Performance Outcomes for Borderline Cochlear Implant Recipients With Substantial Preoperative Residual Hearing

Benefits and risks related to cochlear implantation for children with residual hearing: a systematic review

OBJECTIVE

This study aimed to synthesise information concerning the potential benefits and risks related to cochlear implants (CIs) versus hearing aids (HAs) in children with residual hearing.

DESIGN

A systematic review of articles published from January 2003 to January 2019 was conducted.

STUDY SAMPLE

Our review included studies that compared the benefits and risks of CIs versus HAs in children (≤18 years old) with residual hearing. A total of 3265 citations were identified; 8 studies met inclusion criteria.

RESULTS

Children with CIs showed significantly better speech perception scores post-CI than pre-CI. There was limited evidence related to improvement in everyday auditory performance, and the results showed non-significant improvement in speech intelligibility. One study on social-emotional functioning suggested benefits from CIs. In four studies, 37.2% (16/43) of children showed loss of residual hearing and 14.0% (8/57) had discontinued or limited use of their device.

CONCLUSIONS

Children with CIs showed improvement in speech perception outcomes compared to those with HAs. However, due to the limited number of studies and information to guide decision-making related to other areas of development, it will be important to conduct further research of both benefits and risks of CIs in this specific population to facilitate decision-making.

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 However, clinical practice is variable, with some providers using outdated criteria and others exceeding current labeled indications.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.

Electrically evoked compound action potentials in cochlear implant users with preoperative residual hearing

Introduction

Residual hearing in cochlear implant (CI) candidates requires the functional integrity of the nerve in particular regions of the cochlea. Nerve activity can be elicited as electrically evoked compound action potentials (ECAP) after cochlear implantation. We hypothesize that ECAP thresholds depend on preoperative residual hearing ability.

Materials and methods

In a retrospective study, we analyzed 84 adult cochlear implant users who had received a Nucleus® CI632 Slim Modiolar Electrode and who preoperatively had had residual hearing. Inclusion criteria were severe to profound hearing loss with preoperative measurable hearing in the ear to receive the implant, postlingual hearing loss, German as native language and correct placement of the electrode, inserted completely into the scala tympani. Electrically evoked compound action potential (ECAP) was recorded intraoperatively. The angular insertion was measured for each electrode contact from postoperative computed tomography to estimate the corresponding spiral ganglion frequency. Pure-tone audiometry and allocated ECAP thresholds were tested to investigate possible correlation.

Results

The average of hearing thresholds, tested at 0.5, 1, 2, and 4 kHz (4FPTA) was 82 ± 18 (range 47-129) dB HL. The success rate for recording ECAP thresholds was 96.9%. For all comparable pure-tone frequencies (1, 2, 4, and 8 kHz), there was significant correlation between preoperative hearing levels and intraoperative ECAP thresholds (p < 0.001). Higher hearing thresholds are associated with increased ECAP thresholds.

Conclusion

In CI candidates with adequate residual hearing, intraoperative electrophysiological measurement records lower thresholds. This outcome may be explained by the neural survival density of the peripheral system, with less neural degeneration.

Diagnostic value of preoperative measures in selecting post-lingually deafened candidates for cochlear implantation - a different approach

OBJECTIVES

We examined which preoperative diagnostic measure is most suited to serve as a selection criterion to determine adult cochlear implantation (CI) candidacy.

DESIGN

Preoperative diagnostic measures included pure tone audiometry (PTA; 0.5, 1, 2, 4 kHz), speech perception tests (SPT) unaided with headphones and with best-aided hearing aids (in quiet and in noise). Gain in speech perception was used as outcome measure. Performance of preoperative measures was analysed using the area under the curve (AUC) of receiver operating characteristic (ROC) curves.

STUDY SAMPLE

This retrospective longitudinal cohort study included 552 post-lingually deafened adults with CI in a tertiary referral centre in the Netherlands.

RESULTS

Best-aided SPT in quiet was the most accurate in defining which CI candidates improved their speech perception in quiet postoperatively. For an improvement in speech perception in noise, the best-aided SPT in noise was the most accurate in defining which adult would benefit from CI. PTA measures performed lower compared to the SPT measures.

CONCLUSIONS

SPT is better than PTA for selecting CI candidates who will benefit in terms of speech perception. Best-aided SPT in noise was the most accurate for indicating an improvement of speech perception in noise but was only evaluated in high performers with residual hearing. These insights will assist in formulating more effective selection criteria for CI.

Strategic perceptual weighting of acoustic cues for word stress in listeners with cochlear implants, acoustic hearing, or simulated bimodal hearing

Perception of word stress is an important aspect of recognizing speech, guiding the listener toward candidate words based on the perceived stress pattern. Cochlear implant (CI) signal processing is likely to disrupt some of the available cues for word stress, particularly vowel quality and pitch contour changes. In this study, we used a cue weighting paradigm to investigate differences in stress cue weighting patterns between participants listening with CIs and those with normal hearing (NH). We found that participants with CIs gave less weight to frequency-based pitch and vowel quality cues than NH listeners but compensated by upweighting vowel duration and intensity cues. Nonetheless, CI listeners' stress judgments were also significantly influenced by vowel quality and pitch, and they modulated their usage of these cues depending on the specific word pair in a manner similar to NH participants. In a series of separate online experiments with NH listeners, we simulated aspects of bimodal hearing by combining low-pass filtered speech with a vocoded signal. In these conditions, participants upweighted pitch and vowel quality cues relative to a fully vocoded control condition, suggesting that bimodal listening holds promise for restoring the stress cue weighting patterns exhibited by listeners with NH.

Individual Differences in Speech Recognition Changes After Cochlear Implantation

Importance

Cochlear implantation is highly effective at improving hearing outcomes, but results have been limited to groupwise analysis. That is, limited data are available for individual patients that report comparisons of preoperative aided speech recognition and postimplantation speech recognition.

Objective

To assess changes in preoperative aided vs postoperative speech recognition scores for individual patients receiving cochlear implants when considering the measurement error for each speech recognition test.

Design, Setting, and Participants

This cross-sectional study used a prospectively maintained database of patients who received cochlear implants between January 1, 2012, and December 31, 2017, at a tertiary, university-based referral center. Adults with bilateral sensorineural hearing loss undergoing cochlear implantation with 6- or 12-month postoperative measures using 1 or more speech recognition tests were studied.

Exposures

Cochlear implantation.

Main Outcomes and Measures

Postoperative word recognition (consonant-nucleus-consonant word test), sentence recognition (AzBio sentences in quiet), and sentence recognition in noise (AzBio sentences in +10-dB signal-to-noise ratio) scores, and association of each speech recognition score change with aided preoperative score to each test's measurement error.

Results

Analysis of data from a total of 470 implants from 323 patients included 253 male (53.8%) patients; the mean (SD) age was 61.2 (18.3) years. Most patients had statistically significant improvement in all speech recognition tests postoperatively beyond measurement error, including 262 (84.8%) for word recognition, 226 (87.6%) for sentence recognition, and 33 (78.6%) for sentence recognition in noise. A small number of patients had equivalent preoperative and postoperative scores, including 45 (14.5%) for word recognition, 28 (10.9%) for sentence recognition, and 9 (21.4%) for sentence recognition in noise. Four patients (1.6%) had significantly poorer scores in sentence recognition after implantation. The associations between age at implantation and change in speech recognition scores were -0.12 (95% CI, -0.23 to -0.01) for word recognition, -0.22 (95% CI, -0.34 to -0.10) for sentence recognition, and -0.10 (95% CI, -0.39 to 0.21) for sentence recognition in noise. Patients with no significant improvement were similarly distributed between all preoperative aided speech scores for word recognition (range, 0%-58%) and sentence recognition (range, 0%-56%) testing.

Conclusions and Relevance

In this cross-sectional study, with respect to preoperative aided speech recognition, postoperative cochlear implant outcomes for individual patients were largely encouraging. However, improvements in scores for individual patients remained highly variable, which may not be adequately represented in groupwise analyses and reporting of mean scores. Presenting individual patient data from a large sample of individuals with cochlear implants provides a better understanding of individual differences in speech recognition outcomes and contributes to more complete interpretations of successful outcomes after cochlear implantation.

[Neurophysiological parameters for speech recognition in patients with cochlear implants]

OBJECTIVES

 Cochlea Implants (CI) are the preferred treatment for deaf and highly hearing imparied people. While deaf people already profit enormously from any regained hearing perception, it is not as easy to predict a profitable outcome for people with a remaining sense of hearing. To provide patients the best possible outcome in speech understanding, a lot of parameters have to be identified and adjusted. The aim of this study is to show the influence of objective parameters on classified speech understanding using collected data.

MATERIAL AND METHODS

 A total of 52 patients and 65 ears aged between 18 and 80 years were included in this study. ECAP-thresholds from intraoperative measurements and impedance were used as objective parameters. T- and C/M-levels were defined as subjective parameters. To classify the performance the value of speech understanding was used.

RESULTS

 Differences between both groups (age, time after implantation) were not significant. The gained word scores at 500 Hz correlated significantly with the results of the speech perception threshold on two-digit numbers. The electrode impedances correlated on average with speech understanding with constant variability. The distributions of objective and subjective parameters showed partially significant differences. Many distributions showed significant differences to the normal distribution. Accordingly, the overlapping areas of the significance levels are very narrow.

CONCLUSION

 Higher impedances and incorrectly adjusted T-levels resulted in a worse speech understanding. Relation of C/M-levels to ECAP thresholds seem to be crucial for good speech understanding.

Clinical characteristics and outcomes of children with cochlear implants who had preoperative residual hearing

OBJECTIVE

Cochlear implants (CI) candidacy criteria have expanded to include children with more residual hearing. This study explored the clinical profiles and outcomes of children with CIs who had preoperative residual hearing in at least one ear.

DESIGN

A retrospective chart review was conducted to collect clinical characteristics and speech perception data. Pre- and post-CI auditory and speech perception data were analysed using a modified version of the Pediatric Ranked Order Speech Perception (PROSPER) score.

STUDY SAMPLE

This study included all children with residual hearing who received CIs in one Canadian paediatric centre from 1992 to 2018.

RESULTS

A total of 100 of 389 (25.7%) children with CIs had residual hearing (median 77.6 dB HL, better ear). The proportion of children with residual hearing increased from 1992 to 2018. Children who had auditory behaviour and speech perception tests (n = 83) showed higher modified PROSPER scores post-CI compared to pre-CI. Phonologically Balanced Kindergarten (PBK) test scores were available for 71 children post-CI; 81.7% (58/71) of children achieved > 80% on the PBK.

CONCLUSIONS

One in four children who received CIs had residual hearing, and most of them had severe hearing loss at pre-CI. These children showed a high level of speech perception with CIs.

Cochlear Implantation in Candidates With Moderate-to-Severe Hearing Loss and Poor Speech Perception

OBJECTIVES/HYPOTHESIS

To determine the improvement in word recognition score (WRS65 ) after cochlear implant (CI) surgery in hearing aid (HA) users with preoperative hearing threshold ≤80 dB HL and inadequate speech recognition scores with HA. Secondarily, to identify predictive factors for WRS65 with a CI (WRS65 [CI]) 6 months after surgery, derived from the standard German CI preoperative assessment.

STUDY DESIGN

Retrospective chart review.

METHODS

Retrospective review of all adult patients who received a Nucleus cochlear implant in the ear, nose, and throat department of the University Hospital of Erlangen between January 2010 and April 2019. The inclusion criteria were a preoperative hearing threshold ≤80 dB HL in the ear to receive the implantation, German as the native language, and at least 6 months postimplantation care at our center.

RESULTS

The inclusion criteria were met by 128 patients. All but two patients (98.4%) showed a significant improvement, WRS65 (CI) versus WRS65 with an (HA) (WRS65 [HA]), of at least 15 percentage points (pp). The median improvement was 55 pp with a median WRS65 (CI) of 70%. Three preoperative audiometric measures, the maximum word recognition score, age at implantation, and WRS65 (HA) were identified as predictive factors for WRS65 (CI). For three-quarters of the CI recipients, the score was not poorer than 12 pp below the predicted WRS65 (CI).

CONCLUSIONS

For patients with a hearing loss ≤80 dB HL, cochlear implantation should be considered when speech perception with an HA is insufficient. The prediction model can support counseling in this patient group.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E940-E945, 2021.

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.

Self-assessment of unilateral and bimodal cochlear implant experiences in daily life

Objective

The subjective experiences were assessed of cochlear implant (CI) users either wearing or not wearing a hearing aid (HA) at the contralateral ear.

Design

Unilateral CI-recipients were asked to fill out a set of daily-life questionnaires on bimodal HA use, hearing disability, hearing handicap and general quality of life.

Study sample

Twenty-six CI-recipients who regularly use a contralateral HA (bimodal group) and twenty-two CI-recipients who do not use a HA in the contralateral ear (unilateral group).

Results

Comparisons between both groups (bimodal versus unilateral) showed no difference in self-rated disability, hearing handicap or general quality of life. However within the group of bimodal listeners, participants did report a benefit of bimodal hearing ability in various daily life listening situations.

Conclusions

Bimodal benefit in daily life can consistently be experienced and reported within the group of bimodal users.

Selection Criteria for Cochlear Implantation in the United Kingdom and Flanders: Toward a Less Restrictive Standard

The impact of the newly introduced cochlear implantation criteria of the United Kingdom and Flanders (Dutch speaking part of Belgium) was examined in the patient population of a tertiary referral center in the Netherlands. We compared the patients who would be included/excluded under the new versus old criteria in relation to the actual improvement in speech understanding after implantation in our center. We also performed a sensitivity analysis to examine the effectiveness of the different preoperative assessment approaches used in the United Kingdom and Flanders.

The Benefits of Bimodal Aiding on Extended Dimensions of Speech Perception: Intelligibility, Listening Effort, and Sound Quality

The benefits of combining a cochlear implant (CI) and a hearing aid (HA) in opposite ears on speech perception were examined in 15 adult unilateral CI recipients who regularly use a contralateral HA. A within-subjects design was carried out to assess speech intelligibility testing, listening effort ratings, and a sound quality questionnaire for the conditions CI alone, CIHA together, and HA alone when applicable. The primary outcome of bimodal benefit, defined as the difference between CIHA and CI, was statistically significant for speech intelligibility in quiet as well as for intelligibility in noise across tested spatial conditions. A reduction in effort on top of intelligibility at the highest tested signal-to-noise ratio was found. Moreover, the bimodal listening situation was rated to sound more voluminous, less tinny, and less unpleasant than CI alone. Listening effort and sound quality emerged as feasible and relevant measures to demonstrate bimodal benefit across a clinically representative range of bimodal users. These extended dimensions of speech perception can shed more light on the array of benefits provided by complementing a CI with a contralateral HA.

Bimodal Hearing Aid Retention after Unilateral Cochlear Implantation

The goal of this study was to investigate contralateral hearing aid (HA) use after unilateral cochlear implantation and to identify factors of influence on the occurrence of a unilateral cochlear implant (CI) recipient becoming a bimodal user. A retrospective cross-sectional chart review was carried out among 77 adult unilateral CI recipients 1 year after implantation. A bimodal HA retention rate of 64% was observed. Associations with demographics, hearing history, residual hearing and speech recognition ability were investigated. Better pure-tone thresholds and unaided speech scores in the non-implanted ear, as well as a smaller difference in speech recognition scores between both ears, were significantly associated with HA retention. A combined model of HA retention was proposed, and cut-off points were determined to identify those CI recipients who were most likely to become bimodal users. These results can provide input to clinical guidelines concerning bimodal CI candidacy.