular dystrophy. J Speech Lang Hear Res Dec 1(6):1567–1578 Van den Steen L, Van Gestel D, Vanderveken O, Vanderwegen J, Lazarus C, Daisne JF et al (2019) Evolution of self-perceived swallowing function, tongue strength and swallow-related quality of life during radiotherapy in head and neck cancer patients. Head Neck. Jul 1;41(7):2197–207. https://doi:10.1002/hed.25684 Solomon NP, Robin DA, Luschei ES (2000) Strength, Endurance, and Stability of the Tongue and Hand in Parkinson Disease. J Speech Lang Hear Res 43:256–267 Park HS, Oh DH, Yoon T, Park JS (2019) Effect of effortful swallowing training on tongue strength and oropharyngeal swallowing function in stroke patients with dysphagia: a double-blind, randomized controlled trial. Int J Lang Commun Disord. May 1;54(3):479–84 McKay R, Smart S, Cocks N (2020) Investigating Tongue Strength and Endurance in Children Aged 6 to 11 Years. Dysphagia. 35(5):762–72. Available from: https://doi.org/10.1007/s00455-019-10081-2 Adams V, Mathisen B, Baines S, Lazarus C, Callister R (2014) Reliability of measurements of tongue and hand strength and endurance using the iowa oral performance instrument with healthy adults. Dysphagia Feb; 29(1):83–95 Adams V, Mathisen B, Baines S, Lazarus C, Callister R (2013) A systematic review and meta-analysis of measurements of tongue and hand strength and endurance using the Iowa Oral Performance Instrument (IOPI). Dysphagia 28(3):350–369 Vanderwegen J, Guns C, Van Nuffelen G, Elen R, De Bodt M (2013) The influence of age, sex, bulb position, visual feedback, and the order of testing on maximum anterior and posterior tongue strength and endurance in healthy Belgian adults. Dysphagia 28(2):159–166 Adams V, Mathisen B, Baines S, Lazarus C, Callister R (2015) Reliability of measurements of tongue and hand strength and endurance using the Iowa Oral Performance Instrument with elderly adults. Disabil Rehabil. Mar 1;37(5):389–95 Kays SA, Hind JA, Gangnon RE, Robbins J Effects of Dining on Tongue Endurance and Swallowing-Related Outcomes. Journal of Speech, Language, and, Research H (2010) Aug;(53):898–907 Oh JC (2024) Effect of Visual Biofeedback Obtained Using the Iowa Oral Performance Instrument on the Suprahyoid Muscle Activation Level During Effortful Swallowing Maneuver. Dysphagia. Jun 1;39(3):433–43 Oh JC (2018) Effect of the head extension swallowing exercise on suprahyoid muscle activity in elderly individuals. Exp Gerontol Sep 1:110:133–138 Oh JC (2021) Systematic Effortful Swallowing Exercise Without External Resistance Does Not Increase Swallowing-Related Muscle Strength in the Elderly. Dysphagia. Jun 1;36(3):465–73 Oh JC (2025) Effect of Visual Biofeedback Using the Iowa Oral Performance Instrument and Auditory Feedback on Floor-of-the-Mouth Muscle Activation and Oral Pressure During Effortful Swallowing in Healthy Older Adults. Dysphagia. Apr 1; Available from: https://link.springer.com/ 10.1007/s00455-025-10824-4 Faul F, Erdfelder E, Lang A-G, Buchner A (2007) G*Power 3:A Flexible Statistical Power Analysis Program for the Social, Behavioral, and Biomedical Sciences. Behav Res Methods 39(2):175–191 Faul F, Erdfelder E, Buchner A, Lang A-G (2009) Statistical power analyses using G*Power 3.1: Tests for correlation and regression analyses. Behav Res Methods 41(4):1149–1160 Demir N, Serel Arslan S, İnal Ö, Karaduman AA (2016) Reliability and Validity of the Turkish Eating Assessment Tool (T-EAT-10). Dysphagia 31(5):644–649 Vanderwegen J, Van Nuffelen G, Elen R, De Bodt M (2019) The Influence of Age, Sex, Visual Feedback, Bulb Position, and the Order of Testing on Maximum Anterior and Posterior Tongue Strength in Healthy Belgian Children. Dysphagia. Dec 1;34(6):834–51 Youmans SR, Stierwalt JAG (2006) Measures of tongue function related to normal swallowing. Dysphagia Apr 21(2):102–111 Potter NL, Short R (2009) Maximal tongue strength in typically developing children and adolescents. Dysphagia 24(4):391–397 Potter NL, Bajwa A, Wilson EH, VanDam M (2021) Developmental Changes in Tongue Strength, Swallow Pressures, and Tongue Endurance. Dysphagia Oct 36(5):854–863. https://doi.org/10.1007/s00455-020-10200-4 Paris-Alemany A, Proy-Acosta A, Adraos-Juárez D, Suso-Martí L, La Touche R, Chamorro-Sánchez J (2021) Influence of the Craniocervical Posture on Tongue Strength and Endurance. Dysphagia. Apr 1;36(2):293–302 Pizzorni N, Ginocchio D, Bianchi F, Feroldi S, Vedrodyova M, Mora G et al (2020) Association between maximum tongue pressure and swallowing safety and efficacy in amyotrophic lateral sclerosis. Neurogastroenterology and Motility. Aug 1;32(8) Crow HC, Ship JA (1996) Tongue strength and endurance in different aged individuals. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences. 51(5):M247–250. 10.1093/gerona/51a.5.m247 Utanohara Y, Hayashi R, Yoshikawa M, Yoshida M, Tsuga K, Akagawa Y (2008) Standard values of maximum tongue pressure taken using newly developed disposable tongue pressure measurement device. Dysphagia Sep 23(3):286–290 Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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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-7053677","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":481092233,"identity":"3e5c173a-c71c-480a-9ea9-295be8c97797","order_by":0,"name":"Zehra Yılmaz Eksen","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAqUlEQVRIiWNgGAWjYFAC5gaGDwwMCaRoYWxgnEGyFmYekrTIz0hs3WzbZpfHz97A+OFjDjF2zEhsu53bllws2XOAWXLmNiK0MEuAtTAnbriRwMbMS4wWNpAWy7Z6ErTwgLQwth0mQYsEz8O2mz3njifO7DnYTJxf5NuTj934UVad2M/efPDDR2K0MAgkAIONDcRibCBGPRDwHwASf4hUPApGwSgYBSMTAADVeTkRXBWOyAAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0003-1358-9961","institution":"Department of Speech and Language Therapy, Graduate School of Health Sciences, Istanbul Medipol University","correspondingAuthor":true,"prefix":"","firstName":"Zehra","middleName":"Yılmaz","lastName":"Eksen","suffix":""},{"id":481092234,"identity":"9b937302-0387-40e5-8084-4a5dbd4ae490","order_by":1,"name":"Ayşegül Yılmaz","email":"","orcid":"https://orcid.org/0000-0002-0577-9864","institution":"Department of Speech and Language Therapy, Graduate School of Health Sciences, Istanbul Medipol University","correspondingAuthor":false,"prefix":"","firstName":"Ayşegül","middleName":"","lastName":"Yılmaz","suffix":""},{"id":481092351,"identity":"f7adc771-64b2-40df-be88-d2712c9054c6","order_by":2,"name":"Eda Uzuner","email":"","orcid":"https://orcid.org/0000-0002-5716-7018","institution":"Department of Speech and Language Therapy, Graduate School of Health Sciences, Istanbul Medipol University","correspondingAuthor":false,"prefix":"","firstName":"Eda","middleName":"","lastName":"Uzuner","suffix":""},{"id":481092628,"identity":"c5a606d4-f104-41a4-aa24-835b5df28c0e","order_by":3,"name":"Seyhun Topbaş","email":"","orcid":"https://orcid.org/0000-0003-2515-3874","institution":"Department of Speech and Language Therapy, Faculty of Health Sciences, Istanbul Medipol University","correspondingAuthor":false,"prefix":"","firstName":"Seyhun","middleName":"","lastName":"Topbaş","suffix":""}],"badges":[],"createdAt":"2025-07-05 14:36:29","currentVersionCode":1,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-7053677/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7053677/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":86217579,"identity":"72608937-b812-450c-bc87-3c72e5b1e87b","added_by":"auto","created_at":"2025-07-08 06:22:21","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":65107,"visible":true,"origin":"","legend":"\u003cp\u003eDisposable materials used in the measurements and recording form\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7053677/v1/c0591db62fb309ecfedf6fa1.jpg"},{"id":86218373,"identity":"12dfeb15-88e1-4e0c-bbaf-e99250b18241","added_by":"auto","created_at":"2025-07-08 06:30:21","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":30937,"visible":true,"origin":"","legend":"\u003cp\u003eBulb placement during marked posterior tongue measurements\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7053677/v1/74a02fe3e2fb315cea556d3a.jpg"},{"id":86217583,"identity":"274776c8-e144-4056-ba9a-a69b965d9303","added_by":"auto","created_at":"2025-07-08 06:22:21","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":28433,"visible":true,"origin":"","legend":"\u003cp\u003eExternal view of the position of the tube during the marked measurement\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7053677/v1/b7a6253d772d576d04f985f8.jpg"},{"id":86217582,"identity":"54b64a90-58ea-4dce-b0c4-c96526144d5a","added_by":"auto","created_at":"2025-07-08 06:22:21","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":28798,"visible":true,"origin":"","legend":"\u003cp\u003eBoxplots of the mean pressure and duration values for the marked and unmarked conditions.\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7053677/v1/18b703af04ba4a0fc5d9a04d.jpg"},{"id":86218611,"identity":"7770c2a1-7ce0-46fc-93de-5c3426be5c9a","added_by":"auto","created_at":"2025-07-08 06:38:21","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":29235,"visible":true,"origin":"","legend":"\u003cp\u003eBoxplots of standard deviations of pressure and duration values for marked and unmarked conditions.\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7053677/v1/87030bce0e83a128faf491cf.jpg"},{"id":86218375,"identity":"4bc3916f-0173-4ff4-8f45-3db1a918a02c","added_by":"auto","created_at":"2025-07-08 06:30:21","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":29906,"visible":true,"origin":"","legend":"\u003cp\u003eScatterplot with a linear regression line illustrating the significant correlation between tube length and pressure for the posterior swallow parameter within the unmarked condition. The shaded area represents the 95% confidence interval.\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7053677/v1/ec2821b629bd3730ef3e2f0a.jpg"},{"id":86219495,"identity":"289f7d7f-24e2-4e47-ae1e-7331604ba887","added_by":"auto","created_at":"2025-07-08 06:46:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1186818,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7053677/v1/cfa811c1-9e63-4192-8e05-f7ade7879d9d.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eComparison of IOPI Use Technique under Two Different Conditions for Measuring Oropharyngeal Swallowing Pressure, Tongue Strength and Endurance in Healthy Young Adults.\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe strength and endurance of the tongue and lip muscles, along with oropharyngeal swallowing pressures, are critical components of nutrition, speech, and safe swallowing. Disorders affecting these parameters can occur at any age and require objective evaluation. The Iowa Oral Performance Instrument (IOPI), which is widely used in these evaluations [\u003cspan additionalcitationids=\"CR2 CR3 CR4\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], is considered a reliable tool in both evaluation and intervention processes regarding tongue strength measurement (6\u0026ndash;9]. However, limited evidence exists regarding the reliability of endurance measures (6]. While endurance has been moderately effective in distinguishing between healthy individuals and clinical populations [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], studies involving older adults, healthy adults, and children have reported lower test\u0026ndash;retest reliability for endurance measures [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Age-related changes in muscle mass and motor control have been suggested as possible contributors to reduced reliability in older adults [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], whereas improved oral motor control with age may explain the increased reliability among older children [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Children, elderly individuals and patients may have difficulty keeping the tongue bulb of the IOPI in place after it is placed in the mouth. A study conducted with pediatric participants reported that the bulb in their mouths slipped during endurance trials in some participants [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. In those studies that used the IOPI, repetitive and comparative measurements were taken, and statistical analyses were performed. It is important to place the IOPI bulb at the same point each time during the measurement to obtain reliable results. However, there is no standard marking for length measurement on the inside of the mouth of the tube connecting the disposable bulb to the IOPI. This may make it difficult to ensure that the bulb and tube are positioned in the same position in the mouth for each measurement and may affect the consistency of the measurements. In studies conducted in this field, it was predicted that reliable results would be obtained in repeated measurements by marking the point of contact of the connecting tube with the lip, and measurements were taken with marking [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan additionalcitationids=\"CR12 CR13 CR14\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. However, measurements taken under two different conditions with and without marking were not compared. Our study aims to investigate whether there is a difference between four parameters (posterior tongue strength, posterior tongue endurance, anterior and posterior tongue swallowing pressure) obtained as a result of measurements with and without marking the connecting tube of the IOPI device in healthy young individuals. In addition, this study aimed to examine the associations between the intraoral length of the tube and bulb and the outcome measures obtained under unmarked conditions. The findings of this study may contribute to the development of standardized protocol recommendations for the use of IOPIs in clinical assessment processes. Accordingly, the following hypotheses were tested in the study:\u003c/p\u003e\u003cp\u003eH1: There will be a difference between the means of the overall scores obtained for each parameter of the measurements made in the marked and unmarked conditions.\u003c/p\u003e\u003cp\u003eH2: The measurement result in the unmarked condition will show more variability than the measurement result (standard deviations) in the marked condition.\u003c/p\u003e\u003cp\u003eH3: There would be a correlation between the pressure and duration measurements for each parameter in the unmarked condition and the tube lengths taken during these measurements.\u003c/p\u003e"},{"header":"Method","content":"\u003cp\u003e\u003cb\u003eResearch design and ethical approval\u003c/b\u003e\u003c/p\u003e\u003cp\u003eA crossover design was used in this study. Approval for the study was obtained from the [XX] University Non-Interventional Clinical Research Local Ethics Committee on 04.07.2024 with decision number 656. After ethical approval, data were collected between July and September 2024 at [XX] University, [XX] Center.\u003c/p\u003e\u003cp\u003e\u003cb\u003eParticipants\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe number of participants was determined via power analysis via the G*Power program [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The power analysis was based on the two-tailed paired samples t test, which is the statistical analysis planned within the scope of Hypothesis 1. As a result of this analysis, it was determined that at least 34 participants were needed at the 80% power level to reach a medium effect size (Cohen's d\u0026thinsp;=\u0026thinsp;0.5). Accordingly, 46 healthy individuals between the ages of 20 and 39 were interviewed; however, since 12 participants did not meet the inclusion criteria, 34 participants (21 women, 13 men) were included in the study. Participation in the study was voluntary, and a snowball sampling method was used to recruit participants. All participants were asked to sign an informed consent form before starting the study.\u003c/p\u003e\u003cp\u003e\u003cb\u003eInclusion criteria\u003c/b\u003e\u003c/p\u003e\u003cp\u003eHealthy individuals aged 20\u0026ndash;39 years were included in the study. The participants were required to have a history of falling from height; traffic accidents; head trauma; cleft lip and palate, head and neck anomaly or surgery; neurological or psychiatric disorders; regular medication use; feeding, swallowing, and motor speech disorders; and no condition affecting the use of the jaw muscles or temporomandibular joint. The health status of the participants was evaluated via the Demographic Characteristics Information Form; the strength, symmetry and range of motion (range) of tongue, lip, jaw and soft palate movements, as well as breathing and posture, were evaluated by the researcher via the Oral Peripheral Assessment Form. The Turkish Eating Assessment Tool (T-EAT-10) was administered to the participants in whom no problem was found in the oral peripheral evaluation to screen for possible swallowing disorders, and individuals with a score below 3 points were included in the study [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003cb\u003eExclusion criteria\u003c/b\u003e\u003c/p\u003e\u003cp\u003eAfter completing the Demographic Characteristics Information Form and Oral Peripheral Assessment Form, participants who did not meet the inclusion criteria were excluded from the study. Participants who scored 3 points or more on the T-EAT 10 scale were excluded from the study because of the risk of possible swallowing problems [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. In addition, individuals with difficulties speaking and understanding Turkish and speech and language therapists or students receiving education in this field were not included in the study.\u003c/p\u003e\u003cp\u003e\u003cb\u003eInstruments used in the study\u003c/b\u003e\u003c/p\u003e\u003cp\u003eIOPI Model 3.1 was used to measure tongue strength, endurance and oropharyngeal swallowing pressures. The IOPI is a measuring device that measures the pressure applied to a disposable air-filled bulb in kPa and displays it numerically on the device screen. The device also has an LED light indicator section used for endurance measurements. The disposable part, which is connected to the IOPI device through a tube, consists of the bulb and the tube placed in the mouth. This disposable part was changed for each participant in our study to ensure hygiene conditions and to minimize measurement errors [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Surgical gloves, abeslang used during oral motor assessment, pre prepared medical tape, a 20 cm plastic ruler and forms to record the measurement results were also used in the measurements (see Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e at the end of the manuscript).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eProcedure and instructions\u003c/b\u003e\u003c/p\u003e\u003cp\u003eBefore starting the study, two experienced speech-language pathologists (20\u0026thinsp;+\u0026thinsp;years and 5\u0026thinsp;+\u0026thinsp;years) were given one-hour training by the researcher about the measurements to be performed with IOPI, the instructions to be applied and the experimental procedure. The measurement instructions to be used in the study were prepared by examining studies on tongue strength, endurance and oropharyngeal swallowing pressure measurements in the literature and the IOPI user manual [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan additionalcitationids=\"CR20 CR21\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The evaluation phase started with the participants signing the informed voluntary consent form. The researcher and the first rater then interviewed each participant one-on-one and completed the Demographic Characteristics Information Form and the Oral Peripheral Assessment Form. The participants also completed the Turkish Eating Assessment Tool (T-EAT-10) form, and IOPI measurements were started with individuals who met the inclusion criteria. For the IOPI measurements, posterior tongue strength (maximum tongue elevation pressure) and anterior and posterior tongue swallowing pressures (during effortful saliva swallowing) were recorded in kilopascals (kPa); posterior tongue strength was recorded in seconds (sec) [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]; and tube length was recorded in centimeters (cm). The first rater measured posterior tongue strength, posterior tongue endurance, and anterior and posterior tongue swallowing pressure parameters in all participants in the marked and unmarked conditions. In addition, to assess rater reliability, 20% of the participants, selected by lottery, were remeasured 15 days after the first measurement. For interrater reliability, 20% of the randomly selected participants were given a 3-hour rest break after the first rater's measurements, after which the second rater measured the same parameters. In a study conducted with healthy children, measurements were taken in the morning and afternoon in a similar manner to account for daily variability [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The rest periods were 30 seconds between each measurement, 2 minutes between each parameter and 5 minutes between the marked and unmarked conditions.\u003c/p\u003e\u003cp\u003eTo minimize potential order effects, a fixed alternating sequence was employed for the measurement conditions. Specifically, the first participant was measured first in the unmarked condition and then in the marked condition, whereas the second participant was measured first in the marked condition and then in the unmarked condition. This alternating order was applied systematically to all participants. The second rater also followed the same alternating sequence during reliability measurements.\u003c/p\u003e\u003cp\u003e\u003cb\u003eUnmarked posterior tongue strength measurement\u003c/b\u003e\u003c/p\u003e\u003cp\u003eAfter preparing the tools and materials, the first rater showed the participant the position of the bulb in the mouth as described in the IOPI user manual. For the posterior tongue strength measurement, the tip of the IOPI bulb was aligned with the participant's hard and soft palate transition zone. The blue bulb was positioned at the midline of the tongue, approximately at the level of the first molar, as indicated in the manual. At this time, the participant was asked to compress the bulb by lifting the tongue as if making a /k/ sound. During the measurement, it was explained by showing correct and incorrect head postures that the tube of the bulb should be held gently between the incisors without pressing and biting and should be held with the lips without squeezing [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], and that the head should be in a neutral posture [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] and should not be supported by the chin. Measurements were taken after ensuring that the patient corrected his/her posture. Care was taken to ensure that the mandible was stable, the mouth was closed during the procedure, and the tube of the bulb was held by the rater to prevent it from slipping in front of the lips. The fact that some subjects received support from the mandible during the measurement and some did not and that the postures of some subjects were different might have affected the measurement results. Therefore, care was taken to take measurements by following the rules related to posture in all the parameters. In the unmarked posterior tongue strength measurement, the instruction \u0026ldquo;Press the tongue bulb as hard as you can with your tongue for about two seconds\u0026rdquo; was given, 3 measurements were made, and the measurement values were recorded [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Immediately after each measurement, the distance from the front of the lips (where the tape would be adhered in the marked measurement) to the extreme point of the bulb in the mouth was measured and recorded on the form.\u003c/p\u003e\u003cp\u003e\u003cb\u003eUnmarked posterior tongue endurance measurement\u003c/b\u003e\u003c/p\u003e\u003cp\u003eFor the posterior tongue strength measurement, the target value was set to 50% of the maximum posterior tongue strength (Pmax) by pressing the target mode button of the IOPI device via arrows [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. The bulb was placed in the same position in the participant's mouth as described for the posterior tongue strength measurement. The participants were instructed, \u0026ldquo;Squeeze the tongue bulb until the top green light comes on and keep the light on as long as possible\u0026rdquo; [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. When the top green light came on, the measurement started with a stopwatch, and the LED light sequence on the right side of the device was followed during the measurement. If the pressure dropped by 1 light, the participant was encouraged to press the bulb harder to return to the green light, and if he/she could not return to the target value within 2 seconds, the trial was terminated, and the endurance duration was recorded on the form in seconds [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. During the duration measurement, participants were encouraged to press the bulb more strongly to make the green light come on again[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Three measurements were taken from each participant, and the durations were recorded. After each measurement, without changing the position of the bulb in the mouth, the length of the tube\u0026mdash;from the front of the lips (the area to be taped in the marked measurement) to the end point of the bulb in the mouth\u0026mdash;was measured and recorded on the form.\u003c/p\u003e\u003cp\u003e\u003cb\u003eUnmarked posterior tongue swallowing pressure measurement\u003c/b\u003e\u003c/p\u003e\u003cp\u003eAfter the IOPI device was turned on, it was set to \"peak\" mode, and the measurement was performed using the same bulb placement as described in the posterior tongue strength assessment. The bulb was positioned according to the method applied in the studies by Van den Steen et al. [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], and an effortful swallowing instruction was preferred during the measurements. During both posterior and anterior tongue swallowing pressure assessments, participants were encouraged to press as firmly as possible, compress the bulb, and perform an effortful swallow. The participants were instructed, \"While the tongue bulb is in your mouth, swallow your saliva forcefully.\" Three measurements were taken from each participant. Following each measurement, the peak pressure value recorded during swallowing and the intraoral length of the bulb portion were measured and documented on the form.\u003c/p\u003e\u003cp\u003e\u003cb\u003eUnmarked anterior tongue swallowing pressure measurement\u003c/b\u003e\u003c/p\u003e\u003cp\u003e Following the posterior tongue swallowing pressure measurements, the IOPI bulb was placed on the participant\u0026rsquo;s hard palate, just behind the alveolar ridge. Care was taken to ensure that the bulb seal was positioned behind the incisors and that the bulb itself was aligned along the midline on the dorsal surface of the tongue. After the instructions were given, \u0026ldquo;While the tongue bulb is in your mouth, swallow your saliva forcefully,\u0026rdquo; the measurement was recorded. The intraoral tube length from the tip of the bulb to the front of the lips was subsequently measured and noted. Three measurements were taken for this parameter as well.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMarked posterior tongue strength measurement\u003c/b\u003e\u003c/p\u003e\u003cp\u003eFor the marked posterior tongue strength measurement, the disposable bulb was positioned in the same intraoral location as in the previous posterior tongue measurements. A piece of tape, visible at the front of the lips (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), was attached to the tube, and the posterior tongue strength was measured again, with the recorded pressure value noted. Following the measurement, the length from the taped section near the lips to the tip of the bulb was measured in centimeters and documented. Although some studies using the IOPI device have applied a marker, they have not measured the intraoral length from the marker to the bulb tip [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The results of the subsequent two measurements after the first trial were recorded; however, the intraoral length was not remeasured, as the tube had been fixed with tape and remained unchanged. The same intraoral length from the first measurement was documented in centimeters. During all the measurements, particular attention was given to maintaining the taped section in the same position and manually stabilizing the tube to prevent any displacement (Figs.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eMarked posterior tongue endurance measurement\u003c/b\u003e\u003c/p\u003e\u003cp\u003eDuring the marked posterior tongue endurance measurements, without removing the tape, the bulb and tube were positioned in the same placement as described for the unmarked posterior tongue endurance measurements. The same instructions were given, and three measurements were recorded. The measured endurance duration and the intraoral length previously recorded during the marked posterior tongue strength measurement were documented on the data form.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMarked posterior tongue swallowing pressure measurement\u003c/b\u003e\u003c/p\u003e\u003cp\u003eWithout removing the tape, the bulb and tube were placed in the same place in the posterior tongue swallowing pressure measurement in the unlabeled measurement, and the same instructions were given. For both the marked posterior and anterior swallowing pressure measurements, the participants were instructed to perform effortful swallows. Each measurement was repeated three times and recorded accordingly.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMarked anterior tongue swallowing pressure measurement\u003c/b\u003e\u003c/p\u003e\u003cp\u003eFor the marked anterior tongue swallowing pressure measurement, the tape on the tube was removed, and the tube was cleaned with an alcohol swab. The bulb was then positioned in the same manner as the unmarked anterior tongue swallowing pressure measurement. The tape was reapplied to the front of the lips, and the same instructions were provided to the participants. Both the pressure value and the length from the tape to the tip of the bulb were measured and recorded. Two additional measurements were taken in this manner. After performing the measurements in this order for the first participant, the order was reversed for the second participant, alternating between marked and unmarked measurements. The same duration and instructions were used for these measurements. For subsequent participants, the order was again alternated. In the marked measurements, careful attention was given to the placement of the tape and ensuring that the tube did not slide from this position. The rater held the tube to ensure proper bulb placement during measurement. The length between the tape placed near the lips and the tip of the bulb was measured and recorded (see Figs.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cb\u003eReliability\u003c/b\u003e\u003c/p\u003e\u003cp\u003eAfter measuring posterior tongue strength, endurance, and oropharyngeal swallowing pressure, the tape was removed, and the tube was cleaned thoroughly without leaving any residue. After all the measurements were completed by the first rater, a three-hour break was taken, and the measurements were conducted by the second rater in the afternoon. The measurements of 20% of the participants, previously selected by a random draw to be evaluated by the second rater, were conducted via the same instructions applied by the first rater. The second-rater also provided the same rest periods between each measurement, and each measurement was taken three times. The disposable part of the IOPI device, which is used for individual measurements and connects the bulb to the IOPI device (the tube entering the mouth), is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e (located at the end of the manuscript). The second rater followed the same procedure during their measurements. For the reliability of the first rater's measurements, 20% of the participants were remeasured 15 days later. These measurements were compared between the first rater's two sets of measurements, the measurements of the first and second raters, and the marked and unmarked measurements. As in previous studies, the average of the three measurements for each parameter was taken in our study [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e\u003cp\u003e\u003cb\u003eStatistical Analyses\u003c/b\u003e\u003c/p\u003e\u003cp\u003eAs explained above, measurements were obtained on the basis of four parameters in both the marked and unmarked conditions. These parameters are posterior tongue strength in kPa, posterior tongue endurance in seconds, posterior tongue swallow in kPa, and anterior tongue swallow in kPa. For each of these parameters, three measurements were taken from each participant. The statistical analyses were conducted on the basis of the mean and standard deviation of these three measurements obtained for each parameter. The means showed the central tendency of the three measurements, hence providing an overall score for the relevant parameter, whereas the standard deviations reflected the dispersion among the three measurements, hence providing an assessment of the variability associated with the relevant parameter.\u003c/p\u003e\u003cp\u003eBefore each inferential test, the Shapiro\u0026ndash;Wilk test was conducted to determine whether the data distribution was significantly different from the normal distribution. Five sets of statistical analyses were conducted. In the first set of analyses, the marked and unmarked conditions were compared in terms of the mean and standard deviation of the three measurements for each parameter. This was accomplished by using paired-samples t tests for normally distributed data and Wilcoxon signed-rank tests for nonnormally distributed data. The first set of analyses was intended to reveal whether the two conditions (marked and unmarked) differed in the overall scores obtained for each parameter (comparison of means) and whether the variability in measurements within each parameter differed between the conditions (comparison of standard deviations). Notably, for the comparison of standard deviations between the marked and unmarked comparisons, we used one-tailed comparisons, given that our expectation was for the unmarked condition to exhibit greater variability (standard deviations) than the marked condition. For all other statistical tests reported here, we used two-tailed tests. In the second set of analyses, the correlations between the marked and unmarked conditions in terms of the means of the three measurements for each parameter were examined by using the Pearson correlation coefficient for normally distributed data and Spearman's rank correlation coefficient for nonnormally distributed data. This second set of analyses was intended to reveal and quantify consistency between the two conditions (marked and unmarked) in terms of the overall scores for each parameter. The third set of analyses examined the correlations between the raw measurements and the lengths of the tube for each parameter, using the Pearson correlation coefficient for normally distributed data and Spearman's rank correlation coefficient for nonnormally distributed data. This third set of analyses was intended to examine whether the pressure and duration of each parameter correlated with the length of the tube. Thus, they were conducted only within the unmarked condition by including all three pressure/duration and length measurements within each parameter, given that the measurement of the tube length was repeated only within the unmarked condition.\u003c/p\u003e\u003cp\u003eThe remaining two sets of analyses were intended to measure the reliability of the measurements. That is, in the fourth set of analyses, the correlations between the means of the measurements in the test phase and those of the measurements in the retest phase (for the same participants) were computed. This fourth set of analyses was intended to assess test‒retest reliability and show whether the same participants\u0026rsquo; scores were correlated at different times of measurement. Finally, the fifth set of analyses examined the correlations between the means of the measurements taken by the first rater and those of the measurements taken by the second rater (for the same participants). This fifth set of analyses was intended to assess interrater reliability and show whether the same participants\u0026rsquo; scores were correlated even when measured by different raters. The reliability analyses utilized the Pearson correlation coefficient for normally distributed data and Spearman's rank correlation coefficient for nonnormally distributed data. Both reliability analyses were based on the data from seven randomly selected participants, with two values for each parameter (one from the marked condition and the other from the unmarked condition) per participant.\u003c/p\u003e\u003cp\u003eAll the statistical analyses were conducted in R version 4.1.2 (R Core Team, 2013). The statistical analysis code, along with the data used for the analyses, are shared in the online data repository:\u003c/p\u003e\u003cp\u003e\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://osf.io/8qw96/?view_only=1dee08d59198435899adf1622b9ed6c1\u003c/span\u003e\u003cspan address=\"https://osf.io/8qw96/?view_only=1dee08d59198435899adf1622b9ed6c1\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe mean, standard deviation, median and range values for the four parameters (for both the means and standard deviations of the three measurements within each parameter) are given in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e at the end of the manuscript. The results of the five sets of analyses conducted are presented in the following subsections.\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\u003eDescriptive statistics, paired comparisons and correlation analyses for the parameter means and standard deviations between the marked and unmarked conditions.\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=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" 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\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" 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\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e\u003cp\u003eMarked\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"4\" nameend=\"c9\" namest=\"c6\"\u003e\u003cp\u003eUnmarked\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003ePaired Comparison\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c11\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eCorrelation\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSD\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMdn\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eRange\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eM\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eSD\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eMdn\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eRange\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePosterior strength kPa M\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e37.63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e11.67\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e39.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e16.3\u0026ndash;58.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e38.86\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e12.31\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e39.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e12.7\u0026ndash;60.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e\u003cem\u003et\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.986, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.331\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e\u003cb\u003er\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.816\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u0026thinsp;\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePosterior endurance sec M\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e15.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e14.44\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e9.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.3\u0026ndash;65.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e14.82\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e18.19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e8.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e2.7\u0026ndash;84.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e\u003cem\u003eV\u003c/em\u003e\u0026thinsp;=\u0026thinsp;238, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.453\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e\u003cb\u003eρ\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.755\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u0026thinsp;\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePosterior swallow kPa M\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e31.79\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e12.67\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e30.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e9.3\u0026ndash;59.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e32.18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e11.77\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e34.70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e9.3\u0026ndash;59.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e\u003cem\u003et\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.256, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.800\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e\u003cb\u003er\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.728\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u0026thinsp;\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAnterior swallow kPa M\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e35.25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e12.41\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e32.50\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e17.3\u0026ndash;59.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e35.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e12.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e35.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e7.3\u0026ndash;59.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e\u003cem\u003et\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.269, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.790\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e\u003cb\u003er\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.845\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u0026thinsp;\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePosterior strength kPa SD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2.98\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e2.30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.5\u0026ndash;11.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e2.06\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e2.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.5\u0026ndash;11.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e\u003cem\u003et\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.555, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.291\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePosterior endurance sec SD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e2.29\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.0-8.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e4.68\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e10.77\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e2.35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.0-63.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e\u003cem\u003eV\u003c/em\u003e\u0026thinsp;=\u0026thinsp;268, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.592\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePosterior swallow kPa SD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e3.04\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.77\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e2.75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.5\u0026ndash;7.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.96\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e2.88\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e3.20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.5\u0026ndash;10.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e\u003cem\u003et\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.537, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.067\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAnterior swallow kPa SD\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e3.30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.89\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e3.00\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.5\u0026ndash;6.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e3.79\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e2.57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e3.55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e\u003cp\u003e0.0-9.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e\u003cem\u003et\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.012, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.159\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e\u0026mdash;\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\u003cb\u003eComparison of marked and unmarked means and SDs\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe first set of analyses compared the marked and unmarked conditions in terms of the mean and standard deviation of the three measurements for each parameter via paired-samples t tests and Wilcoxon signed-rank tests. The comparisons of the marked and unmarked conditions for each parameter are illustrated via boxplots in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e (see and of the manuscript) with respect to the mean of the measurements and in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e (see and of the manuscript) with respect to the standard deviation of the measurements. The results of the statistical comparisons are presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e above under the column titled \u0026ldquo;Paired Comparison\u0026rdquo;. As shown in the table, none of the comparisons yielded a statistically significant result. For the posterior swallow kPa SD, however, the difference between the marked and unmarked conditions approached statistical significance, t(33)\u0026thinsp;=\u0026thinsp;1.537, p\u0026thinsp;=\u0026thinsp;0.067. This occurred because the standard deviations of the three measurements of the posterior swallow kPa parameter in the unmarked condition (M\u0026thinsp;=\u0026thinsp;3.96, SD\u0026thinsp;=\u0026thinsp;2.88) were marginally greater than those in the marked condition (M\u0026thinsp;=\u0026thinsp;3.04, SD\u0026thinsp;=\u0026thinsp;1.77). Thus, the first set of analyses did not reveal a significant difference between the two conditions in terms of the overall scores obtained for each parameter (comparison of means) or in terms of the variability in measurements within each parameter (comparison of standard deviations).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eCorrelations between the marked and unmarked means\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe second set of analyses examined the correlations between the marked and unmarked conditions in terms of the means of the three measurements for each parameter via the Pearson correlation coefficient and Spearman's rank correlation coefficient. The results of these correlation analyses are given in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e at the end of the manuscript (column titled \u0026ldquo;Correlation\u0026rdquo;). As shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e at the end of the manuscript, the marked and unmarked means exhibited a significant, large and positive correlation for each parameter, all r/ρs(32)\u0026thinsp;\u0026gt;\u0026thinsp;0.727, all ps\u0026thinsp;\u0026lt;\u0026thinsp;0.001. In parallel with the first set of analyses, the second set of analyses indicated that the two conditions (marked and unmarked) yielded similar and positively correlated scores.\u003c/p\u003e\u003cp\u003e\u003cb\u003eCorrelations between tube length and pressure/duration within the unmarked condition\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe third set of analyses examined the correlations between the raw pressure/duration measurements and the lengths of the tube for each parameter only within the unmarked condition, where the tube length is measured separately for each of the three measurements within each parameter. These analyses revealed that tube length was significantly correlated with only the posterior swallow kPa, r(100) = -0.275, p\u0026thinsp;=\u0026thinsp;0.005. This negative correlation indicates that longer tube lengths were associated with smaller pressure values for the posterior swallow parameter, as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e (see and of the manuscript). None of the other parameters (posterior strength in kPa, posterior endurance in seconds, anterior swallow in kPa) significantly correlated with tube length, all r/ρs(100)\u0026thinsp;\u0026lt;\u0026thinsp;0.099, all ps\u0026thinsp;\u0026gt;\u0026thinsp;0.325.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eReliability Analyses\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe final analyses, the fourth and fifth sets of analyses, were intended to assess test-retest reliability and interrater reliability, respectively. Both reliability results are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e (located at the end of the manuscript). The test-retest reliability analyses revealed that all the parameters exhibited significant, large and positive correlations between the two testing times, all of which were rs(12)\u0026thinsp;\u0026gt;\u0026thinsp;0.630, all ps\u0026thinsp;\u0026lt;\u0026thinsp;0.015. Finally, the interrater reliability analyses revealed that the two raters\u0026rsquo; scores were significantly correlated with posterior strength kPa, posterior swallow kPa, and anterior swallow kPa, with large effect sizes (all rs(12)\u0026thinsp;\u0026gt;\u0026thinsp;0.706, all ps\u0026thinsp;\u0026lt;\u0026thinsp;0.005). However, the two raters\u0026rsquo; scores did not significantly correlate with the posterior endurance parameter in seconds, r(12)\u0026thinsp;=\u0026thinsp;0.232, p\u0026thinsp;=\u0026thinsp;0.425. Overall, these results suggest that the procedures adopted in the current study had high test‒retest reliability for all the parameters and high interrater reliability for most of the parameters tested.\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\u003eTest-retest and interrater reliability results.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\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\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTest-retest reliability\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eInterrater reliability\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePosterior strength kPa M\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003er\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.631\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.015\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003er\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.707\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.005\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePosterior endurance sec M\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003er\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.933\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u0026thinsp;\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.232, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.425\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePosterior swallow kPa M\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003er\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.862\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u0026thinsp;\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003er\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.737\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.003\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAnterior swallow kPa M\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003er\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.869\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u0026thinsp;\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003er\u003c/b\u003e\u0026thinsp;\u003cb\u003e=\u0026thinsp;0.906\u003c/b\u003e, \u003cb\u003ep\u003c/b\u003e\u0026thinsp;\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe aim of this study was to evaluate the impact of marking the intraoral position of the IOPI bulb on the reliability and variability of tongue strength, endurance, and oropharyngeal swallow pressure measurements in healthy young adults. The results provide robust information regarding the reliability of IOPI assessments under different conditions.\u003c/p\u003e\u003cp\u003eIn Hypothesis 1, no significant difference was found between the mean scores of each parameter in the marked and unmarked conditions. When this result was considered alongside test‒retest analyses by the first rater and the findings from the two raters, it supported the reliability of the commonly used measurement technique in the literature. This finding is consistent with a previous study by Adams et al., which demonstrated high reliability of tongue strength measurements via the IOPI device in healthy adults when standardized instructions were followed, even in the absence of physical markings on the bulb. The same study reported that the reliability of tongue endurance measurements was generally unsatisfactory and highlighted the need for further research [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Similarly, in our study, the results of the endurance measurements taken by the two raters were not significantly correlated, whereas significant and strong correlations were observed for other parameters related to tongue strength and swallowing. Vanderwegen et al. emphasized that anatomical landmarks and visual feedback can guide consistent bulb placement, particularly in anterior positions, and reduce dependence on physical cues [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAccording to Hypothesis 2, it was anticipated that the standard deviations (SDs) of the measurements in the unmarked condition would show greater variability than those in the marked condition would. Although no statistically significant difference was found, the difference in SD for posterior tongue measurements approached statistical significance between the marked and unmarked conditions. This occurred because the standard deviations of the three measurements of the posterior tongue in the unmarked condition were slightly larger than those in the marked condition (see Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e at the end of the manuscript). This finding aligns with our second hypothesis and reflects previous concerns raised by Palmer et al.; they noted that inconsistent bulb positioning in the posterior oral cavity, owing to anatomical complexity (i.e., variations in both neural input and peripheral muscle structures), might lead to less reproducible results (Kays et al.) [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOur data indicate that unmarked conditions may result in greater variability, particularly in tasks involving the posterior tongue. Given the narrower and more variable surface contact area in the oropharynx, slight deviations in bulb positioning can affect pressure values. This finding emphasizes the clinical importance of ensuring reproducible placement through anatomical guidance, consistent instructions, or physical markers, especially when monitoring a patient\u0026rsquo;s progress over time.\u003c/p\u003e\u003cp\u003eIn the analyses conducted under Hypothesis 3, the relationships between pressure and duration measurements obtained in the unmarked condition and tube length were evaluated. In this context, a significant negative correlation was found only for posterior tongue pressure with tube length. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e (see and of the manuscript), the relationship between increased tube length and decreased pressure values is consistent with the near-significant values observed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e (located at the end of the manuscript). This finding points to the need for further investigation into the relationship between oropharyngeal swallowing pressure measurements and tube length with larger sample sizes. In previous studies in the literature, the length of the portion of the tube remaining in the mouth was not measured; only pressure values under marked conditions were recorded [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan additionalcitationids=\"CR12 CR13 CR14\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Therefore, systematically measuring the length of the IOPI device\u0026rsquo;s disposable part when positioned at different locations is essential for future research. Additionally, investigating the effects of different bulb placements on measurements during both effortful and spontaneous swallowing is recommended.\u003c/p\u003e\u003cp\u003eIn anterior tongue swallowing pressure measurements, the ease of bulb placement enhances the feasibility of these measurements; however, similar ease is not achievable for measurements in the posterior tongue region. In this context, the inclusion of tube length as a measurement parameter could increase measurement accuracy.\u003c/p\u003e\u003cp\u003e This study was based on swallowing guidelines and bulb placement instructions that are widely accepted for validity in the literature, and tube lengths were also measured and included in the analyses. In the test‒retest analyses conducted to assess the reliability of measurement errors due to placement, both raters obtained similar results, indicating that the measurement differences were not due to rater error.\u003c/p\u003e\u003cp\u003e In our study, after providing instructions for oropharyngeal swallowing measurements, participants were expected to perform the task with maximum effort. These instructions were given to prevent swallowing at lower pressure levels [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] and to achieve the maximum possible swallowing pressure. If the \u0026ldquo;swallow strongly\u0026rdquo; instruction had not been provided, some participants would have naturally swallowed forcefully, whereas others would not have exerted any effort. Thus, by emphasizing strong swallowing in our study, weak swallowing was excluded.\u003c/p\u003e\u003cp\u003eFor the measurements conducted via the IOPI, the instructions were followed in accordance with the literature, and the results obtained support the reliability of these measurement procedures.\u003c/p\u003e\u003cp\u003eTest‒retest reliability analyses revealed high and statistically significant positive correlations across all the parameters. In the interrater reliability analyses, high levels of agreement were found between the raters' measurements for the posterior tongue strength, posterior, and anterior tongue swallowing pressure parameters. However, the interrater agreement for posterior tongue endurance measurements was not statistically significant. This finding aligns with previous studies that indicated low reliability in endurance measurements [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. The literature includes studies in which endurance measurements were repeated once [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], twice [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], or three times. In this study, three measurements were taken for each parameter to evaluate the difference between the conditions with and without taping.\u003c/p\u003e\u003cp\u003eThe results obtained indicate that the current protocols are particularly strong in terms of test‒retest reliability and that interrater reliability is adequate for most parameters.\u003c/p\u003e\u003cp\u003e\u003cb\u003eLimitations\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe total duration of the study was limited to a single 45-minute session. During the first 15 minutes, the inclusion criteria for the participants were assessed, and the remaining time was used to perform measurements with the IOPI. In the selection of measured parameters, posterior tongue strength and endurance parameters were chosen because of the greater likelihood of tube misplacement or slippage during each measurement. In contrast, anterior tongue strength and endurance measurements were not utilized because tube placement could easily be achieved, and the limited time could lead to fatigue as measurements were prolonged. However, both posterior and anterior tongue swallowing pressures were measured for swallowing pressure assessments. As a result, no differences in length were observed for anterior placement, whereas a decrease in pressure was noted as length increased for posterior placement. These measurements are considered important in supporting the norms for oropharyngeal swallowing pressure and clinical decision-making processes during oropharyngeal swallowing therapies. Therefore, further studies with larger sample sizes, particularly those involving posterior tongue measurements with length measurements, are needed to provide more robust findings.\u003c/p\u003e\u003cp\u003eSince it was not part of the scope of our study, the sex differences between the marked and unmarked measurements were not examined. However, this variable may be explored in future studies. Additionally, in this study, a comparison between the length of the disposable part inside the mouth in the unmarked condition and the lengths in the marked condition was not conducted. Future research should systematically evaluate the differences between these two conditions. While some studies involving marked measurements exist, these studies did not compare them with unmarked measurements or consider tube length. As a result, studies conducted on participant groups with similar characteristics, where both conditions are evaluated together, are needed. In this study, data obtained from 34 healthy individuals under both marked and unmarked conditions were evaluated. Future research, including larger samples with different age and sex groups, is expected to provide more generalizable findings, especially regarding oropharyngeal swallowing pressures.\u003c/p\u003e\u003cp\u003eDuring the preparation of this work, the authors used DeepL and ChatGPT to improve language and readability. After using this tool/service, the authors reviewed and edited the content as needed and take full responsibility for the content of the publication.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAcknowledgment\u003c/h2\u003e\u003cp\u003eThis study was supported by XX under the XX No. XX. The funds that were taken were used solely for the purchase of the IOPI bulbs.\u003c/p\u003e\u003cp\u003ePhotographs and visuals: XX prepared the photos and graphics used in the research and gave permission for their use. Permission was obtained from XX for the use of facial photos in our research.\u003c/p\u003e\u003cp\u003eWe thank them for their support of our project.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eIowa Oral Performance Instrument Model 3.2, IOPI PRO User Manual Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://iopimedical.com/wp-content/uploads/2025/03/800-3101-09_EN-IOPI-Pro-User-Manual-English.pdf\u003c/span\u003e\u003cspan address=\"https://iopimedical.com/wp-content/uploads/2025/03/800-3101-09_EN-IOPI-Pro-User-Manual-English.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePalmer PM, Neel AT, Sprouls G, Morrison L (2010) Swallow characteristics in patients with oculopharyngeal muscular dystrophy. 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The Journals of Gerontology Series A: Biological Sciences and Medical Sciences. 51(5):M247\u0026ndash;250. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/gerona/51a.5.m247\u003c/span\u003e\u003cspan address=\"10.1093/gerona/51a.5.m247\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eUtanohara Y, Hayashi R, Yoshikawa M, Yoshida M, Tsuga K, Akagawa Y (2008) Standard values of maximum tongue pressure taken using newly developed disposable tongue pressure measurement device. Dysphagia Sep 23(3):286\u0026ndash;290\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Istanbul Medipol University","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"IOPI, tongue strength, tongue endurance, swallowing pressure, measurement reliability","lastPublishedDoi":"10.21203/rs.3.rs-7053677/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7053677/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e\u003cp\u003eTo compare posterior tongue strength, endurance, and anterior / posterior swallowing pressures via the IOPI under marked and unmarked conditions and to examine correlations between intraoral tube length and pressure/duration in the unmarked condition.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eA crossover design was used with 34 healthy adults (aged 20\u0026ndash;39 years). Each parameter was measured three times under both conditions. Normality was tested via the Shapiro‒Wilk test. Pearson or Spearman correlations were used depending on the distribution. Paired t tests, Wilcoxon tests, and correlation analyses were conducted (R v4.1.2). Reliability was assessed in a subsample.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eNo significant differences were found between the marked and unmarked means (all ps\u0026thinsp;\u0026gt;\u0026thinsp;0.07), although the posterior swallowing pressure SD approached significance (t(33)\u0026thinsp;=\u0026thinsp;1.537 p\u0026thinsp;=\u0026thinsp;0.067). Strong positive correlations were observed between conditions (all r/ps\u0026thinsp;\u0026gt;\u0026thinsp;0.727, ps\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Posterior swallowing pressure was negatively correlated with tube length (r\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.275, p\u0026thinsp;=\u0026thinsp;0.005). Test\u0026ndash;retest (all rs\u0026thinsp;\u0026gt;\u0026thinsp;0.63, ps\u0026thinsp;\u0026lt;\u0026thinsp;0.015) and interrater reliability (all rs\u0026thinsp;\u0026gt;\u0026thinsp;0.706, ps\u0026thinsp;\u0026lt;\u0026thinsp;0.005) were high, except for endurance (r\u0026thinsp;=\u0026thinsp;0.232, p\u0026thinsp;=\u0026thinsp;0.425).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eMarking did not significantly affect outcomes, but tube length may influence posterior swallowing pressure. The protocol showed high reliability.\u003c/p\u003e","manuscriptTitle":"Comparison of IOPI Use Technique under Two Different Conditions for Measuring Oropharyngeal Swallowing Pressure, Tongue Strength and Endurance in Healthy Young Adults.","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-08 06:22:16","doi":"10.21203/rs.3.rs-7053677/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"59a9a550-10ee-41f9-bd0a-2a72c1e43e4a","owner":[],"postedDate":"July 8th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":51087840,"name":"Audiology \u0026 Speech-Language Pathology"},{"id":51087841,"name":"Head \u0026 Neck Surgery"}],"tags":[],"updatedAt":"2025-07-08T06:22:16+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-08 06:22:16","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7053677","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7053677","identity":"rs-7053677","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}