Electrically Evoked Stapedius Reflex Threshold Research Articles

Maximum acceptable level for the determination of ECAP and ESRT in a paediatric population

Objectives Two of the most used objective measures are electrically evoked action potentials (ECAPs) and electrically evoked stapedius reflex thresholds (ESRTs). Although stimuli used for these measures differ considerably, both measures are influenced by subjective loudness percept. We focus on the subjective maximum acceptable loudness (MAL) to investigate if loudness sensitivity varied along the electrode array during ECAP recordings. In addition, we explored how the MAL reached during an ECAP recording related to the postoperative ESRT. Methods Uni- and bilaterally implanted young CI users (n = 15, average age = 9 y, age range 3–18 y) underwent ECAP and ESR recordings using the clinical software MAESTRO (MED-EL, Innsbruck, Austria) and a commercially available immittance instrument (PATH MEDICAL GmbH, Germering, Germany). Results Loudness tolerance during ECAP recordings was lowest at the two apical-most electrode contacts (number 1 and 2). There was a moderate correlation between the MAL achieved during ECAP recordings and ESR maximum stimulation amplitudes. (r: 0.44344). Conclusions ECAP recordings should commence at basal or medial contacts to increase the users’ comfort and loudness tolerance, especially in young CI users. A higher maximum stimulation appears to increase the chance of the automatic determination of ECAP thresholds for all electrode contacts.

Outcome of Cochlear Implantation in Children with Auditory Neuropathy-A Dual Case Study

Objectives: The aim of this study is to compare the outcome of cochlear implantation in two pediatric auditory neuropathy cases. Methods: Two cases with auditory neuropathy were taken. Case 1 was 10 year old male. Case 2 was 11 year old male. In preoperative assessment both have bilateral severe to profound sensory-neural hearing loss. Case 1 was implanted by MED-EL using sonata Ti100 opus 2 processor. Case 2 was implanted using MED-EL using sonata Ti100 opus 2 processor. Both cases were given auditory verbal therapy. Both cases attended auditory verbal therapy for a period of 2 years. In postoperative assessment for each individual subject, electrically evoked compound action potentials (ECAPs), electrically evoked stapedius reflex threshold (ESRT), and electrically evoked auditory brainstem response (EABR) thresholds were determined. The following questionnaire extended receptive expressive emergent language scale (E-REELS) , Categories of Auditory Performance (CAP) score, Speech Intelligibility Rating (SIR) scale, Meaningful Auditory-Integration Scale (MAIS) and Meaningful Use of Speech Scale (MUSS) are scales were administered. Results: In the postoperative assessment, ECAP, ESRT, EABR, MUSS, MAIS shows that case 1 with auditory neuropathy have better performance than case 2. Conclusion: It is essential that all possible complications and postoperative performance should be considered in cochlear implantation for auditory neuropathy individuals

Normative eSRT Value among MED-EL Pediatric Population in Indonesia

Introduction: Early stimulation of the auditory sense is essential for the development of language and speech. In children with a cochlear implant, the most common issue is whether the hearing has been optimized or not, as they are still unable to provide reliable feedback regarding their hearing ability. Thus, electrically evoked stapedius reflex threshold (ESRT) based fitting has been used as one of the available methods in programming a cochlear implant (CI) audio processor. As eSRT is an objective test, patient cooperation was not needed making it especially beneficial for children with CI who have limitations in providing feedback. Now that eSRT has been applied commonly almost worldwide, the goal of this study is to determine the normative value of eSRT among the pediatric population in Indonesia. Methods: A total of 32 pediatric CI users in the age range 3 - 11 years implanted with Med-El cochlear implant were included in this study. ESRT was performed during follow-up mapping between September 2021 and January 2022 in the Med-El Indonesia hearing center. Results: The result of the present study showed an average normative value of 20.55 qus. This finding is consistent with the values obtained in previous studies. Conclusion: The result found can be used as a valuable indicator of average optimised MCL among the pediatric population.

Effect of Electrode to Modiolus Distance on Electrophysiological and Psychophysical Parameters in CI Patients With Perimodiolar and Lateral Electrode Arrays.

To investigate the intracochlear position of the latest Cochlear Nucleus 532 electrode array compared with the straight Nucleus 522 and the precurved 512 arrays and determine the effect of the electrode-modiolus distance on electrically evoked compound action potential, C-levels, electrically evoked stapedius reflex thresholds (ESRTs), and impedances. Postoperative high-resolution cone beam computational tomography images of 30 patients with Cochlear Nucleus 532, 522, and 512 implants were evaluated using the Comet (Cochlea Measurement Tool) program to determine the distance between the 22 individual electrode contacts and the medial wall. ESRTs were documented intraoperatively and electrophysiological as well as psychophysical parameters were measured at multiple time points including the first fitting after the initial activation. The electrode-modiolus distance in perimodiolar arrays is uniformly small across the array, whereas in a straight electrode carrier it varies significantly along the length of the array. Electrically evoked compound action potential thresholds and C-levels are larger with increased distance to the modiolus. Impedances and stapedius reflex thresholds do not differ significantly between the arrays. Our results show that the electrode position has a significant effect on both electrophysiological and psychophysical parameters, while impedances and ESRTs are not impacted. Novel tools can be used in the evaluation of high resolution cone beam computational tomography images to determine individual electrode-modiolus distances after cochlear implantation. The results of this study suggest that the correlations between electrode-modiolus distance and electrophysiological and psychophysical parameters are not sufficiently strong to adjust CI-fitting based on imaging data.

Correlation between behaviorally measured comfort (c) levels and electrically evoked stapedius reflex thresholds (ESRT) in children with unilateral cochlear implant

Introduction: Decrease in the lower age limit for paediatric cochlear implantation and increasing records of cochlear implantation in children with associated impairments demand quick and easily available objective measurements to provide MAP in these children as their speech and language ability may not be adequate to provide clear cut explanation about comfort level. Providing adequate amount of acoustic stimulation in this golden period of life (i.e. 0-2 years) is important in ensuring the proper utilization of acoustic cues. Findings of adult population cannot be directly applied to younger children and till date there is no Indian study reporting relationship between Electrically Evoked Stapedial Reflex Thresholds (ESRT) and behavioural Comfort levels, especially in pediatric population. Aim: The present study aimed to assess the correlation between behaviorally measured comfort (C) levels and Electrically Evoked Stapedius Reflex Thresholds (ESRT) in children with unilateral cochlear implant. Method: Children (n=40) with age range of 4-12 years, who received the same type of CI and electrode configuration, were selected for the study. Participants were divided into two groups – younger and older - based on their chronological age. Behavioural C-level measurement and ESRT measurement were done after tympanometry for both the groups. Correlation between the two measures was obtained and comparison between the two groups was done. Results and discussion: Recorded ESRT was consistently higher than the behaviorally obtained C-level for both the groups. The correlation between ESRT and C-level varies from moderate to very strong and strong to very strong for the younger and older groups respectively. No statistically significant difference was found between the correlations for the two age groups. Conclusions: High correlations were found between the ESRT and behaviorally obtained C-levels. Thus ESRT can be utilized as a tool for programming in younger implant recipients.

The Value of Electrically Evoked Stapedius Reflex in Determining the Maximum Comfort Level of a Cochlear Implant

One of the most important steps for good user performance with a cochlear implant (CI) is activation and programming, aimed at determining the dynamic range. In adults, current levels are determined by psychophysical measures. In babies, small children, or individuals with multiple disorders, this procedure requires techniques that may provide inconsistent responses because of auditory inexperience or the age of the child, making it a very difficult process that demands the collaboration of both the patient and the family. To study the relationship between the electrically evoked stapedius reflex threshold (ESRT) and maximum comfort level for stimulating electrodes (C-level) in postoperative CI users. Cross-sectional analytical observational case series study. We assessed 24 patients of both sexes, aged between 18 and 68 yr, submitted to CI surgery. Otoscopy and immittance. Next, an implant speech processor connected to an Itautec® computer containing the manufacturer's software (custom sound Ep 3-2) was used, as well as an AT 235h probe inserted into the ear contralateral to the CI to capture the stapedius reflex, obtaining electrically evoked stapedius reflex thresholds. Data from the last programming, defining C-levels for each electrode studied, were extracted from the databank of each patient. The manual decay function of the AT 235h middle ear analyzer was used to observe ESRT response in a same window for a longer response capture time. Electrodes 22, 16, 11, 6, and 1 were tested when active, with the aim of using electrodes over the entire length of the CI, and ESRT was considered present when compliance was ≥0.05 ml. Stimuli, in current units, were always initiated at 20 cu above the C-level. The analysis of variance parametric test, Tukey's honest significant difference test, the t-test, Wilcoxon nonparametric test, and the Kolmogorov-Smirnov test examined whether significant relationships existed between these other factors. The results demonstrate that all the electrodes selected for the study exhibited higher mean reflex threshold values than their mean C-level counterparts. However, there was no significant difference between them, for electrodes 1, 6, 11, and 16. The data provided allow the use of ESRT to define C-level values and make it possible to stipulate a correction factor ranging between 6 and 25.6 electrical units. The use of electrically evoked stapedius reflex thresholds can help the team in charge of programming CIs, making the process faster and safer, mainly for infants, small children, or individuals with multiple disorders.

Postoperative objective detecting techniques for cochlear implant children with inner ear malformation

ObjectivesThis study aims to investigate the changing characteristics and rules of electrically-evoked auditory brainstem response (EABR), electrically-evoked stapedius reflex threshold (ESRT) and neural response telemetry (NRT) after cochlear implant in children with inner ear malformation, and guide postoperative equipment debug. MethodsA total of 88 children with either normal cochlea (control group) or inner ear malformation (test group) received Australian 24 multi-channel cochlear implants. The EABR, ESRT and NRT thresholds at different time points within one year postoperatively and behavioral responses (T-level and C-level) after one year were detected. Furthermore, the changing characteristics and rules of these thresholds were analyzed. ResultsThe EABR, ESRT and NRT thresholds were all significantly higher at all time points in the test group than in the control group, but the general changing trends were similar. Particularly, these thresholds worsened at low frequencies and improved at high frequencies. Furthermore, EABR, ESRT and NRT thresholds gradually increased during the one year postoperative period. In addition, an extremely significant correlation was found between EABR and T-level and between ESRT and C-level, but a less significant correlation was found between NRT threshold and T-level in both groups. ConclusionsThe postoperative changes in characteristics and rules of EABR, ESRT and NRT thresholds among cochlear implant children with inner ear malformation were all the same as those with normal cochlea. Thus, these thresholds can be used to guide the postoperative equipment debug for cochlear implants into patients with inner ear malformation.

Cochlear implantees: Analysis of behavioral and objective measures for a clinical population of various age groups

IntroductionAs of 2014 more than 1200 patients have received a cochlear implant (CI) at Oslo University Hospital (OUS) and approximately half of them have been children. The data obtained from these patients have been used to develop a comprehensive database for a systematic analysis of several objective measurements and programming measurements. During the past 10 years, we have used an objective measurements protocol for our CI surgeries. Our intra-operative protocol includes: Evoked Compound Action Potentials (ECAP), visually observed Electrically evoked Stapedius Reflex Threshold (ESRT), and electrode impedances. Post-operative (Post-OP) programming sessions typically begin 4–6 weeks after surgery and continue on a scheduled basis. The initial programming data include threshold levels (T-levels) and comfortable levels (C-levels) for the different patient age groups. In this study, we compared initial stimulation levels and stimulation levels after at least 1 year of CI with objective measurements obtained intra-operatively.MethodThis study focused on the development of a comprehensive database of detailed intra-operative objective measures and post-OP programming measurements from a group of 296 CI patients who received the same type of CI and electrode configuration (Cochlear® Corporation CI with Contour® electrode). This group included 92 bilateral CI patients. Measurements from 388 CI devices were studied. Patients were divided into 5 different age groups at the age of implantation: 0–2, 2–5, 5–10, 10–20, and above 20 years in order to investigate age-related differences in programming levels and objective measurements. For the comparison analysis we used T- and C-levels obtained after the last day of initial programming and also after at least 1 year implant use. These programming levels were then correlated with some of the intra-operative objective measurements.ResultsT-levels were found to be the lowest for the youngest patient group and increased with age. C-levels varied within age groups and frequency range. Patients above 20 years of age had the highest comfort levels in the low to mid-frequencies (electrodes 22–8) and the lowest comfort levels in the high-frequency range (electrodes 1–7). Correlation coefficients between intra-operative objective measurements and programming levels were found to be in the range of no correlation to moderate correlation. Adult patients had the most significant correlation coefficients between ECAP thresholds and T-levels in the low frequencies. The younger patients aged 10–20 years and 5–10 years had more significant correlations in the higher frequency channels compared to the other age groups. Intra-operative visually observed ESRTs and electrode impedances were not significantly correlated with initial or stable programming levels for the children or adults.ConclusionAnalyzing initial and follow-up mapping levels from previous patients is very important for a CI Center in terms of quality control. The mean T/C-levels reported in this study can provide guidance to our programming audiologists and help them determine the initial programming levels to be stored in the speech processor, especially for very young patients. Unfortunately intra-operative objective measures in our study, such as ECAP, ESRT, and electrode impedances did not provide statistically significant correlations that may help to predict the programming T- and C-levels for all patients. However, we have observed cases where the intra-operative objective measures of ESRT and TECAP profiles were very similar to an individual's MAP profile. It was not possible, however, to determine why some patients did not have an objective measures profile that was similar to their programming levels profile.

Unilateral cochlear implant use promotes normal-like loudness perception in adolescents with childhood deafness.

Behavioral measures of cochlear implant (CI) device stimulation levels can be difficult to obtain in individuals with limited or no hearing experience. Loudness measures are particularly challenging. It would therefore be useful to have a battery of objective and behavioral measures to determine CI stimulation levels in listeners with childhood deafness. In the present study, the authors characterized loudness growth in 20 adolescents: 8 with normal hearing and 12 CI participants with pre/perilingual bilateral sensorineural hearing loss. They asked (1) do adolescent CI users with childhood deafness experience similar increases in loudness as their peers with normal hearing? and (2) can loudness be predicted by objective measures of auditory activity? The authors hypothesized that loudness perception would be significantly different between CI and normal-hearing groups and that it would correlate with objective measures. CI users were recruited from the Cochlear Implant Program at The Hospital for Sick Children and all had used unilateral Nucleus CIs for at least 2 years. The dynamic range for each participant was defined as the difference between the behavioral threshold and the electrically evoked stapedius reflex (ESR) threshold. Loudness growth was assessed within this range behaviorally on a continuous visual scale and objectively with physiological measures. Auditory brainstem responses (ABRs) and ESRs were recorded in both groups and electrically evoked compound action potentials (ECAPs) of the auditory nerve were recorded in addition in CI listeners. The regression line slopes of ECAP and ABR amplitude growth functions were then calculated and compared with behavioral loudness growth slopes in the upper portion (40-100%) and lower portion (0-40%) of the dynamic range. Electrical pulse stimuli (in CI users) and acoustic clicks (in normal-hearing participants) were presented within each participant's dynamic range. The mean dynamic range in CI listeners was more variable than in normal-hearing individuals. Despite this difference, loudness at the ESR threshold was not significantly different in CI adolescents from their normal-hearing peers, and CI users exhibited normal-like loudness growth. There was a significantly positive correlation between ECAP amplitude growth and loudness growth in CI users in the upper portion of the dynamic range, while ABR wave V amplitude growth was not related to loudness growth in either group. We confirmed that the ESR threshold is a good measure of comfortably loud levels in adolescents with cochlear implants and their normal-hearing peers. Adolescents using CIs show normal-like rates of loudness growth on average, despite having highly variable dynamic ranges of hearing. Individual rates of loudness growth in the upper dynamic range in CI users can be predicted by the rate of amplitude growth of the ECAP. Thus, the rate of neural recruitment with increasing CI current is important for loudness perception in pre/perilingually deaf listeners and should be considered when programming their CIs.

Toward a method for programming balanced bilateral cochlear implant stimulation levels in children

ObjectivesIn the present study, we investigated differences in stimulation levels between bilateral cochlear implants (CIs) in children and compared these to previously recorded measures of balanced input. We hypothesized that differences in stimulation levels between two CI: (1) will be observed both in behavioral and objective measures, and (2) can help to provide bilateral stimulation levels that are perceived as balanced.MethodParticipants were 19 children who received bilateral CIs sequentially. Behaviorally determined minimum and maximum stimulation levels from the first (CI-1) and second (CI-2) CIs at an apical electrode (#20) were compared with thresholds of the electrically evoked compound action potential (ECAP) of the auditory nerve and electrically evoked stapedius reflex (ESR).ResultsAll four measures were found to be greater when evoked from CI-1 than CI-2 and the dynamic range between behavioral measures was reduced in CI-2 relative to CI-1. Significant correlations were found between differences in behavioral and objective measures; as differences in T-levels between CI-1 and CI-2 increased, so did the differences in ECAP thresholds and a similarly positive relationship was found between C-level differences and ESR threshold differences. Differences in ECAP thresholds between CI-1 and CI-2 were significantly correlated with balanced bilateral levels.DiscussionChildren using two different Nucleus CIs often require different stimulation levels on either side. Although lower levels were needed on the side more recently implanted with newer technology, the dynamic range of input provided on the second side was reduced relative to the more experienced side. Differences in behavioral measures between CI-1 and CI-2 can be partially predicted by objective measures. ECAP thresholds show the best promise for helping to provide balanced bilateral CI input in children.

Evaluation of Objective Test Techniques in Cochlear Implant Users With Inner Ear Malformations

The aim of the study was to compare results of objective test techniques in cochlear implant users with inner ear malformations and incomplete partition anomalies with types I and II and to show which techniques should be used in the evaluation and fitting of cochlear implant users with inner ear malformations. Retrospective clinical study. The subjects in the control group were selected randomly from cochlear implant users with normal cochlea. Inclusion criteria for patients group were having inner ear malformation for the study group and at least 1 year cochlear implants use for both groups. For each individual subject, electrically evoked compound action potentials (ECAPs), electrically evoked stapedius reflex threshold (ESRT), and electrically evoked auditory brainstem response (EABR) thresholds were determined. These tests were applied after a normal cochlear implant fitting session. There were 20 subjects in inner ear malformation group and 15 subjects in the control group. For each subject, 6 intracochlear electrodes, representing apical, middle, and basal array of intracochlear electrode, were used. In the cochlear malformation group, percentage of acquired ECAP thresholds was 25%. However, in the control group, percentage of ECAP was 74%. Similarly with ECAP, percentage of ESRT in the cochlear malformation group was 17.5%, and that in the control group was 90%. The difference between these percentages was statistically significant. Both current levels and latencies of EABR wave V were significantly different from each other for the inner ear malformation group and the control group. For statistical analysis, Mann-Whitney U test for 2 independent samples, Kruskal-Wallis analysis and Dunn's Z test were used. For the inner ear malformation group, EABR is a more applicable objective test technique when compared with ECAP and ESRT.

Intraoperative electrically evoked stapedius reflex thresholds in children undergone cochlear implantation: Round window and cochleostomy approaches

Objectives To study the best electrically stimulation in cochlear implant surgery with round window (RW) and Promontory cochleostomy approaches with electrically evoked stapedius reflex thresholds (ESRT) intraoperatively. Methods Thirty-nine children underwent CI surgery were included for this study. The surgical procedures consisted of RW and Promontory cochleostomy. ESRT for each 1st, 3rd, 6th and 12th electrodes ( E) were determined. Statistical evaluation was done for the comparison of the thresholds and duration times for both groups. Results The duration times of ESRT for E1, E3, E6 and E12 electrodes was shorter in RW group compared with the Promontory group ( p < 0.05). The statistical evaluation of ESRT measurements of E1, E3, E6 found p < 0.001 and E12 electrode p < 0.05 in RW group. ESRT measurements were recorded at lower threshold in the RW group compared with the Promontory group. Conclusion The duration of electrically stimulation thresholds were shorter in RW group. ESRT measurements were recorded at lower threshold in the RW group compared with the Promontory group. RW insertion offers best electrically stimulation relative to electrode insertion via a promontory cochleostomy.

F031 Relationship between Maximum Comfort Levels (MCL) and electrically evoked stapedius reflex thresholds (ESRT)

Peak ground accelerations, computed from sliding of objects during the 1969 Banja Luka earthquakes in Bosnia and Herzegovina (former Yugoslavia) are computed assuming that the ground motion consists of simple rectangular or sinusoidal pulses. The results show good agreement with observed macroseismic estimates of shaking based on the Mercalli–Cancani–Sieberg (MCS) intensity scale. The results are also in compliance with recorded accelerations during the 1973–1986 period and with recent probabilistic hazard analyses for the Banja Luka region.

Investigations into electrically evoked stapedius reflex measures and subjective loudness percepts in the MED-EL COMBI 40+ cochlear implant

For several years there has been interest in using objective measures to set channel-specific upper programming limits when programming the speech processor of cochlear implant users. The present study aims to add to previous reports by examiningcorrelations between electrically evoked stapedius reflex threshold (ESRT) and a range of psychophysical loudness estimates in a group of 22 adult users of the MED-EL COMBI 40+ system. Thirteen of the 15 subjects (87%) had recordable stapedius reflexes.Psychophysical measures of threshold, maximum comfort level (MCL) and maximum acceptable loudness (MAL) were recorded. Results showed that mean ESRT was closest to the MCL using 500 ms burst ('MCL500'), with MCL50 (MCL using 50 ms burst) and MAL500 some 2 dB and MAL50 3 dB higher. Correlations between ESRT and the behavioural loudness judgements were highest for MCL500 (R = 0.69, p < 0.001) and slightly less for MAL500. These results confirm the ease of measuring ESRT in a clinicalsetting and that a high level of confidence can be placed on the use of these measures for setting processor maps in the absence of behavioural data.

Toward a Battery of Behavioral and Objective Measures to Achieve Optimal Cochlear Implant Stimulation Levels in Children

Children require audible and comfortable stimulation from their cochlear implants immediately after device activation. To accomplish this, a battery of objective measures may be needed that could include the electrically evoked stapedius reflex (ESR), compound action potential from the auditory nerve (ECAP), and/or auditory brain stem response (EABR). In the present study, the following specific research questions were asked: In children using cochlear implants, 1) Can the ECAP, EABR, and ESR be recorded at the time of cochlear implantation? 2) What is the feasibility of measuring the ECAP, EABR, and the ESR repeatedly without the use of sedation over the first year of implant use? 3) Do ECAP, EABR, and ESR thresholds or behavioral measures change over time? 4) What is the relation between ECAP, EABR, and ESR thresholds and behavioral measures of threshold and comfortably loud levels? In 68 children, ECAP, EABR, and ESR responses as well as behavioral measures of stimulation threshold and maximum stimulation were recorded at regular intervals over the first year of implant use. In each child, responses were recorded to electrical pulses provided by three different electrodes along the implanted array. Visual inspections of the stapedius reflex (V-ESR) evoked by activation of the same three electrodes at the time of surgery were performed in an additional 20 children. ECAP and EABR measures were obtained in more than 84% of electrodes tested and 89% of children tested both in the operating room at the time of implant surgery (OR) and after surgery in nonsedated children. ESRs were recorded by using immittance measures in more than 65% of electrodes tested and 67% of children tested by 3 mo of implant use, but this technique was less successful in the OR and during early stages of device use. V-ESRs and ECAP thresholds were higher in the OR than ESRs and ECAPs at postoperative recording times. EABR and ECAP thresholds did not significantly change over the first 6 and 12 mo of implant use, respectively, whereas ESR thresholds increased. Behavioral measures of threshold decreased over time, whereas maximum stimulation levels rose over time. Behavioral measures of threshold and loudness were highly correlated at all test times. ECAP, EABR, and behavioral measures were lower when evoked by an electrode at the apical end of the implanted array than by more basal electrodes. Behavioral thresholds could be predicted mainly by ECAP thresholds, whereas maximum stimulation levels could best be predicted by ESR thresholds; both were significantly affected by the age at implantation. A combination of nonbehavioral measures can aid in the determination of useful cochlear implant stimulation levels, particularly in young children and infants with limited auditory experience. These measures can be made in the operating room and can be repeated after surgery when needed. Correction factors to predict threshold stimulation levels should be based on ECAP thresholds or EABR thresholds if necessary. Correction factors should be made for at least one apical and mid-array electrode, should take into account the age of the child, and may have to be revised during the first year of implant use. Maximum stimulation levels may be best determined by using the ESR.

Relationship of intraoperative electrically evoked stapedius reflex thresholds to maximum comfortable loudness levels of children with cochlear implants: Relaciones entre los umbrales transquirürgicos del reflejo estapedial eléctricamente evocado y los niveles máximos de sonoridad agradable en niños con implantes cocleares

Previous studies of the relationship between the intraoperatively obtained electrically evoked stapedius reflex threshold (ESRT) and the maximum comfortable loudness (MCL) values used to program the speech processor of cochlear implant (CI) patients have indicated that ESRTs provide an inexact estimate of MCL. In order to determine whether this estimate might be more exact for electrodes in different parts of the electrode array, we studied the electrode-specific relationships between ESRT and MCL in 29 Med-El Combi 40+ and 25 Nucleus Cl 24 M patients after first fitting of the speech processor and 2 and 6 months later. The MCL values were mostly less than the ESRT values, but increased progressively over the first 6 months, reaching 83% and 72% of the ESRT values, on average, across all electrodes for the Med-El and Nucleus systems respectively. The population variation across electrodes decreased over the 6-month observation period and was least for the apical half of the array, for which the correlation coefficients of regressions between ESRT and MCL were around 0.65 for both systems. These results indicate that estimates of MCL values from the ERST are more accurate for the apical half of the intra-cochlear array and could then be described by an offset value plus an increase of MCL by 0.62 and 0.53 of ESRT for the Med-El and Nucleus systems, respectively.SumarioLos estudios previos de la relatión entre los umbrales del reflejo estapedial evocados eléctricamente en forma transquirúrgica (ERST) y los máximos niveles agradables de sonoridad (MCL), utilizados para programar los procesadores del lenguaje de pacientes con implantes cocleares (CI), han indicado que el ERST aporta una medida inexacta del MCL. Con el fin de determinar si las estimaciones podrían ser más exactas para las terminates en diferentes partes del sistema de electrodos, estudiamos las relaciones electrodo-específicas entre el ESRT y el MCL en 29 pacientes con implante Combi 40+ de Med-El, y 25 pacientes con Nucleus CI 24M, luego de la primera activatión del procesador de lenguaje, así como 2 y 6 meses más tarde. Los valores del MCL fueron habitualmente menores que los valores para el ESRT, pero se incrementaron progresivamente durante los primeros 6 meses, alcanzando un 83% y un 72% de los valores para el ESRT, en todos los electrodos de los sistemas Med-El y Nucleus respectivamente. La variatión entre los electrodos de esta poblacion disminuyó a lo largo de un periodo de 6 meses de observatión, y fue menor para la mitad apical del sistema de electrodos, para la cuál la correlation de los coeficientes de regresión entre el ESRT y el MCL estuvo en alrededor de 0.65 para ambos sistemas. Estos resultados indican que los valores estimados de MCL basados en el ERST son más exactos en la mitad apical intracoclear del sistema de electrodos, y que podrian ser descritos por un valor balanceado (offset value) mas un incremento del MCL del 0.62 y 0.53 del valor del ERST para. los sistemas Med-El y Nucleus, respectivamente.