Marcia C. Adunka

Hearing-in-noise benefits after bilateral simultaneous cochlear implantation continue to improve 4 years after implantation.

Objective: The purpose of this 4-year longitudinal study was to assess the stability of the binaural benefits of head shadow, summation, and squelch for bilateral cochlear implant recipients and to quantify these benefits for the understanding of speech in noise. Design: This is a prospective study of 9 patients who received simultaneous bilateral insertion of MED-EL COMBI +40 cochlear implants in a single-stage operation at the University of North Carolina, Chapel Hill, NC. Each patient had postlingual deafness of short duration before insertion of the device. Each year, the patients were tested for word recognition using consonant-nucleus-consonant words in quiet and speech perception in noise using City University of New York sentences. These tests were administered using direct audio input to the implants. Head-related transfer functions were used to simulate speech in noise testing in a spatial environment. Speech was always presented at midline (0°), and the noise masker was presented at either side or midline (−90, 0, +90 degrees). Results: The binaural benefits of head shadow and summation effects developed early in the postoperative period and remained stable throughout the follow-up period. Squelch developed more slowly and was first demonstrated at 12 months after implantation but continued to increase beyond the first year of follow-up. Conclusion: Benefits of head shadow and summation emerge early and remain stable. However, squelch has the most protracted period of development, with increasing benefit after a year or more of implant experience. These data support the idea that binaural integration continues several years after insertion of bilateral cochlear implant devices.

Influence of cochlear implant insertion depth on performance: a prospective randomized trial.

Objective The purpose of the present study was to assess the influence of electrode insertion length on cochlear implant (CI) performance. Study Design Prospective randomized allocation of CI patients to receive either a standard (26.4 mm)- or medium (20.9 mm)-length electrode array. The processing strategy and electrode insertion number were held constant. The postoperative testing audiologist was blinded to the map details and array. Setting Tertiary referral center. Patients Thirteen adult CI candidates randomized to receive the standard- (n = 7) or medium-length (n = 6) electrode array. Intervention(s) Unilateral CI using standard- or medium-length array from the same implant system. Main Outcome Measures(s) Speech perception was assessed with HINT sentences in quiet and steady-state noise (SNR, +10) and CNC words in quiet at defined intervals. Quality of life was assessed using the Hearing Device Satisfaction Survey and the Abbreviated Profile of Hearing Aid Benefit (APHAB). Music perception was assessed using the Musical Sounds In Cochlear implants (MuSIC) test. Postoperative electrode insertion angle was assessed using reconstructed computed tomographic images. Results Interim analysis necessitated discontinuation of subject enrollment by the institutional review board. There was a trend (p = 0.07) for improved speech perception performance among standard array patients. This difference was significant when the standard array group was increased retrospectively. Quality of life and music perception differences were not apparent between groups. Conclusion Longer electrode insertions (and greater insertion angles) appear to offer better speech perception performance in the early postactivation period when using the same implant system.

Hearing preservation and speech perception outcomes with electric‐acoustic stimulation after 12 months of listening experience

To report on single‐center data of an FDA‐approved clinical trial on the objective benefits of cochlear implantation and subsequent ipsilateral Electric‐Acoustic Stimulation (EAS).

Cochleostomy Versus Round Window Insertions: Influence on Functional Outcomes in Electric-acoustic Stimulation of the Auditory System

Objective To assess the potential influence of 2 different surgical access routes to scala tympani for hearing preservation cochlear implantation on outcomes. Study Design Retrospective review. Setting Tertiary care academic center. Patients Twenty adult subjects participating in a prospective clinical trial on electric-acoustic stimulation. Subjects underwent cochlear implantation with attempted hearing preservation and subsequent ipsilateral electric-acoustic stimulation of the auditory system. Interventions Eight subjects (40%) were implanted using a round window–related cochleostomy and 12 subjects (60%) via a round window approach. Main Outcome Measures Postoperative acoustic hearing preservation and speech perception measures were obtained at defined intervals and compared for both groups with and without the use of the external speech processor. Results The data demonstrate no statistically significant differences in postoperative outcomes for both preservation of residual hearing and unaided and aided speech perception between the cochleostomy and round window groups. Conclusion The results of this investigation suggest that hearing preservation cochlear implantation can be performed either via a round window–related cochleostomy as well as via the round window membrane itself with similar outcomes in terms of both hearing preservation rates as well as speech perception measures.

Long-term Speech Perception in Elderly Cochlear Implant Users

IMPORTANCE A review of a test battery presented in both quiet and noise may clarify what the progression of speech perception abilities is in older adult cochlear implant users and whether the performance declines with advancing age. OBJECTIVE To examine whether older adults (≥65 years) with cochlear implants maintain stable speech perception performance after at least 10 years of listening experience with an external speech processor. DESIGN AND SETTING Retrospective analysis performed in an academic tertiary care center. PARTICIPANTS Fourteen older adult cochlear implant recipients with at least 10 years of listening experience. MAIN OUTCOME MEASURES Speech perception outcomes as measured with Consonant-Nucleus-Consonant words in quiet and Hearing in Noise Test sentences in quiet and steady-state noise were analyzed retrospectively at the 6-month and 1-, 5-, and 10-year postoperative follow-up intervals. RESULTS Consonant-Nucleus-Consonant word scores remained stable between 6 months and 1 year of listening experience, improved significantly (P < .001) between 1 year and 5 years, and remained stable between 5 years and 10 years. Hearing in Noise Test sentence scores in quiet and noise showed a similar pattern, with stability in performance between the 6-month to 1-year and 5-year to 10-year follow-up intervals, and significantly improved performance (P = .04) between the 1-year and 5-year follow-up intervals. CONCLUSIONS AND RELEVANCE On average, patients who undergo cochlear implantation at age 65 years or older do not experience a decline in speech perception performance with extended listening experience and may potentially continue to see improvements beyond the 1-year follow-up interval.

Is electric acoustic stimulation better than conventional cochlear implantation for speech perception in quiet

Objective: To assess whether combined electric acoustic stimulation (EAS) provides a significant hearing-in-quiet advantage over ipsilateral electrical stimulation alone, ipsilateral acoustic stimulation alone, or full-length cochlear implantation without preserved hearing. Setting: Tertiary care academic referral center. Patients: Two matched groups of cochlear implant (CI) patients that were implanted with either an EAS or full-length device and use similar speech processing strategies. Intervention: EAS cochlear implantation and hearing preservation (n = 10, EAS group) or conventional CI (n = 10, conventional CI group) without hearing preservation. Main Outcome Measures: Status of residual hearing and speech perception data in quiet at 3 and 6 months after fitting. Results: Preoperatively, the mean aided Consonant Nucleus Consonant Word Test word score was 24.2 ± 8.3% for the EAS group and 20.7 ± 11.36% for the conventional CI group (p = 0.14). In the conventional CI group, hearing was not preserved after surgery in any subject, whereas 9 of the 10 subjects in the EAS group had hearing preservation. Mean CNC word scores at 6 months after activation using electrical stimulation alone were 50.3 ± 11.53% in the EAS group and 53.8 ± 17.32% in the conventional CI group (p = 0.81). Between-condition comparisons among the EAS subjects revealed that combined stimulation was significantly better than either the electrical or acoustic stimulation condition alone (p < 0.05). When compared with the conventional CI group, combined stimulation in EAS subjects was again superior (p < 0.05). Conclusion: Limited length CI with ipsilateral hearing preservation provides comparable speech perception performance results to conventional CI when electric stimulation alone is used. The addition of ipsilateral acoustic stimulation in ears with preserved residual hearing provides an additional benefit over electrical stimulation alone.

Influence of Age at Revision Cochlear Implantation on Speech Perception Outcomes

IMPORTANCE This study reviewed whether advanced age should be a consideration when revision cochlear implantation is warranted. OBJECTIVE To examine whether age at revision cochlear implantation is related to postrevision speech perception performance. DESIGN, SETTING, AND PARTICIPANTS A retrospective analysis was performed in an academic tertiary care center. Participants included 14 younger adults (<65 years) and 15 older adults (≥65 years) who underwent revision cochlear implantation. INTERVENTION Revision cochlear implantation. MAIN OUTCOMES AND MEASURES Speech perception performance, as measured with consonant-nucleus-consonant [CNC] words in quiet, at the best prerevision interval as well as the 3- and 6-month postrevision intervals were compared between the 2 cohorts. The CNC word test consists of 10 lists of 50 phonemically balanced monosyllabic words, scored with a range of 0% to 100% correct. RESULTS Both cohorts experienced a restoration in speech perception scores after revision cochlear implantation compared with their best performance before the revision (mean [SD] CNC word test scores for the younger cohort: 43.9% [25.6%] before revision and 47.7% [21.3%] at 3 months and 47.6% [19.8%] at 6 months after revision; for the older cohort: 36.3% [19.1%] before revision and 35.3% [17.2%] at 3 months and 39.9% [16.3%] at 6 months after revision; F₂,₅₄= 0.93; P = .40). There was no interaction between age at revision surgery and speech perception performance at each assessment interval (F₂,₅₄= 0.51; P = .60). CONCLUSIONS AND RELEVANCE In this study, age at revision cochlear implantation was not related to postrevision speech perception performance. Advanced age should not be considered a contraindication to revision cochlear implantation.

Impact of Electric Stimulation on Residual Hearing.

BACKGROUND Candidacy criteria for cochlear implantation are expanding to include patients with substantial low-to-mid frequency hearing sensitivity. Postoperative hearing preservation has been achieved in cochlear implant recipients, though with variable outcomes. Previous investigations on postoperative hearing preservation outcomes have evaluated intraoperative procedures. There has been limited review as to whether electric stimulation influences hearing preservation. PURPOSE The purpose of this analysis was to evaluate whether charge levels associated with electric stimulation influence postoperative hearing preservation within the first year of listening experience. RESEARCH DESIGN Retrospective analysis of unaided residual hearing and charge levels. STUDY SAMPLE Twenty-eight cochlear implant recipients with postoperative residual hearing in the operative ear and at least 12 mo of listening experience with electric-acoustic stimulation (EAS). DATA COLLECTION AND ANALYSIS Assessment intervals included initial cochlear implant activation, initial EAS activation, and 3-, 6-, and 12-mo postinitial EAS activation. A masked low-frequency bone-conduction (BC) pure-tone average (PTA) was calculated for all participants at each assessment interval. Charge levels for each electrode were determined using the most comfortable loudness level and pulse width values. Charge levels associated with different regions of the electrode array were compared to the change in the low-frequency BC PTA between two consecutive intervals. RESULTS Charge levels had little to no association with the postoperative change in low-frequency BC PTA within the first year of listening experience. CONCLUSIONS Electric charge levels do not appear to be reliably related to the subsequent loss of residual low-frequency hearing in the implanted ear within the first year of EAS listening experience.

Round window stimulation for conductive and mixed hearing loss

Objective Assess surgical complications, postoperative residual hearing, and speech perception outcomes of placement of a middle ear implant on the round window in conductive and mixed hearing loss cases. Study Design Single-subject, repeated-measures design where each subject served as his or her own control. Setting Tertiary referral medical systems. Subjects Eighteen subjects with either conductive or mixed hearing loss who could not benefit from conventional amplification were enrolled in a clinical trial investigating vibratory stimulation of the round window. Intervention The floating mass transducer (FMT) was positioned in the round window niche. Main Outcome Measures Unaided residual hearing, and aided sound field thresholds and speech perception abilities were evaluated preoperatively, and at 1, 3, 6, and 10 months post-activation of the external speech processor. Results Six subjects experienced complications that either required further medical management or resolved on their own. There was no difference in residual bone conduction thresholds or unaided word discrimination over time. All subjects experienced a significant improvement in aided speech perception abilities as compared to preoperative performance. Conclusion Subjects with conductive and mixed hearing loss with placement of the FMT in the round window niche experienced improved sound field thresholds and speech perception, without compromising residual hearing thresholds. Vibratory stimulation of the round window via a middle ear implant may be an appropriate treatment option for patients with conductive and mixed hearing loss. Additional research is needed on the preferred placement of the FMT, improvement of functional gain, and methods to limit postoperative complications and need for revision surgery.

Comparison of two cochlear implant coding strategies on speech perception

Objective: Assess whether differences in speech perception are observed after exclusive listening experience with high-definition continuous interleaved sampling (HDCIS) versus fine structure processing (FSP) coding strategies. Methods: Subjects were randomly assigned at initial activation of the external speech processor to receive the HDCIS or FSP coding strategy. Frequency filter assignments were consistent across subjects. The speech perception test battery included CNC words in quiet, HINT sentences in quiet and steady noise (+10 dB SNR), AzBio sentences in quiet and a 10-talker babble (+10 dB SNR), and BKB-SIN. Assessment intervals included 1, 3, and 6 months post-activation. Results: Data from 22 subjects (11 with HDCIS and 11 with FSP) were assessed over time. Speech perception performance was not significantly different between groups. Discussion: Speech perception performance was not significantly different after 6 months of listening experience with the HDCIS or FSP coding strategy.