Effects of Bilateral Cochlear Implantation on Binaural Listening Tasks for Younger and Older Adults.

PURPOSE: This study investigated the objective and subjective benefit of a second cochlear implant (CI) on binaural listening tasks of speech understanding in noise and localization in younger and older adults. We aimed to determine if the aging population can utilize binaural cues and obtain comparable benefits from bilateral CI (BIL_CI) when compared to the younger population. METHODS: Twenty-nine adults with severe to profound bilateral sensorineural hearing loss were included. Participants were evaluated in two conditions, better CI (BE_CI) alone and BIL_CI using AzBio and Bamford-Kowal-Bench (BKB) sentence in noise tests. Localization tasks were completed in the BIL_CI condition using a broadband stimulus, low-frequency stimuli, and high-frequency stimuli. A subjective questionnaire was administered to assess satisfaction with CI. RESULTS: Older age was significantly associated with poorer performance on AzBio +5 dB signal-to-noise ratio (SNR) and BKB-speech in noise (SIN); however, improvements from BE_CI to BIL_CI were observed across all ages. In the AzBio +5 condition, nearly half of all participants achieved a significant improvement from BE_CI to BIL_CI with the majority of those occurring in patients younger than 65 years of age. Conversely, the majority of participants who achieved a significant improvement in BKB-SIN were adults >65 years of age. Years of BIL_CI experience and time between implants were not associated with performance. For localization, mean absolute error increased with age for low and high narrowband noise, but not for the broadband noise. Response gain was negatively correlated with age for all localization stimuli. Neither BIL_CI listening experience nor time between implants significantly impacted localization ability. Subjectively, participants report reduction in disability with the addition of the second CI. There is no observed relationship between age or speech recognition score and satisfaction with BIL_CI. CONCLUSION: Overall performance on binaural listening tasks was poorer in older adults than in younger adults. However, older adults were able to achieve significant benefit from the addition of a second CI, and performance on binaural tasks was not correlated with overall device satisfaction. The significance of the improvement was task and stimulus dependent but suggested a critical limit may exist for optimal performance on SIN tasks for CI users. Specifically, older adults require at least a +8 dB SNR to understand 50% of speech postoperatively; therefore, solely utilizing a fixed +5 dB SNR preoperatively to qualify CI candidates is not recommended as this test condition may introduce limitations in demonstrating CI benefit.

Decoding Billing Practices in Cochlear Implant Programs.

OBJECTIVES: The purpose of this study was to examine current cochlear implant (CI) billing practices across CI audiologists in the United States, to determine if CI audiologists are following the National Correct Coding Initiative (NCCI) edits, and to assess the CI audiologist's exposure to billing education. DESIGN: A 48-question survey was electronically distributed to and completed by audiologists who bill for CI services. Demographic data including work setting, population served, years of experience, number of CI patients managed per week, and exposure to billing education were collected. Data were analyzed to identify codes and modifiers used to bill for commonly performed CI procedures such as unilateral and bilateral CI programming, preoperative and postoperative testing, and objective measures. RESULTS: Data were obtained from 96 audiologists. The majority (86.3%, n = 82) of respondents agreed or strongly agreed they understand billing and coding practices for cochlear implants and 94.7% (n = 89) rated themselves as somewhat to highly efficient when performing these practices. Only 16.8% (n = 16) of respondents reported receiving formal training for practice management, and half of the respondents (51.1%, n = 48) reported unfamiliarity with national billing guidelines. Those who received formal training reported higher billing efficiency. Wide variability was seen for various billing scenarios. Billing questions were presented, and answers were coded as correct or incorrect based on the NCCI edits. Respondents who reported higher agreement with understanding billing and who received formal training scored better on common billing questions related to the NCCI edits. CONCLUSIONS: Most CI audiologists rated themselves as efficient in billing; however, wide variance in billing practices was observed. Incorporating practice management and current billing education into daily practice and into audiology training programs is essential to clinic efficiency, practice management, and CI program viability. CI audiologists should be knowledgeable about appropriate billing practices to ensure long-term sustainability of programs.

Cochlear implant programming: a global survey on the state of the art.

The programming of CIs is essential for good performance. However, no Good Clinical Practice guidelines exist. This paper reports on the results of an inventory of the current practice worldwide. A questionnaire was distributed to 47 CI centers. They follow 47600 recipients in 17 countries and 5 continents. The results were discussed during a debate. Sixty-two percent of the results were verified through individual interviews during the following months. Most centers (72%) participated in a cross-sectional study logging 5 consecutive fitting sessions in 5 different recipients. Data indicate that general practice starts with a single switch-on session, followed by three monthly sessions, three quarterly sessions, and then annual sessions, all containing one hour of programming and testing. The main focus lies on setting maximum and, to a lesser extent, minimum current levels per electrode. These levels are often determined on a few electrodes and then extrapolated. They are mainly based on subjective loudness perception by the CI user and, to a lesser extent, on pure tone and speech audiometry. Objective measures play a small role as indication of the global MAP profile. Other MAP parameters are rarely modified. Measurable targets are only defined for pure tone audiometry. Huge variation exists between centers on all aspects of the fitting practice.

American Cochlear Implant Alliance Task Force: Recommendations for Determining Cochlear Implant Candidacy in Adults.

The indications for cochlear implantation have expanded over time due to evidence demonstrating identification and implantation of appropriate cochlear implant (CI) candidates lead to significant improvements in speech recognition and quality of life (QoL). However, clinical practice is variable, with some providers using outdated criteria and others exceeding current labeled indications. As a results, only a fraction of those persons who could benefit from CI technology receive it. This document summarizes the current evidence for determining appropriate referrals for adults with bilateral hearing loss into CI centers for formal evaluation by stressing the importance of treating each ear individually and a "revised 60/60 rule". By mirroring contemporary clinical practice and available evidence, these recommendations will also provide a standardized testing protocol for CI candidates using a team-based approach that prioritizes individualized patient care. This manuscript was developed by the Adult Cochlear Implantation Candidacy Task Force of the American Cochlear Implant Alliance using review of the existing literature and clinical consensus. LEVEL OF EVIDENCE: N/A Laryngoscope, 134:S1-S14, 2024.

Cochlear Implant Referral Criteria for the Spanish-Speaking Adult Population.

OBJECTIVE: To evaluate the effectiveness of the "60/60 Guideline" in a diverse patient population. STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. PATIENTS: Data were collected for adult patients (18 years and older) who underwent a cochlear implant evaluation (CIE) between January 2016 and March 2021. MAIN OUTCOME MEASURES: Development of the "60/60 Guideline" has provided better clarity on when to refer English-speaking patients for a CIE. Our study evaluated the effectiveness of this referral tool in the Spanish-speaking population. RESULTS: In our group of patients who underwent a traditional CIE (n = 402), 209 met unaided and aided traditional cochlear implant (CI) candidacy criteria. Of the 193 individuals who did not meet both components of traditional candidacy criteria, a majority met the aided component (86%) but only 4.6% met the unaided component. When applying the 60/60 Guideline to patients who met traditional criteria, there is a sensitivity rating of 84.7% and a specificity index of 50.3%. For English and Spanish speakers who met traditional criteria but did not meet the 60/60 Guideline, a majority (83.3% English, 87.5% Spanish) had a better ear word recognition score (WRS) greater than 60%, suggesting the unaided WRS is the more restrictive component of the "60/60 Guideline." CONCLUSION: Application of the "60/60 Guideline" is an effective method to identify potential CI candidates in the English-speaking population; however, it was less effective in the Spanish-speaking population. Spanish-speaking adults should be referred for a CIE when better ear pure tone average is greater than 60 dB hearing loss, regardless of their unaided WRS. This study highlights the need for inclusion of nonlinguistic test measures in the CI referral criteria and test battery to reduce CI access barriers for patients who speak a language other than English.

Catchment Profile of Large Cochlear Implant Centers in the United States.

OBJECTIVE: To characterize the catchment area and patient profile of large cochlear implant (CI) centers in the United States. STUDY DESIGN: Multi-institutional retrospective case series. SETTING: Tertiary referral CI centers. METHODS: Patients who underwent CI surgery at 7 participating CI centers between 2015 and 2020 were identified. Patients' residential zip codes were used to approximate travel distances and urban vs rural residential areas. RESULTS: Over the 6-year study period (2015-2020), 6313 unique CI surgical procedures occurred (4529 adult, 1784 pediatric). Between 2015 and 2019, CI procedures increased by 43%. Patients traveled a median 52 miles (interquartile range, 21-110) each way; patients treated at rural CI centers traveled greater distances vs those treated at urban centers (72 vs 46 miles, P < .001). Rural residents represented 61% of the patient population and traveled farther than urban residents (73 vs 24 miles, P < .001). Overall, 91% of patients lived within a 200-mile radius of the institution, while 71% lived within a 100-mile radius. In adults, multiple regression analysis redemonstrated an association between greater travel distances and (1) older age at the time of CI and (2) residential rural setting (both P < .001, r2 = 0.2). CONCLUSIONS: While large CI centers serve geographically dispersed populations, most patients reside within a 200-mile radius. Strategies to expand CI utilization may leverage remote programming, telemedicine, and strategic placement of new centers and satellite clinics to ameliorate travel burden.

Can Electrocochleography Help Preserve Hearing After Cochlear Implantation With Full Electrode Insertion?

OBJECTIVES: To evaluate the utility of intracochlear electrocochleography (ECochG) monitoring during cochlear implant (CI) surgery on postoperative hearing preservation. STUDY DESIGN: Prospective, randomized clinical trial. SETTING: Ten high-volume, tertiary care CI centers. PATIENTS: Adult patients with sensorineural hearing loss meeting the CI criteria who selected an Advanced Bionics CI. METHODS: Patients were randomized to CI surgery either with audible ECochG monitoring available to the surgeon during electrode insertion or without ECochG monitoring. Hearing preservation was determined by comparing preoperative unaided low-frequency (125-, 250-, and 500-Hz) pure-tone average (LF-PTA) to postoperative LF-PTA at CI activation. Pre- and post-CI computed tomography was used to determine electrode scalar location and electrode translocation. RESULTS: Eighty-five adult CI candidates were enrolled. The mean (standard deviation [SD]) unaided preoperative LF-PTA across the sample was 54 (17) dB HL. For the whole sample, hearing preservation was "good" (i.e., LF-PTA change 0-15 dB) in 34.5%, "fair" (i.e., LF-PTA change >15-29 dB) in 22.5%, and "poor" (i.e., LF-PTA change ≥30 dB) in 43%. For patients randomized to ECochG "on," mean (SD) LF-PTA change was 27 (20) dB compared with 27 (23) dB for patients randomized to ECochG "off" ( p = 0.89). Seven percent of patients, all of whom were randomized to ECochG off, showed electrode translocation from the scala tympani into the scala vestibuli. CONCLUSIONS: Although intracochlear ECochG during CI surgery has important prognostic utility, our data did not show significantly better hearing preservation in patients randomized to ECochG "on" compared with ECochG "off."

MicroRNA Profiling in the Perilymph of Cochlear Implant Patients: Identifying Markers that Correlate to Audiological Outcomes.

HYPOTHESIS: MicroRNA (miRNA) expression profiles from human perilymph correlate to post cochlear implantation (CI) hearing outcomes. BACKGROUND: The high inter-individual variability in speech perception among cochlear implant recipients is still poorly understood. MiRNA expression in perilymph can be used to characterize the molecular processes underlying inner ear disease and to predict performance with a cochlear implant. METHODS: Perilymph collected during CI from 17 patients was analyzed using microarrays. MiRNAs were identified and multivariable analysis using consonant-nucleus-consonant testing at 6 and 18 months post implant activation was performed. Variables analyzed included age, gender, preoperative pure tone average (PTA), and preoperative speech discrimination (word recognition [WR]). Gene ontology analysis was performed to identify potential functional implications of changes in the identified miRNAs. RESULTS: Distinct miRNA profiles correlated to preoperative PTA and WR. Patients classified as poor performers showed downregulation of six miRNAs that potentially regulate pathways related to neuronal function and cell survival. CONCLUSION: Individual miRNA profiles can be identified in microvolumes of perilymph. Distinct non-coding RNA expression profiles correlate to preoperative hearing and postoperative cochlear implant outcomes.

Screening Strategies for Deafness Genes and Functional Outcomes in Cochlear Implant Patients.

OBJECTIVES: To review the current state of knowledge about the influence of specific genetic mutations that cause sensorineural hearing loss (SNHL) on cochlear implant (CI) functional outcomes, and how this knowledge may be integrated into clinical practice. A multistep and sequential population-based genetic algorithm suitable for the identification of congenital SNHL mutations before CI placement is also examined. DATA SOURCES, STUDY SELECTION: A review was performed of the English literature from 2000 to 2019 using PubMed regarding the influence of specific mutations on CI outcomes and the use of next-generation sequencing for genetic screening of CI patients. CONCLUSION: CI is an effective habilitation option for patients with severe-profound congenital SNHL. However, it is well known that CI outcomes show substantial inter-patient variation. Recent advances in genetic studies have improved our understanding of genotype-phenotype relationships for many of the mutations underlying congenital SNHL, and have explored how these relationships may account for some of the variance seen in CI performance outcomes. A sequential genetic screening strategy utilizing next-generation sequencing-based population-specific gene panels may allow for more efficient mutation identification before CI placement. Understanding the relationships between specific mutations and CI outcomes along with integrating routine comprehensive genetic testing into pre-CI evaluations will allow for more effective patient counseling and open the door for the development of mutation-specific treatment strategies.

Electrophysiology and genetic testing in the precision medicine of congenital deafness: A review.

BACKGROUND: Congenital hearing loss is remarkably heterogeneous, with over 130 deafness genes and thousands of variants, making for innumerable genotype/phenotype combinations. Understanding both the pathophysiology of hearing loss and molecular site of lesion along the auditory pathway permits for significantly individualized counseling. Electrophysiologic techniques such as electrocochleography (ECochG) and electrically-evoked compound action potentials (eCAP) are being studied to localize pathology and estimate residual cochlear vs. neural health. This review describes the expanding roles of genetic and electrophysiologic evaluation in the precision medicine of congenital hearing loss.The basics of genetic mutations in hearing loss and electrophysiologic testing (ECochG and eCAP) are reviewed, and how they complement each other in the diagnostics and prognostication of hearing outcomes. Used together, these measures improve the understanding of insults to the auditory system, allowing for individualized counseling for CI candidacy/outcomes or other habilitation strategies. CONCLUSION: Despite tremendous discovery in deafness genes, the effects of individual genes on neural function remain poorly understood. Bridging the understanding between molecular genotype and neural and functional phenotype is paramount to interpreting genetic results in clinical practice. The future hearing healthcare provider must consolidate an ever-increasing amount of genetic and phenotypic information in the precision medicine of hearing loss.

Partial deafness cochlear implantation at the University of Kansas: techniques and outcomes.

BACKGROUND: One of the most significant recent advances in cochlear implantation is the implantation of patients with residual hearing. These patients have a downsloping sensorineural hearing loss with poor speech discrimination and perform poorly with standard amplification. Studies using a variety of different electrode designs have demonstrated that it is possible to implant an inner ear and preserve residual hearing. Initial studies have demonstrated that a combination of residual acoustic hearing in the low frequencies with electrical stimulation in the mid- to high frequencies resulted in superior hearing performance in background noise. PURPOSE: The objective of this study was to determine the effect of electrode insertion depth on hearing preservation. STUDY SAMPLE: Eighteen patients with mild to severe hearing loss in the low frequencies combined with poor word recognition were recruited for the study. INTERVENTION: Cochlear implantation. DATA COLLECTION AND ANALYSIS: Pre- and postoperative hearing test, Hearing in Noise Test, and consonant-nucleus-consonant testing. Data analysis was performed with Kruskal Wallis and Mann-Whitney testing. RESULTS: In our study of 18 patients implanted with a Med-El PulsarCI100 we demonstrated the ability to preserve residual hearing with implant insertion depths ranging from 20 to 28 mm, giving us the possibility of near complete cochlear frequency coverage with an implant array while preserving residual hearing. These patients performed well both in quiet and in 10 dB signal-to-noise ratio conditions. CONCLUSION: Hearing preservation was achievable even with deep implant insertion. Patients performed well in combined acoustic and electric conditions.

The impact of COVID-19 on allied health professions.

The purpose of the current study was to examine the impact of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2 or COVID-19) on allied health professionals work environment, access to personal protective equipment (PPE) and COVID-19 testing, and mental health. A 34-question survey was developed and distributed electronically to allied health professionals through listservs of professional organizations and social media groups. A total of 921 responses from allied health professionals in a variety of work settings were analyzed. The majority of allied health professionals had access to medical-grade PPE and agreed with their clinics decisions to stay open or closed. Private practices appeared to be the most negatively impacted with regards to employment in the form of pay reductions, furloughs, lay-offs, or the requirement of using paid time off. Importantly, 86% of all respondents, irrespective of employment status, reported feeling stressed with regards to changes in their work environment and transmission of the virus. However, levels of stress were dependent upon access to PPE and mental health resources. Specifically, those with access to mental health support reported lower stress levels than those without such access. These results highlight the need for continuous monitoring of mental health for allied health professionals in order to inform clinic and hospital policies for PPE and the development of brief interventions to mitigate adverse long-term mental health outcomes.

Audiology Practices in the Preoperative Evaluation and Management of Adult Cochlear Implant Candidates.

Importance: Currently, no clear guidelines exist regarding clinical testing methods for identifying adult cochlear implant (CI) candidates. Indications provided by the US Food and Drug Administration, Medicare, and private insurers are ambiguous concerning test materials and the level and mode of test presentation. This could lead to wide variability in clinical assessment and, potentially, unequal access to CIs for individuals with clinically significant hearing loss. Objective: To examine the preoperative testing methods used by audiologists in evaluating adult CI candidates across the United States. Design, Setting, and Participants: A survey assessing audiology practice patterns was created using a Research Electronic Data Capture system hosted at the University of Miami. A link to a survey (65 questions in multiple-choice or rank-order format was distributed electronically along with a request for completion to members of the American Cochlear Implant Alliance and to the Institute for Cochlear Implant Training forum. Responses were collected from January 17 to June 4, 2018. Participation was limited to audiologists who evaluate adult CI candidates, and respondents who do not provide adult CI care were excluded. Collected demographic information included work setting, years of experience, and highest level of education attained. Main Outcomes and Measures: Percentages, medians, and interquartile ranges were from aggregated responses concerning hearing aid verification methods; testing methods, materials, and practices; nonauditory factors that might affect CI candidacy; audiology practice patterns; and expanded indications for CIs. Results: Anonymized surveys were returned by 99 respondents; because surveys were available electronically, the number of audiologists who viewed the survey but did not respond was not available. Seven respondents identified themselves as pediatric specialists and were excluded, resulting in a total of 92 surveys available for analysis (denominators vary because respondents could complete the survey without answering all questions). Seventy percent of respondents (51 of 72) were doctors of audiology, and nearly 50% (33 of 74) were employed at universities and academic centers performing more than 50 CIs per year. When assessing adult candidacy for implant, most respondents reported using test materials from the Minimum Speech Test Battery: 96% (51 of 53), using AzBio sentences in quiet; 89% (47 of 53), AzBio sentences in noise; and 100% (53 of 53), the consonant-vowel nucleus-consonant, monosyllabic words test. However, these tests were applied inconsistently, with 39 of 53 respondents (74%) reporting use of a sound pressure level scale and the other 14 (26%) a hearing level scale at various decibel levels, and with some using a single signal-to-noise ratio and others using multiple ratios for sound-in-noise tests. Respondents' definitions of the best aided listening condition for assessing implant candidates also varied widely. Among the nonauditory factors ranked most important for assessing CI candidacy were patient's level of cognition and expectations of CI; yet, few respondents reported including cognitive or psychological tests in the assessment protocol. Conclusions and Relevance: Findings of this study reveal considerable variability in preoperative testing methods and practices across health care professionals assessing adult candidates for CI. This lack of standardization in the delivery of care may increase the risk for health care inequities, specifically in access to care for adults with clinically significant hearing loss.

Effect of age, electrode array, and time on cochlear implant impedances.

Objectives: To determine the impact of age, electrode array, and time on impedance patterns in cochlear implant (CI) patients. Methods: A retrospective case review was performed on 98 patients implanted with the CI24RE perimodiolar (PM) and CI422 lateral wall (LW) arrays between 2010 and 2014 to assess impedances at the 1 week and 3-6 month visit after initial stimulation (IS). Results: With respect to age, impedances were higher in young patients compared to older patients in the middle and apical turns. With time, there were significant reductions in impedances across most electrodes. Electrode array type also had a significant impact on impedance measurements with PM and LW arrays having higher impedances in the basal turn and apical turns, respectively. Furthermore, PM arrays demonstrated significantly lower impedances in the middle and apical turn with time, when compared to LW arrays. Conclusions: Age, electrode array, and time can independently affect CI impedances. Moreover, we show that PM arrays may be advantageous to LW arrays, due to demonstrated lower impedances in the middle and apical turns long term. Understanding the impact of impedance on speech discrimination and determining the intracochlear processes that contribute to differences in impedance are future research directions.

Multicenter US Clinical Trial With an Electric-Acoustic Stimulation (EAS) System in Adults: Final Outcomes.

OBJECTIVE: To demonstrate the safety and effectiveness of the MED-EL Electric-Acoustic Stimulation (EAS) System, for adults with residual low-frequency hearing and severe-to-profound hearing loss in the mid to high frequencies. STUDY DESIGN: Prospective, repeated measures. SETTING: Multicenter, hospital. PATIENTS: Seventy-three subjects implanted with PULSAR or SONATA cochlear implants with FLEX electrode arrays. INTERVENTION: Subjects were fit postoperatively with an audio processor, combining electric stimulation and acoustic amplification. MAIN OUTCOME MEASURES: Unaided thresholds were measured preoperatively and at 3, 6, and 12 months postactivation. Speech perception was assessed at these intervals using City University of New York sentences in noise and consonant-nucleus-consonant words in quiet. Subjective benefit was assessed at these intervals via the Abbreviated Profile of Hearing Aid Benefit and Hearing Device Satisfaction Scale questionnaires. RESULTS: Sixty-seven of 73 subjects (92%) completed outcome measures for all study intervals. Of those 67 subjects, 79% experienced less than a 30 dB HL low-frequency pure-tone average (250-1000 Hz) shift, and 97% were able to use the acoustic unit at 12 months postactivation. In the EAS condition, 94% of subjects performed similarly to or better than their preoperative performance on City University of New York sentences in noise at 12 months postactivation, with 85% demonstrating improvement. Ninety-seven percent of subjects performed similarly or better on consonant-nucleus-consonant words in quiet, with 84% demonstrating improvement. CONCLUSION: The MED-EL EAS System is a safe and effective treatment option for adults with normal hearing to moderate sensorineural hearing loss in the low frequencies and severe-to-profound sensorineural hearing loss in the high frequencies who do not benefit from traditional amplification.

Clinical, surgical, and electrical factors impacting residual hearing in cochlear implant surgery.

CONCLUSIONS: This study recommends using soft surgical principal and round window insertion to protect residual hearing with favorable anatomical exposure. Further studies are needed to evaluate the impact of the electrical stimulation on the organ of corti and hearing. OBJECTIVE: The objective of this study is to analyze various factors that impact on preservation of residual hearing post-implantation. METHODS: A retrospective study was performed to analyze loss of residual hearing in a cohort of 225 patients implanted in a large academic center. Sixty-four patients met the inclusion criteria. The impact of age at implantation, gender, etiology of hearing loss, cochleostomy vs round window insertion, partial vs full insertion, and effect of initial stimulation were analyzed using appropriate statistical analysis. RESULTS: The overall hearing preservation rate for all implanted patients was 64%. Loss of residual hearing was significantly more observed in cases of cochleostomy and/or non-soft surgical techniques. No correlation was observed with age at implantation, gender, side of implant, device manufacturer, and presence of pre-lingual deafness vs post-lingual, full or partial electrode insertion. In addition, there was a small but significant decrease in hearing between pre-stimulation and post-stimulation audiograms at 6000 Hz.

Temporal and spectral contributions to musical instrument identification and discrimination among cochlear implant users.

OBJECTIVE: To investigate the contributions of envelope and fine-structure to the perception of timbre by cochlear implant (CI) users as compared to normal hearing (NH) listeners. METHODS: This was a prospective cohort comparison study. Normal hearing and cochlear implant patients were tested. Three experiments were performed in sound field using musical notes altered to affect the characteristic pitch of an instrument and the acoustic envelope. Experiment 1 assessed the ability to identify the instrument playing each note, while experiments 2 and 3 assessed the ability to discriminate the different stimuli. RESULTS: Normal hearing subjects performed better than CI subjects in all instrument identification tasks, reaching statistical significance for 4 of 5 stimulus conditions. Within the CI population, acoustic envelope modifications did not significantly affect instrument identification or discrimination. With envelope and pitch cues removed, fine structure discrimination performance was similar between normal hearing and CI users for the majority of conditions, but some specific instrument comparisons were significantly more challenging for CI users. CONCLUSIONS: Cochlear implant users perform significantly worse than normal hearing listeners on tasks of instrument identification. However, cochlear implant listeners can discriminate differences in envelope and some fine structure components of musical instrument sounds as well as normal hearing listeners. The results indicated that certain fine structure cues are important for cochlear implant users to make discrimination judgments, and therefore may affect interpretation toward associating with a specific instrument for identification.

Differences in Perception of Musical Stimuli among Acoustic, Electric, and Combined Modality Listeners.

BACKGROUND: Cochlear implants have shown vast improvements in speech understanding for those with severe to profound hearing loss; however, music perception remains a challenge for electric hearing. It is unclear whether the difficulties arise from limitations of sound processing, the nature of a damaged auditory system, or a combination of both. PURPOSE: To examine music perception performance with different acoustic and electric hearing configurations. RESEARCH DESIGN: Chord discrimination and timbre perception were tested in subjects representing four daily-use listening configurations: unilateral cochlear implant (CI), contralateral bimodal (CIHA), bilateral hearing aid (HAHA) and normal-hearing (NH) listeners. A same-different task was used for discrimination of two chords played on piano. Timbre perception was assessed using a 10-instrument forced-choice identification task. STUDY SAMPLE: Fourteen adults were included in each group, none of whom were professional musicians. DATA COLLECTION AND ANALYSIS: The number of correct responses was divided by the total number of presentations to calculate scores in percent correct. Data analyses were performed with Kruskal-Wallis one-way analysis of variance and linear regression. RESULTS: Chord discrimination showed a narrow range of performance across groups, with mean scores ranging between 72.5% (CI) and 88.9% (NH). Significant differences were seen between the NH and all hearing-impaired groups. Both the HAHA and CIHA groups performed significantly better than the CI groups, and no significant differences were observed between the HAHA and CIHA groups. Timbre perception was significantly poorer for the hearing-impaired groups (mean scores ranged from 50.3-73.9%) compared to NH (95.2%). Significantly better performance was observed in the HAHA group as compared to both groups with electric hearing (CI and CIHA). There was no significant difference in performance between the CIHA and CI groups. Timbre perception was a significantly more difficult task than chord discrimination for both the CI and CIHA groups, yet the easier task for the NH group. A significant difference between the two tasks was not seen in the HAHA group. CONCLUSIONS: Having impaired hearing decreases performance compared to NH across both chord discrimination and timbre perception tasks. For chord discrimination, having acoustic hearing improved performance compared to electric hearing only. Timbre perception distinguished those with acoustic hearing from those with electric hearing. Those with bilateral acoustic hearing, even if damaged, performed significantly better on this task than those requiring electrical stimulation, which may indicate that CI sound processing fails to capture and deliver the necessary acoustic cues for timbre perception. Further analysis of timbre characteristics in electric hearing may contribute to advancements in programming strategies to obtain optimal hearing outcomes.

Ipsilateral acoustic electric pitch matching: a case study of cochlear implantation in an up-sloping hearing loss with preserved hearing across multiple frequencies.

OBJECTIVES: Determine ipsilateral acoustic electric pitch place match in a patient with preserved residual hearing across a broad frequency range. METHODS: Case report. Patient with up-sloping sensorineural hearing loss underwent implantation with a 680° insertion angle with preserved residual hearing. Pitch matching with variance of pulse rate was carried out. RESULTS: Electrical pitch percepts closely approximated the Greenwood map when compared to the acoustical pitch percepts and electrode position as determined by post-operative computed tomographic scan. The pitch matching results achieved from the deeply inserted electrodes, in the apical portion of the cochlea, suggest that the electrical stimulation may activate the dendritic extensions from the ganglion cell bodies that radiate from the terminal bulb. Stimulation rate influenced pitch perception in the apical turn but not in the mid- and basilar regions. DISCUSSION: Frequency to pitch allocation can potentially be improved by cochlear implants that access the apical third of the spiral ganglion. The ultimate goal of stimulating the apical third of the cochlea is to provide the maximum amount of spectral information to the user. We had the unique opportunity to work with a patient who presented with a severe sensorineural hearing loss rising to within normal limits and poor speech discrimination scores. Data from this study may aid our ability to give patients a broader spectrum of sound perception.