List Equivalency and Critical Differences of a Mandarin Bamford-Kowal-Bench Sentence in Babble Noise Test for Adults and Preschool Children With Normal Hearing.

PURPOSE: The purpose of this study was to determine the speech recognition equivalence of Mandarin Bamford-Kowal-Bench (BKB) sentence lists with adults and children with normal hearing. METHOD: A total of 32 lists, each of nine sentences, were compiled from a corpus of BKB-like sentences with paired babble in Mandarin. Interlist equivalence, critical differences, and sensitivity of performance to signal-to-noise ratio (SNR) were examined. Experiment 1 included 64 native Mandarin-speaking adults with normal hearing. Experiment 2 included 54 native Mandarin-speaking children with normal hearing aged 4-6 years. RESULTS: Among the 32 sentence lists, 28 lists were confirmed to be equivalent in adults, with a mean SNR required for 50% correct (SNR50) of -5.9 ± 0.1 dB, a mean slope of 22.3%/dB ± 1.5%/dB, and a grand 95% critical difference subsequently calculated as 27.2% for score. From the 28 equivalent lists, 27 lists were selected and observed to be equivalent in children, with a mean SNR50 threshold of -2.0 ± 0.2 dB, a mean slope of 15.8%/dB ± 1.1%/dB, and a grand 95% critical difference of 24.6% for score. CONCLUSIONS: The Mandarin BKB sentences in babble noise test offers an opportunity for clinicians and researchers to assess speech understanding in adults and preschool children in an efficient manner. For comparisons of performance in different test conditions, 28 equivalent lists are available for adults and 27 equivalent lists for preschool children. The 95% critical difference values can be used for total percentage correct or SNR for 50% performance. Future work will examine the clinical utility for school-age children and children who are deaf and hard of hearing. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.24400066.

Investigation of hearing loss in elderly vertigo and dizziness patients in the past 10 years.

Background: Vertigo and hearing loss are both prevalent in the elderly. This study retrospectively analyzed hearing test results from elderly patients experiencing vertigo and dizziness at ENT outpatient over a 10-year period, in order to study the patterns of hearing loss in this patient population. Methods: Nine thousand three hundred eighty four patients over 50 years old underwent retrospective collection and screening of outpatient diagnosis, pure tone audiometry, acoustic immittance measurement (tympanogram) and auditory brainstem response (ABR) test. The patient's audiograms are divided into 7 subtypes according to a set of fixed criteria. Meanwhile, K-Means clustering analysis method was used to classify the audiogram. Results: The Jerger classification of tympanogram in elderly patients with vertigo and dizziness showed the majority falling under type A. The leading audiogram shapes were flat (27.81% in right ear and 26.89% in left ear), high-frequency gently sloping (25.97% in right ear and 27.34% in left ear), and high-frequency steeply sloping (21.60% in right ear and 22.53% in left ear). Meniere's disease (MD; 30.87%), benign recurrent vertigo (BRV; 19.07%), and benign paroxysmal positional vertigo (BPPV; 15.66%) were the most common etiologies in elderly vestibular diseases. We observed statistically significant differences in hearing thresholds among these vestibular diseases (P < 0.001). K-Means clustering analysis suggested that the optimal number of clusters was three, with sample sizes for the three clusters being 2,747, 2,413, and 4,139, respectively. The ANOVA statistical results of each characteristic value showed P < 0.001. Conclusion: The elderly patients often have mild to moderate hearing loss as a concomitant symptom with vertigo. Female patients have better hearing thresholds than males. The dominant audiometric shapes in this patient population were flat, high-frequency gently sloping, and high-frequency steeply sloping according to a set of fixed criteria. This study highlights the need for tailored strategies in managing hearing loss in elderly patients with vertigo and dizziness.

[Clinical case analysis and literature review of mandibulofacial dysostosis with microcephaly syndrome].

Objective:To explore the clinical diagnosis, otological treatment and molecular etiology in a rare syndromic hearing loss case characterized by mandibulofacial dysostosis with microcephaly（MFDM）. Methods: The proband underwent detailed history collection, systematic physical examination and phenotypic analysis, as well as audiological examination, chest X-ray, temporal bone CT and brain MRI and other imaging examinations. The blood DNA of the proband and his parents was extracted and tested by the whole exom sequencing. The EFTUD2-related-MFDM literatures published by the end of 2020 were searched and sifted in PubMed and CNKI databases,the clinical characteristics of MFDM were summarized. Results:In this study, the patient presented with hypoplasia of auricle, micrognathia, microcephaly, developmental retardation, severe sensorineural hearing loss in both ears, and developmental malformation of middle and inner ear. Genetic analysis revealed a de novo deletion c.623_624delAT in EFTUD2 gene. According to the clinical features and genetic test results, the patient was diagnosed as MFDM. In order to solve the problem of hearing loss, the patient was further performed bilateral cochlear implantation, and part of the electrodes responded well during and after operation. Conclusion:This is the first domestic reported case of MFDM caused by EFTUD2 gene mutation. The key problem of cochlear implantation for this kind of patient is to avoid damaging the malformed facial nerve during the operation.The effect of speech rehabilitation after cochlear implant operation is related to many factors such as intelligence development of the patients.

[The development of vocabulary capability at 2-year follow-up in the prelingual deaf children with cochlear implants].

OBJECTIVE: To investigate the development of early vocabulary capability in the prelingual deaf children after cochlear implantation (CI) , and to study the feasibility of current Chinese assessment procedures about language development for hearing-impaired children. METHOD: A total of 56 cases with severe-to-profound prelingual deaf children were participated in this study. The vocabulary development of CI children were evaluated by trained audiologists using the vocabulary assessment tools: Chinese communicative development inventory (CCDI) and mandarin expressive and receptive vocabulary test (MERVT). The questionnaire assessed by parents or guardians answered the questionnaire; vocabulary tests were evaluated by children accompanied with audiologists. Patients were assessed before operation and in 2 years after switch-on. RESULT: With the rehabilitation, early post-operative vocabulary development gradually improved. The vocabulary increased with an increase in the duration of CI use, and the receptive vocabulary developed earlier than the expressive ones. CONCLUSION: After 2 years of CI use, the child partly developed the vocabulary capability. Children's vocabulary test, CCDI and MERVT test, is an important index to evaluate the development of children's language ability after cochlear implantation. Vocabulary test, together with auditory and speech perception assessment procedures, constitute a more complete auditory-speech-language evaluation system for Chinese children after cochlear implants.

[Development of early auditory and speech perception skills within one year after cochlear implantion in prelingual deaf children].

OBJECTIVE: To investigate the development of early auditory capability and speech perception in the prelingual deaf children after cochlear implantation, and to study the feasibility of currently available Chinese assessment instruments for the evaluation of early auditory skill and speech perception in hearing-impaired children. METHODS: A total of 83 children with severe-to-profound prelingual hearing impairment participated in this study. Participants were divided into four groups according to the age for surgery: A (1-2 years), B (2-3 years), C (3-4 years) and D (4-5 years). The auditory skill and speech perception ability of CI children were evaluated by trained audiologists using the infant-toddler/meaningful auditory integration scale (IT-MAIS/MAIS) questionnaire, the Mandarin Early Speech Perception (MESP) test and the Mandarin Pediatric Speech Intelligibility (MPSI) test. The questionnaires were used in face to face interviews with the parents or guardians. Each child was assessed before the operation and 3 months, 6 months, 12 months after switch-on. RESULTS: After cochlear implantation, early postoperative auditory development and speech perception gradually improved. All MAIS/IT-MAIS scores showed a similar increasing trend with the rehabilitation duration (F=5.743, P=0.007). Preoperative and post operative MAIS/IT-MAIS scores of children in age group C (3-4 years) was higher than that of other groups. Children who had longer hearing aid experience before operation demonstrated higher MAIS/IT-MAIS scores than those with little or no hearing aid experience (F=4.947, P=0.000). The MESP test showed that, children were not able to perceive speech as well as detecting speech signals. However as the duration of CI use increased, speech perception ability also improved substantially. However, only about 40% of the subjects could be evaluated using the most difficult subtest on the MPSI in quiet at 12 months after switch-on. As MCR decreased, the proportion of children who could be tested using the MPSI reduced. CONCLUSIONS: Within one year after CI, children develop early auditory and speech perception capabilities with time. Chinese versions of the IT-MAIS/MAIS, MESP and MPSI are useful instruments to document early auditory and speech perception skills in children after CI implantation.

Determination of benefits of cochlear implantation in children with auditory neuropathy.

BACKGROUND: Auditory neuropathy (AN) is a recently recognized hearing disorder characterized by intact outer hair cell function, disrupted auditory nerve synchronization and poor speech perception and recognition. Cochlear implants (CIs) are currently the most promising intervention for improving hearing and speech in individuals with AN. Although previous studies have shown optimistic results, there was large variability concerning benefits of CIs among individuals with AN. The data indicate that different criteria are needed to evaluate the benefit of CIs in these children compared to those with sensorineural hearing loss. We hypothesized that a hierarchic assessment would be more appropriate to evaluate the benefits of cochlear implantation in AN individuals. METHODS: Eight prelingual children with AN who received unilateral CIs were included in this study. Hearing sensitivity and speech recognition were evaluated pre- and postoperatively within each subject. The efficacy of cochlear implantation was assessed using a stepwise hierarchic evaluation for achieving: (1) effective audibility, (2) improved speech recognition, (3) effective speech, and (4) effective communication. RESULTS: The postoperative hearing and speech performance varied among the subjects. According to the hierarchic assessment, all eight subjects approached the primary level of effective audibility, with an average implanted hearing threshold of 43.8 ± 10.2 dB HL. Five subjects (62.5%) attained the level of improved speech recognition, one (12.5%) reached the level of effective speech, and none of the subjects (0.0%) achieved effective communication. CONCLUSION: CIs benefit prelingual children with AN to varying extents. A hierarchic evaluation provides a more suitable method to determine the benefits that AN individuals will likely receive from cochlear implantation.

[Study of auditory brainstem response to speech sounds in sex differences].

OBJECTIVE: To study the electrophysiological characteristics of the Auditory Brainstem Response to Speech Sounds (s-ABR) in healthy adults, and then analyze its relationship between noise speech recognition ability and sex. METHOD: We accessed the auditory brainstem response to a synthesized stop-consonant speech syllable / da/in 40 native-Chinese speech adults. Timing components of the response were compared between males and females to determine which aspects of the response are affected by sex. The relationship of the slope between the onset peak (V) and though (A) (V/A slope) and the noise speech recognition ability was analyzed. RESULT: A dissimilarity between males and females was observed in the response to the component that change rapidly over time(P< 0.05). The other peaks latency except (P < 0.01) was different between gender, the remaining peaks did not have statisticals differences (P > 0.05). Noise speech recognition and the V/A slope was negatively correlated (r = 0.478, P < 0.05), which indicated that the greater slope of V/A, the lower of the speech recognition threshold under noise. CONCLUSION: The verbal components change rapidly over time, and high-frequency consonants evoked neural response obviously affected by gender. In the slower changing, lower frequency information in the stimulus was minimally affected by sex. The subjects with better abilities of processing transient and rapid information can show lower noise speech recognition threshold.

NRT test in auditory neuropathy patients with cochlear implants.

CONCLUSION: In patients with auditory neuropathy (AN), waveforms of neural response telemetry (NRT) could be present, showing characteristics of low incidence, low differentiation, and large variation. OBJECTIVE: To study the characteristics of NRT in AN patients who had received cochlear implants (CIs). METHODS: NRT data for seven AN patients who had received Nucleus CIs were retrospectively analyzed. Twenty-one CI implantees with sensorineural hearing loss (SNHL) were included as the control group. The incidence of electrically evoked compound action potentials (ECAPs), threshold of wave N1, and amplitude of N1-P2 in the AN group were analyzed and compared between groups. RESULTS: The intraoperative incidence of valid ECAPs in the AN group was 42.9%, and the postoperative incidence was 66.7%, both of which were lower than those in the SNHL group, which were 95.2% and 100%, respectively. NRT in the AN group showed larger variation and lower differentiation than in the SNHL group. Wilcoxon's non-parametric test results indicated no significant difference between AN and SNHL groups in either the threshold of ECAP or N1-P2 amplitude.

Preliminary performance of cochlear implants in post-lingual patients with auditory neuropathy.

CONCLUSIONS: Auditory restoration can be obtained by using cochlear implants (CIs) in post-lingual patients with auditory neuropathy (AN). However, improvements in postoperative speech recognition for these patients varied. OBJECTIVES: The primary purpose of this study was to assess the postoperative performances of two post-lingual AN patients after receiving CIs. METHODS: Two post-lingual AN patients received unilateral CIs and the efficacy of the implants was then evaluated. One patient was female with bilateral mid-severe hearing loss and received an implant at age 28 years. The second patient was male with severe hearing loss and he received an implant at age 15 years. The postoperative performance for both patients was evaluated. RESULTS: After using the CI for 6 months, the hearing ability of both subjects was improved by the CI with an average post-implant threshold of 35 dB and 44 dB, respectively. The woman made significant progress in speech recognition with an open-set spondee recognition score of 55% and sentence recognition in quiet score of 90%. Sentence recognition in noise scores were 94% (SNR = +10 dB), 88% (SNR = +5 dB), and 80% (SNR = 0 dB). The boy achieved improved recognition scores for monosyllables (40%) and disyllables (26%), but poor sentence recognition both in quiet (0%) and in noise (0%).

[Speech and pitch perception with the new fine structure speech coding strategy].

OBJECTIVE: To assess the performance of the new fine structure processing strategy(FS4) compared to the previous generation coding strategy HDCIS. METHOD: Twelve post-lingual hearing-impaired cochlear implant users were included. FS4 and HDCIS were compared in music pitch perception and speech perception test. RESULT: Acute comparison between FS4 and HDCIS showed that FS4 performed as well as HDCIS in speech perception tests, and outperformed HDCIS in music pitch perception. CONCLUSION: Results indicate that FS4 performs better than HDCIS in music perception. Differences between the two strategies were not significant for speech test.

Development of a corpus of Mandarin sentences in babble with homogeneity optimized via psychometric evaluation.

OBJECTIVE: To develop a corpus of sentences in babble noise that is suitable for Mandarin-speaking children. Two experiments were conducted with specific aims of (1) developing sentence material that is grammatically and semantically within the linguistic abilities of children; and (2) improving the efficiency of the test by equalizing the relative intelligibility of individual items in sentences. DESIGN AND STUDY SAMPLE: Sentences were extracted from spoken material of Chinese children aged between 4 and 5 years of age. The sentences were tested for intelligibility in a four-talker babble by 96 adult native speakers of Mandarin. Psychometric functions were generated, and used for adjusting signal-to-noise ratios of individual items by varying the level of the time-locked babble to equate intelligibility of the target speech. These adjusted stimuli were tested for intelligibility using a different group of 64 adult listeners. RESULTS: The signal-to-noise ratio for 50% correct was not different before and after adjustments (- 6.1 dB and - 6.0 dB, respectively). However, there was a significant reduction in standard deviation from 2.3 dB before adjustment to 1.1 dB after adjustment (p < 0.05). CONCLUSIONS: The experiments established a corpus of Mandarin BKB-like sentences with four-talker babble as competing noise, in which the test items' homogeneity was optimized via psychometric evaluation (HOPE).

[Preliminary clinical research of cochlear implantation in elderly and pre-elderly patients with profound hearing loss].

OBJECTIVE: To explore the safety and efficacy of cochlear implantation among elderly patients with severe to profound hearing loss. METHODS: Eight pre-elderly and elderly patients with an medium age of 58 years who suffered from bilateral severe to profound sensorineural hearing loss received cochlear implantation between November 2008 and November 2009. The patients' tolerance to implant surgery and the occurrence of complications were observed. Three months after switch-on, aided threshold and speech performance were measured. RESULTS: The surgery was uneventful in all cases with normal intraoperative neural response telemetry elicited. Three months after switch-on, average aided threshold across speech frequencies was 35 - 50 dB HL measured in sound field with warble tone. The results of speech audiometry showed large variation between individuals. Some patients achieved good performance in monosyllable recognition test, disyllables threshold test and sentences recognition test under both bubble noise and quiet conditions. CONCLUSIONS: Pre-elderly and elderly patients can endure a state of general anesthesia for cochlear surgery without complications. Cochlear implant can provide reconstruction of speech recognition capabilities for elderly patients suffering from severe to profound hearing loss. Cochlear implantation can improve the quality of life of elderly patients with hearing loss.

[Study of aural rehabilitation in post-lingual deafened patients with multi-channel cochlear implant].

OBJECTIVE: To seek a convenient and effective method through subjective psychophysical measurements and CAP/SIR assessment. To compare the discrimination of rehabilitation between post-lingual and pre-lingual deafened patients. METHOD: Thirty-one post-lingual cochlear implantees and 59 pre-lingual cochlear implantees, the warble tone and CAP/SIR were assessed. The discrimination of threshold levels, comfortable levels and dynamic range between post-lingual and pre-lingual deafened patients in same electrodes were compared. RESULT: There was no statistic difference in warble tone, T-levels, C-levels and dynamic range in same electrodes implant after 6 months implant (P>0.05). The score of CAP and SIR in post-lingual deafened patients were more prominent. CONCLUSION: CAP and SIR is a kind of convenient and effective method to assess the ability of aural and oral. There was no discrimination in warble tone, T-levels, C-levels and dynamic range in same electrodes implant, but the ability of aural and oral in post-lingual deafened patients were more prominent.

Electrode interaction in cochlear implant recipients: comparison of straight and contour electrode arrays.

The degree of overlap among cochlear nerve fibers stimulated by different electrodes results in electrode interaction, which has been shown to have a significantly deleterious effect on speech recognition performance in multi-electrode cochlear implant users. The Nucleus CI24R(CS) Contour array, which lies substantially closer to the modiolus than the CI24M straight array, is expected to exhibit narrower excitation patterns. The neural response telemetry (NRT) 3.0 software provides a method of measuring the spread of neural excitation by presenting the masker and probe pulses on different intra-cochlear electrode bands. Nine pairs of children, using Nucleus CI24M/CI24R(CS) cochlear implants with a similar etiology and duration of deafness, insertion depth, age of implantation and loudest acceptable presentation level (LAPL) in NRT sessions, participated in the study. Profiles of the spread of neural excitation stimulated at the LAPL at 3 probe locations were examined for each pair of the 2 types of electrode array. The spread of neural excitation with respect to array type and location revealed significant effects (p < 0.001; p = 0.002) and no interaction between array type and probe location (p = 0.559). The results demonstrated that the Contour array improved electrode discrimination, especially for the electrodes at the basal end of the cochlea. The findings have implications for future electrode array design and current implant mapping strategies.

[Mutation of Gap junction protein beta 2 gene and treatment outcome of cochlear implantation in cochlear implantation recipients].

OBJECTIVE: To investigate the Gap junction protein beta 2 (GJB2) gene mutation in cochlear implantation (CI) recipients and the treatment outcome of CI in the CI recipients with GJB2 gene mutation. METHODS: Peripheral blood samples were collected from 253 CI recipients with autosomal recessive non-syndromic hearing impairment (NSHI), 174 males and 79 females, aged (8 +/- 9) (112 months-52.7 years), and 301 children with normal hearing level as controls. PCR was used to detect the GJB2 mutations. The auditory threshold with CI and speech recognition of the CI recipients with GJB2 mutation were compared with those of the CI recipients without GJB2 mutation (control group). Questionnaire survey, with meaningful auditory integration scale (MAIS), categories of auditory performance (CAP), and speech intelligibility rating (SIR), was used for young infants. RESULTS: Sixty-seven of the 253 CI recipients (26.5%) were found to have GJB2 mutations. One novel mutation, GJB2 235delC/598G > A, was identified. The detection rates of GJB2 mutations in the CI recipients were significantly higher than those among the controls (all P < 0.05). The postoperative outcomes of CI in both the GJB2 gene mutation positive and negative groups were very good, however, without significant differences among these 2 groups (all P > 0.05). CONCLUSION: GJB2 gene mutation is one of the major causes for CI recipients with autosomal recessive NSHI. The treatment outcomes of CI recipients with GJB2 gene mutations under 7 years old are satisfying.

[Mapping of gene underlying autosomal dominant non-syndromic hearing loss(DFNA)].

Hereditary non-syndromic sensorineural hearing loss is a genetically highly heterogeneous group of disorders. To date, at least 50 loci for autosomal dominant non-syndromic sensorineural hearing loss (DFNA) have been identified by linkage analysis. Here we report a huge family with late onset autosomal dominant hereditary non-syndromic hearing loss. In this family, 73 of 170 family members have been conducted physical examination, pure-tone audiometry, immittance testing and auditory brainstem response testing (ABR). The results indicated that 39 of 73 tested family members have sensorineural hearing loss in various degrees. No associated visible abnormalities in other systems were found in this family. After exclusion of the 14 known DFNA loci with markers from the Hereditary Hearing Loss Homepage (URL: http://dnalab-www.uia.ac.be/dnalab/hhh), a genome wide scan was carried out using 382 highly informative microsatellite markers at approximately 9.2 cM intervals throughout the genome. Linkage analysis was carried out under a fully penetrant autosomal dominant mode of inheritance with no phenocopies. A maximum two-point LOD score of 6.69 at theta=0 was obtained for marker D14S1040. Haplotype analysis placed the locus within a 7.6 cM genetic interval defined by marker D14S1021 and D14S70, overlapping with the DFNA9 locus.

[Refractory recovery function of electrical auditory on the survival auditory nerve in cochlear implant recipients].

OBJECTIVE: To evaluate the cochlear implant recipient's electrical auditory temporal properties in order to estimate the maximum stimulating rate which can be reached when they adopted some speech coding strategies based on time mechanism, such as continuous interleaved sampling (CIS). METHODS: Thirty-eight Nucleus CI24 cochlear implant recipients were divided into 4 groups by etiology and history. Their survival auditory nerve fibers' refractory recovery time function was measured via neural response telemetry (NRT). Electrical pulses with the amplitude of recipient's loudest acceptable presentation were stimulated in mono-polar mode, with the width of 25 microseconds and the frequency of 80 Hz. Least-squares regression procedures were used to fit individual recovery functions with the equation A = C + K e(-t/tau), in which tau is the time constant of recovery from refractory state. Statistic analysis showed the relationship between the time constants of individuals and etiology as well as electrode position in the cochlea. RESULTS: Congenital deaf patient's recovery time constants were shorter than that of postnatal deaf groups of ototoxicity (P = 0.0056) and large vestibular aqueduct syndrome (P = 0.0349). There was no significant difference between the recovery time constants of congenital deaf patients and those of group with long history of deafness. The ANOVA of the recovery time constants of 5th, 10th, 15th electrode showed no significant statistical difference (P > 0.05). CONCLUSION: The recovery time constants are related with etiology. In mono-polar mode, the time constants of congenital deafness or subjects with short duration of deafness are shorter than those of postnatal deafness or subjects with long duration of deafness. Time constants do not vary systematically with electrode location along the implanted array. The reciprocal of individual electrode seems to be used in determining the maximum of stimulating rate of CIS strategy and as criteria of choosing the usable channels from 22 electrode bands.

[Rating evaluation of the effect of pre-lingual cochlear implanted's aural/oral rehabilitation by questionnaires].

OBJECTIVE: To evaluate the effect of cochlear implanted's aural/oral rehabilitation using rating evaluation method by questionnaires, to analyze the relationship between rehabilitation effect and its possible influence factors including type of implant, age at surgery, pathology, etc, and to explore the rating questionnaire method for cochlear implanted's aural/oral rehabilitation effect evaluation. METHODS: Ninety-seven pre-lingual cochlear implanted's were involved in this investigation, all of which were severe or profound deafness before implantation. Interviewed the implanted's parents or teachers, asking them to rate the implanted's aural ability objectively from 1 to 8 according to Categories of Auditory Performance (CAP) and speech producing ability from 1 to 5 according to Speech Intelligibility Rating (SIR), then analyzed the relationship between effect of aural/oral rehabilitation represented by CAP/SIR rating results and its possible 9 influence factors including type of implant, age at surgery, pathology, duration of hearing loss, hearing aid wearing, inserting length of electrodes, implanted period, rehabilitation mode and financial conditions. Univariate test and multivariate stepwise logistic regression model were used for the analysis. RESULTS: In a univariate analysis, it was confirmed that 4 factors i.e. type of implant (P = 0.0439), implanted period (P = 0.0001), rehabilitation mode (P = 0.0460) and financial conditions (0.0140) were correlated to CAP; 2 factors i.e. implanted period (P = 0.0001), rehabilitation mode (P = 0.0271) were correlated to SIR. In a multivariate analysis using stepwise logistic regression model, the more significant influence factor for CAP was implanted period and financial conditions, and for SIR was implanted period. CONCLUSIONS: Cochlear implants will be more effective for aural/oral rehabilitation of implanted's with longer implanted period. Rehabilitation mode and method contribute to the effect of rehabilitation.

[Electrically evoked compound action potential thresholds of pediatric cochlear implant recipients and its clinical application].

OBJECTIVE: To investigate the possibility of using pediatric cochlear implant mapping protocol, to estimate the psychophysical levels based on the electrically evoked compound action potential (ECAP) threshold measured with the neural response telemetry (NRT) capabilities of cochlear corporation's CI24M device. METHODS: ECAP amplitude growth functions were regressed via NRT 3.0 software to determine ECAP threshold. 6 pediatric cochlear implant recipients' ECAP thresholds 1, 2 and 3 months after surgery were compared, meanwhile, intraoperative and postoperative ECAP thresholds in 7 pediatric recipients were compared. RESULTS: The ECAP amplitude growth functions were not linear when ECAP was close to threshold or saturation. There were no significant difference among the ECAP thresholds 1, 2 and 3 months after surgery. The average intraoperative ECAP threshold of 22 electrodes was 15 CL greater than postoperative threshold. It showed high relationship between them (R2 = 0.9154). CONCLUSION: ECAP threshold should be determined by regression of data from linear part of amplitude growth function. Only one NRT trial should be assessed when mapping protocol based on ECAP threshold to estimate pediatric map parameter. The intraoperative ECAP threshold can act as C-level at the initial mapping. Key words cochlear implant, electrically evoked compound action potential, mapping.

[A longitudinal study of electrode impedance in nucleus 24M cochlear implant users].

OBJECTIVE: The primary goal of this study was to examine changes that may occur in electrode impedance over time in cochlear implant users. Secondary goal was to determine the timetable of mapping for patients who were cooperative quite well in psychophysical test. METHOD: Sixteen patients implanted with Nucleus CI24M participated in this study. The impedance of electrode was measured intra-operatively, at initial stimulation, and at each mapping visits. Statistical analysis was conducted to assess how the changes occurring over time. RESULT: There was a significant increase in electrode impedance from the intra-operative test to initial stimulation, and a significant decrease in impedance from initial stimulation to the following visit. The impedance values remained stable for approximately 2-4 months after initial stimulation. CONCLUSION: The results suggest that electrode-tissue interface gradually tend to remain stable. If a patient cooperates quite well in psychophysics test, the psychophysical levels for the map should be stable after 2 to 4-month mapping.