Adult Cochlear Implant Research Articles

Binaural Integration of Spectrally Degraded Speech in Adult Cochlear Implant Recipients with Single-Sided Deafness

Introduction: Our purpose was to investigate binaural integration for spectrally degraded speech in normal-hearing (NH) subjects, single-sided deafness (SSD) cochlear implant (CI) recipients, and bilateral deaf bilateral CI recipients. Methods: We tested ten adult subjects in each group with a modified version of the binaural fusion test according to Matzker. Speech recognition was assessed for monotic listening with the better-hearing ear or CI, monotic listening with the poorer-hearing ear or CI, and dichotic listening. We employed two presentation modes: (1) low pass (LP)-filtered speech to the better ear or CI and high pass (HP)-filtered speech to the poorer ear or CI, and (2) LP-filtered speech to the poorer ear or CI and HP-filtered speech to the better ear or CI. Five magnitudes of LP and HP filtering, i.e., spectral degradation, for each presentation mode were applied yielding two spectrally overlapping and three nonoverlapping presentation conditions. Sentences from the Oldenburg Children’s sentence test were applied to assess speech recognition. Results: NH subjects, SSD CI recipients, and bilateral CI recipients were able to understand spectrally degraded speech under both monotic and dichotic listening conditions for both the presentation modes. Speech performance decreased with the increasing loss of spectral information in all the three subject groups. In the NH subjects, speech recognition scores significantly improved for dichotic compared with each monotic listening type under two spectrally nonoverlapping conditions. The SSD CI subjects showed a significant improvement in speech scores for dichotic listening compared with monotic listening with the NH ear under one nonoverlapping condition, i.e., a dichotic benefit in speech recognition with CI. We saw a dichotic benefit in the bilateral CI recipients who achieved significantly better speech scores for dichotic compared with monotic listening with the better CI in three nonoverlapping conditions. Conclusions: All the three groups (NH subjects, SSD CI recipients, and BiCI recipients) showed binaural integration for the side-separated presentation of spectrally degraded speech. Use of strictly side-separated dichotic stimulus presentation avoided the possible occurrence of physical effects such as the head shadow effect and therefore, confirmed the binaural benefit attributable to central binaural processing.

Normative Cochlear Implant Quality of Life (CIQOL)-35 Profile and CIQOL-10 Global Scores for Experienced Cochlear Implant Users from a Multi-Institutional Study.

Although adult cochlear implant (CI) outcomes have primarily focused on speech recognition scores, the rigorous development of a CI-specific patient-reported outcome measure provides an opportunity for a more comprehensive and ecologically valid approach to measure the real-world functional abilities of adult CI users. Here, we report for the first time normative Cochlear Implant Quality of Life (CIQOL)-35 Profile and global scores and variance for a large, multi-institutional sample of adult CI users. Cross-sectional study design. CI centers in the United States. Seven hundred five adults with bilateral moderate to profound hearing loss with at least 1 year of CI use. Cochlear implantation. CIQOL-35 Profile and CIQOL-10 Global scores. During the development of the CIQOL instruments, 1,000 CI users from all regions of the United States were invited to participate in studies. Of these, 705 (70.5%) completed all portions of the study, and their data are reported here. Mean CIQOL domain scores were highest (indicating better function) for the emotional and social domains and lowest for listening effort. The entertainment and social domains demonstrated the widest distribution of scores and largest standard deviations, indicating greatest variability in function. Overall, there were minimal ceiling and floor effects for all domains. Normative scores from a large sample of experienced adult CI users are consistent with clinical observations, showing large differences in functional abilities and large variability. Normative CIQOL data for adult CI users have the potential to enhance preoperative discussions with CI candidates, improve post-CI activation monitoring, and establish standards for CI centers.

Knowledge of and Attitudes Toward Hearing Loss, Hearing Aids, and Cochlear Implants in Adults

Purpose: This study investigates the knowledge of and attitudes toward hearing loss and hearing aids (HA) and cochlear implants (CI) based on background. Methods: A total of 356 adults, including users of HA and CI participated with a variety of background variables, including age, use of amplification, experience with hearing-impaired listeners, and educational majors in audiology and speech-language pathology. The group completed 10 questions on their knowledge of and attitudes toward hearing loss, HA and CI. Results: Almost all the participants understood HA and CI, but HA and CI users had a low level of knowledge of hearing loss, HA and CI. Participants had positive attitudes toward HA and CI. However, HA and CI current users were mystified by their hearing devices. They had no negative attitudes toward hearing devices that is worn by people with hearing loss, but non-users felt uncomfortable if others noticed they were using HA and CI. Students with audiology and speech-language pathology majors showed greater knowledge and more positive attitudes toward hearing loss and HA and CI. Conclusion: Despite most participants having a good knowledge of hearing loss, current device users had a rather low level of knowledge about hearing loss and their devices. These results indicate that users need more education about hearing loss and their own devices. Further, some non-users felt a stigma toward the use of HA and CI. These results suggest that more education is needed for better knowledge and more positive attitudes toward hearing loss and both HA and CI.

Adult Cochlear Implantation Under Local Anesthesia and Conscious Sedation with Dexmedetomidine: Efficacy and a Method to Interact with the Conscious and Cooperative Patient.

Background:This study describes the efficacy of cochlear implantation under local anesthesia with conscious sedation with dexmedetomidine in adult patients and proposes a method to communicate with the conscious and cooperative patient intraoperatively. This less invasive anesthetic procedure is suitable for patients with comorbidities preventing general anesthesia.Methods:Unilateral cochlear implantation with Oticon Medical systems was performed in 10 adult patients with comorbidities preventing general anesthesia. Classical cochlear implantation was performed under local anesthesia and conscious sedation with dexmedetomidine. Cue cards were used to support intraoperative dialogue. Outcome measures were intraoperative adverse events, patient perceptions, as well as postoperative completions measured with a questionnaire.Results:The procedure was successful for all 10 patients. Dexmedetomidine lead to rapid and successful conscious sedation and no case of high blood pressure or aggravation of comorbidities was noted. Stapedial reflex measurements led to reliable thresholds. The usage of the cue cards was successful: patients were able to read the cue cards and thereby the medical team could inform the patients of surgical progress and ask the patients questions.Conclusion:Cochlear implantation and intraoperative dialogue with the conscious and cooperative patient is possible. The main advantage of the anesthetic procedure is the reduction in intra- and postoperative complications. Further, expected benefits include a less invasive procedure, the conscious state of the patient which enables the recording of auditory perception, and the absence of nonauditory percepts such as facial nerve stimulation during implant stimulation, a shorter surgical duration, and lower-associated costs.

Adult Cochlear Implantation Under Local Anesthesia and Conscious Sedation with Dexmedetomidine: Efficacy and a Method to Interact with the Conscious and Cooperative Patient.

This study describes the efficacy of cochlear implantation under local anesthesia with conscious sedation with dexmedetomi- dine in adult patients and proposes a method to communicate with the conscious and cooperative patient intraoperatively. This less invasive anesthetic procedure is suitable for patients with comorbidities preventing general anesthesia. Unilateral cochlear implantation with Oticon Medical systems was performed in 10 adult patients with comorbidities preventing general anesthesia. Classical cochlear implantation was performed under local anesthesia and conscious sedation with dexmedetomidine. Cue cards were used to support intraoperative dialogue. Outcome measures were intraoperative adverse events, patient perceptions, as well as post- operative completions measured with a questionnaire. The procedure was successful for all 10 patients. Dexmedetomidine lead to rapid and successful conscious sedation and no case of high blood pressure or aggravation of comorbidities was noted. Stapedial reflex measurements led to reliable thresholds. The usage of the cue cards was successful: patients were able to read the cue cards and thereby the medical team could inform the patients of surgical progress and ask the patients questions. Cochlear implantation and intraoperative dialogue with the conscious and cooperative patient is possible. The main advantage of the anesthetic procedure is the reduction in intra- and postoperative complications. Further, expected benefits include a less invasive procedure, the conscious state of the patient which enables the recording of auditory perception, and the absence of nonauditory percepts such as facial nerve stimulation during implant stimulation, a shorter surgical duration, and lower-associated costs.

Remote Monitoring of Adult Cochlear Implant Recipients Using Digits-in-Noise Self-Testing.

The COVID-19 pandemic has accelerated the uptake and scope of telehealth. This study determined the accuracy and reliability of a smartphone digits-in-noise (DIN) test when conducted by adult cochlear implant (CI) recipients in a simulated home environment compared with a clinic setup. Perceptions of remote monitoring using speech-in-noise (SIN) testing were also explored. Thirty-three adult CI recipients between 18 and 78 years of age (M = 46.7, SD = ±20.4) conducted the DIN test in a simulated home environment and a clinic setup. Test-retest reliability across the two environments and comparisons between test settings were evaluated. A survey explored the perceptions of adult CI recipients regarding remote monitoring and use of the DIN self-test. Mean-aided speech reception thresholds (SRTs) in the clinic and simulated home environment test conditions and clinic and simulated home environment retest conditions did not differ significantly. Mean test-retest SRTs in the clinic and simulated home environment were significantly different (p < .05). High intraclass correlation coefficient and low standard error of measurement scores reflected good and excellent reliability between test-retest measures and between clinic and simulated home environment measures. Most participants were positive about the possibility of using the DIN test at home to self-assess speech perception, although some test adjustments such as including training items and a less adverse starting signal-to-noise ratio may be required. Adult CI recipients can use the smartphone DIN test to self-assess aided SIN performance in a home environment with accuracy and reliability relatively similar to clinic testing. https://doi.org/10.23641/asha.20044418.

Lateralization Pattern of the Weber Tuning Fork Test in Longstanding Unilateral Profound Hearing Loss: Implications for Cochlear Implantation.

The Weber tuning fork test is a standard otologic examination tool in patients with unilateral hearing loss. Sound should typically lateralize to the contralateral side in unilateral sensorineural hearing loss. The observation that the Weber test does not lateralize in some patients with longstanding unilateral deafness has been previously described but remains poorly understood. In the present study, we conducted a retrospective analysis of the medical records of patients with unilateral profound hearing loss (single-sided deafness or asymmetric hearing loss) for at least ten years. In this patient cohort, childhood-onset unilateral profound hearing loss was significantly associated with the lack of lateralization of the Weber tuning fork test (Fisher’s exact test, p < 0.05) and the absence of tinnitus in the affected ear (Fisher’s exact test, p < 0.001). The findings may imply a central adaptation process due to chronic unilateral auditory deprivation starting before the critical period of auditory maturation. This notion may partially explain the poor outcome of adult cochlear implantation in longstanding single-sided deafness. The findings may suggest a role for the Weber test as a simple, quick, and economical tool for screening poor cochlear implant candidates, thus potentially supporting the decision-making and counseling of patients with longstanding single-sided deafness.

Cochlear Implantation Improves Both Speech Perception and Patient-Reported Outcomes: A Prospective Follow-Up Study of Treatment Benefits among Adult Cochlear Implant Recipients.

Cochlear implantation is considered the best treatment option for patients with severe-to-profound sensorineural hearing loss for whom conventional hearing aids are insufficient. We used a repeated measures longitudinal approach to evaluate speech recognition and patient-reported outcomes after cochlear implantation in an unbiased cohort of Danish adult patients in a prospective cohort study. We assessed 39 recipients before and two times after implantation using a battery of tests that included Dantale I, the Danish Hearing in Noise Test, the Nijmegen Cochlear Implant Questionnaire, and the Speech, Spatial, and Qualities of Hearing Scale. The study group improved significantly on all outcome measures following implantation. On average, Dantale I scores improved by 29 percentage points and Hearing in Noise Test scores improved by 22 percentage points. Most notably, the average Dantale score improved from 26 to 70% in the CI in quiet condition and from 12 to 42% in the cochlear implantation in noise condition when tested monaurally. Dantale demonstrated a significant positive correlation with Nijmegen Cochlear Implant Questionnaire and Speech, Spatial, and Qualities of Hearing Scale scores, while Hearing in Noise Test had no significant correlation with the patient-reported outcome measures. Patients improved significantly at 4 months and marginally improved further at 14 months, indicating that they were approaching a plateau. Our study’s use of audiometric and patient-reported outcome measures provides evidence of the treatment benefits of cochlear implantation in adults, which may help physicians advise patients on treatment decisions and align treatment benefit expectations, as well as serve as a foundation for the development of new cochlear implantation selection criteria.

Preoperative Visual Measures of Verbal Learning and Memory and their Relations to Speech Recognition After Cochlear Implantation.

This study examined the performance of a group of adult cochlear implant (CI) candidates (CIC) on visual tasks of verbal learning and memory. Preoperative verbal learning and memory abilities of the CIC group were compared with a group of older normal-hearing (ONH) control participants. Relations between preoperative verbal learning and memory measures and speech recognition outcomes after 6 mo of CI use were also investigated for a subgroup of the CICs. A group of 80 older adult participants completed a visually presented multitrial free recall task. Measures of word recall, repetition learning, and the use of self-generated organizational strategies were collected from a group of 49 CICs, before cochlear implantation, and a group of 31 ONH controls. Speech recognition outcomes were also collected from a subgroup of 32 of the CIC participants who returned for testing 6 mo after CI activation. CICs demonstrated poorer verbal learning performance compared with the group of ONH control participants. Among the preoperative verbal learning and memory measures, repetition learning slope and measures of self-generated organizational clustering strategies were the strongest predictors of post-CI speech recognition outcomes. Older adult CI candidates present with verbal learning and memory deficits compared with older adults without hearing loss, even on visual tasks that are independent from the direct effects of audibility. Preoperative verbal learning and memory processes reflecting repetition learning and self-generated organizational strategies in free recall were associated with speech recognition outcomes 6 months after implantation. The pattern of results suggests that visual measures of verbal learning may be a useful predictor of outcomes in postlingual adult CICs.

Changes in cognitive performance after cochlear implantation in adults and older adults: a systematic review and meta-analysis

Objectives To conduct critical assessment of the literature on the effects of cochlear implantation on adults’ cognitive abilities. Design PubMed, Scopus, Lilacs, Web of Science, Livivo, Cochrane, Embase, PsycInfo, and grey literature were searched. Eligibility criteria: age 18 or over with severe-to-profound bilateral hearing loss, cochlear implantation, cognitive test before and after implantation. Risk of bias was assessed using ROB, ROBINS-I and MASTARI tools. Meta-analysis was performed. Study sample Out of 1830 studies, 16 met the inclusion criteria. Results On AlaCog test, significant improvement was found after implantation [MD = −46.64; CI95% = −69.96 to −23.33; I 2 = 71%]. No significant differences were found on the Flanker, Recall, Trail A and n-back tests (p > 0.05). For MMSE, no significance was found [MD 0.63; CI 95% = −2.19 to 3.45; I 2 = 88%]. On TMT, an overall significant effect with a 9-second decrease in processing speed post-implantation [MD = −9.43; CI95% = −15.42 to −3.44; I 2 = 0%]. Conclusion Cognitive improvements after cochlear implantation may depend on time and the cognitive task evaluated. Well-designed studies with longer follow-up are necessary to examine whether cochlear implantation has a positive influence on cognitive abilities. Development of cognitive assessment tools to hearing-impaired individuals is needed.

Cortical Auditory Evoked Potentials Recorded Directly Through the Cochlear Implant in Cochlear Implant Recipients: a Feasibility Study.

The use of objective measures in cochlear implant (CI) mapping, has greatly contributed to the refinement of the setting of audible and comfortable stimulation levels, which serve as the basis of the mapping process, especially in cases of infants and young children. In addition, objective measures can also confirm the integrity of the CI system. Current CI objective measures mainly reflect neural activity from the auditory nerve and brainstem site. An objective cortical CI measure that reflects directly central auditory activity is greatly needed, especially since it is closely related to CI outcomes in both children and adults. Recording the brain activity currently requires an external evoked potential (EP) system including scalp electrodes, rendering it impractical for widespread clinical use. This study aimed to assess the feasibility of recording cortical auditory evoked potentials (CAEPs) directly and solely through the cochlear implant in response to external acoustic stimulation in the non-implanted ear. A total of nine CI users (four females and five males) participated, including seven post-lingual adults (23 to 72 years), and two pediatric cases, one teenager (15 years), and one child (8 years)-both pre-lingual. All participants had a residual hearing in the ear contralateral to the ear with CI. CAEPs were recorded in the implanted ear in response to acoustic stimulation of the non-implanted ear, consisting of a brief tonal stimulus at comfortable listening levels. Recordings used an intracranial montage consisting of an intracochlear apical electrode (active) and one of the two ( case and ring ) extra-cochlear implanted electrodes serving as reference electrodes. The CI CAEPs were compared with a single-channel conventional CAEP recording obtained simultaneously via scalp electrodes (Fz-mastoid) using a standard EP system and an external trigger from the CI system. Statistical comparisons were made between the CI and the scalp recorded CAEPs and for differences between the CI CAEP measures acquired using the ring and the case as the reference electrode. CAEPs recorded directly and solely through the CI were equivalent to the standard scalp recorded CAEP responses. CAEP responses acquired using the case electrode as the reference were highly correlated in terms of morphology, latencies, and amplitudes of the CAEP components. The CI CAEP latencies of the two pediatric cases were consistent with their normal developed age group and delayed relative to adult CAEP latencies, as expected. This study demonstrated the feasibility of recording long latency CAEPs directly and solely through CI in adults with residual hearing, in response to acoustic stimulation of the non-implanted ear. The CI CAEPs closely resembled the CAEPs recorded simultaneously by an external EP system and via scalp electrodes. The ability to record directly from the implant, without the need of an external recording system, presents an innovative method with many clinical and research implications.

Cochlear Implantation in Adults With Single-Sided Deafness: A Systematic Review and Meta-analysis.

To determine the clinical outcomes of adult patients with single-sided deafness (SSD) undergoing ipsilateral cochlear implantation. An electronic search of Medline and Embase articles. A systematic review was performed with a search strategy developed by a licensed librarian to identify studies of adult patients with SSD who underwent ipsilateral cochlear implantation. Articles were managed in Covidence and evaluated by 2 independent reviewers. Risk of bias was assessed and data were extracted, including patient demographics, etiology of deafness, duration of deafness, and postoperative change in speech recognition, tinnitus, sound localization, and quality of life (QoL). A meta-analysis was performed, and pooled mean differences were calculated for each outcome of interest via random effects models by each outcome, as well as subgroup analyses by the individual clinical score used. Of 2309 studies identified, 185 full texts were evaluated, and 50 were ultimately included involving 674 patients. Speech perception scores in quiet and noise, tinnitus control, sound localization, and QoL all significantly improved after implantation. Pooled outcomes demonstrated score improvements in speech perception (standardized mean difference [SMD], 2.8 [95% CI, 2.16-3.43]), QoL (SMD, 0.68 [95% CI, 0.45-0.91]), sound localization (SMD, -1.13 [95% CI, -1.68 to -0.57]), and tinnitus score reduction (SMD, -1.32 [95% CI, -1.85 to -0.80]). Cochlear implantation in adults with SSD results in significant improvements in speech perception, tinnitus control, sound localization, and QoL.

Personal Characteristics Associated with Ecological Momentary Assessment Compliance in Adult Cochlear Implant Candidates and Users.

Ecological momentary assessment (EMA) often places high physical and mental burden on research participants compared with retrospective self-reports. The high burden could result in noncompliance with the EMA sampling scheme protocol. It has been a concern that certain types of participants could be more likely to have low compliance, such as those who have severe hearing loss and poor speech recognition performance, are employed, are not familiar with technologies used to implement EMA (e.g., smartphones), and have poorer cognitive abilities. Noncompliance dependent on personal characteristics could negatively impact the generalizability of EMA research. This article aims to determine personal characteristics associated with EMA compliance in a group of adult cochlear implant (CI) candidates and users. An observational study. Fifty-eight adults who were either scheduled to received CIs or were experienced CI users completed the study. Participants conducted smartphone-based EMA designed to assess an individual's daily auditory ecology for 1 week. EMA compliance was quantified using two metrics: the number of completed surveys and the response rate to the notification delivered by the EMA app. Personal characteristics (i.e., predictors) included age, gender, CI status (candidate or user), employment status (employed or not employed), smartphone ownership, speech recognition performance, social network size, level of depressive symptoms, and neurocognitive abilities. A word recognition test, questionnaires, and a test battery of neurocognitive assessments were used to measure the predictors. We used negative binomial regression and logistic mixed models to determine the factors associated with the number of completed surveys and the response rate, respectively. We hypothesized that, for example, employed participants with poorer speech recognition performance would have lower compliance. Contrary to the hypothesis, word recognition score was negatively associated with the number of completed surveys (p = 0.022). Holding all other variables constant, a 10-point (i.e., 10%) word recognition score decrease was associated with an 11% increase in the number of completed surveys. For the response rate, employment status was the only significant predictor (p < 0.0001). Consistent with our hypothesis, the odds of responding to EMA notifications for those who are not employed are 82% higher than the odds for those who are employed. No other studied personal characteristic was associated with compliance. For CI candidates and users, EMA compliance could be affected by personal characteristics such as speech recognition performance and employment status. Because (1) participants with poorer speech recognition performance do not necessarily have lower compliance and (2) most personal characteristics investigated in the present study (e.g., age, gender, smartphone ownership, and neurocognitive abilities) do not predict compliance, a wide range of participants could successfully conduct smartphone-based EMA.

Comparison of the quality-of-life benefit received from cochlear implants and hearing aids among hearing-impaired adults

&lt;p class="abstract"&gt;&lt;strong&gt;Background: &lt;/strong&gt;To compare the quality-of-life (QOL) benefit received from cochlear implants (CIs) and hearing aids (HAs) among hearing-impaired adults. Using Case Control Study design, health-related questionnaire based on indices for audiological data and quality of life (QOL) was prepared. The questionnaire was used to compare the satisfaction level of users of Cochlear Implants with that of Hearing aids.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods: &lt;/strong&gt;Retrospective and prospective data pandemic from December 2019 to May 2021 was collected. Twenty- five cases of adult Cochlear Implant users were compared against equal number of age-matched control cases of users Hearing aids. Questionnaire to assess the influence of either on quality of life was mailed to the receipients.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results: &lt;/strong&gt;Scores for the Hearing aids group matched very well with the scores for the Cochlear Implant group. Overall QoL scores were extensively higher for all 6 subdomains. \Multiple evaluation of variance showed greater QOL benefit in CI than HA users across the physical, psychological, and social subdomains (p&amp;lt;0.001).&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;Cochlear implants provide extensive benefit for those with profound hearing loss as hearing aids bring for those with less severe hearing loss.&lt;/p&gt;&lt;p class="abstract"&gt; &lt;/p&gt;

Long-Term Improvement in Localization for Cochlear Implant Users with Single-Sided Deafness.

To assess whether early, significant improvements in sound source localization observed in cochlear implant (CI) recipients with normal hearing (NH) in the contralateral ear are maintained after 5 years of CI use. Prospective, repeated measures study. Participants were recruited from a sample of CI + NH listeners (n=20) who received their device as part of a prospective clinical trial investigating outcomes of CI use for adult cases of single-sided deafness. Sound source localization was assessed annually after the clinical trial endpoint (1-year post-activation). Listeners were asked to indicate the perceived sound source for a broadband noise burst presented randomly at varied intensity levels from one of 11 speakers along a 180° arc. Performance was quantified as root-mean-squared (RMS) error. Linear mixed models showed superior post-activation performance was maintained with long-term CI use as compared to preoperative abilities (P < .001). Unexpectedly, a significant improvement (P=.009) in sound source localization was observed over the long-term post-activation period (1-5 years). To better understand these long-term findings, the response patterns for the 11 participants who were evaluated at the 1- and 5-year visits were reviewed. This subgroup demonstrated a significant improvement in RMS error (P=.020) and variable error (P=.031), indicating more consistent responses at the 5-year visit. Adult CI + NH listeners experience significant improvements in sound source localization within the initial weeks of listening experience, with additional improvements observed after long-term device use. The present sample demonstrated significant improvements between the 1-year and 5-year visits, with greater accuracy and consistency noted in their response patterns. 3 Laryngoscope, 132:2453-2458, 2022.

Characteristics of the Adaptation Recovery Function of the Auditory Nerve and Its Association With Advanced Age in Postlingually Deafened Adult Cochlear Implant Users.

This study aimed to (1) characterize the amount and the speed of recovery from neural adaptation at the auditory nerve (AN) and (2) assess their associations with advanced age in postlingually deafened adult cochlear implant users. Study participants included 25 postlingually deafened adult, Cochlear Nucleus device users, ranging in age between 24.83 and 83.21 years at the time of testing. The stimulus was a 100-ms pulse train presented at four pulse rates: 500, 900, 1800, and 2400 pulses per second (pps). The pulse trains were presented at the maximum comfortable level measured for the 2400-pps pulse train. The electrically evoked compound action potential (eCAP) evoked by the last pulse of the pulse train (i.e., the probe pulse) was recorded. The remaining pulses of the pulse train served as the pulse-train masker. The time interval between the probe pulse and the last pulse of the pulse-train masker [i.e., masker-probe-interval (MPI)] systematically increased from 0.359 ms up to 256 ms. The adaptation recovery function (ARF) was obtained by plotting normalized eCAP amplitudes (re: the eCAP amplitude measured at the MPI of 256 ms) as a function of MPIs. The adaptation recovery ratio (ARR) was defined as the ratio between the eCAP amplitude measured at the MPI of 256 ms and that measured for the single-pulse stimulus presented at the same stimulation level. The time constants of the ARF were estimated using a mathematical model with an exponential function with up to three components. Generalized Linear Mixed effects Models were used to compare ARRs and time constants measured at different electrode locations and pulse rates, as well as to assess the effect of advanced age on these dependent variables. There were three ARF types observed in this study. The ARF type observed in the same study participant could be different at different electrode locations and/or pulse rates. Substantial variations in both the amount and the speed of neural adaptation recovery among study participants were observed. The ARR was significantly affected by pulse rate but was not affected by electrode location. The effect of electrode location on the time constants of the ARF was not statistically significant. Pulse rate had a statistically significant effect on τ 1, but not on τ 2 or τ 3 . There was no statistically significant effect of age on the ARR or the time constants of the ARF. Neural adaptation recovery processes at the AN demonstrate substantial variations among human cochlear implant users. The recovery pattern can be nonmonotonic with up to three phases. While the amount of neural adaptation recovery decreases as pulse rate increases, only the speed of the first phase of neural adaptation recovery is affected by pulse rate. Electrode location or advanced age has no robust effect on neural adaptation recovery processes at the level of the AN for a 100-ms pulse-train masker with pulse rates of 500 to 2400 pps. The lack of sufficient participants in this study who were 40 years of age or younger at the time of testing might have precluded a thorough assessment of the effect of advanced age.

Experience of adult cochlear implantation at a tertiary hospital.

The prevalence of adult cochlear implant (CI) surgery is increasing. However, the relevant adult CI data in Taiwan are insufficient due to the relatively small number of adult implant patients. The two main factors hindering adult implantation are the high cost of the surgery itself and inadequate knowledge regarding the effectiveness of CI for hearing and suppression of tinnitus. Here, we present data regarding adult CI outcomes from a single tertiary hospital. A total of 116 consecutive adult CI recipients (≥18 years old) who completed at least 12 months of speech perception tests (words and sentences) between January 1999 and December 2020 were enrolled in this retrospective population-based cohort study. Thirty patients completed speech perception (words and sentences) testing as well as three questionnaires relating to quality of life, and 71 completed full tinnitus suppression studies. Subjects' pre- and post-CI questionnaires were evaluated to assess overall CI outcome. For auditory evaluation, the scores of easy sentences (ES), difficult sentences (DS), and phonetically balanced (PB) word recognition tests reached a plateau at 3 months post-CI (p = 0.005, 0.001, and 0.004, respectively) in most subjects. The post-CI scores of bodily pain, mental health, and social role functioning were significantly higher than corresponding pre-CI scores on the SF-36 Health Survey-Taiwan version (p = 0.036, 0.019, and 0.002, respectively). Furthermore, the post-CI scores of basic sound perception, speech production, and advanced sound perception were significantly higher than the corresponding pre-CI scores on the Nijmegen Cochlear Implant Questionnaire (p < 0.001, 0.013, and <0.001, respectively). Self-esteem was significantly correlated with the Categories of Auditory Performance scale and Speech Intelligibility Rating scale at 3, 6, and 9 months post-CI. CI improved tinnitus in approximately 65.1% of 71 adults. Based on the Tinnitus Handicap Inventory, 66.7% of patients were in grade 3-5 before surgery. However, after CI, only 34.4% of patients remained in THI grade 3-5. This study confirmed that CI can improve speech perception (words and sentences), physical health, mental health, social interaction, and self-esteem in adult patients with profound hearing loss. CI also significantly alleviated tinnitus. The outcomes of ES, DS, and PB tests at 3 months post-CI were non-inferior to other longer post-CI periods and could be utilized as references for recovery and evaluation of prognosis.

Benefits of auditory-verbal intervention for adult cochlear implant users: perspectives of users and their coaches

Objective Post-implant rehabilitation is limited for adult cochlear implant (CI) recipients. The objective of this research was to capture the perspectives of CI users and their coaches regarding their experiences with auditory-verbal intervention as an example of post-implant rehabilitation and their views on perceived benefits and challenges related to the intervention. Design This qualitative study involved semi-structured focus group interviews with adult CI users and their coaches who accompanied them in a 24-week auditory-verbal intervention program. Study sample A total of 17 participants (eight CI users and nine coaches) contributed to the interviews. Results Three key topic areas emerged from the interviews capturing CI users’ and coaches’ experiences related to the intervention program: (1) benefits of the intervention, (2) factors affecting experiences, and (3) challenges and barriers. Benefits included increased confidence in hearing, communication, social participation, and new knowledge about technology and hearing. Factors affecting the experience were participants’ motivation and the therapist’s skills. The primary challenge was the time commitment for weekly therapy. Conclusions Both CI users and coaches perceived a focussed auditory-verbal intervention to be beneficial in improving speech understanding, confidence in using hearing, social interaction, and knowledge about technology. Participants recommended reducing the intensity of intervention to facilitate participation.

Neural Adaptation of the Electrically Stimulated Auditory Nerve Is Not Affected by Advanced Age in Postlingually Deafened, Middle-aged, and Elderly Adult Cochlear Implant Users.

This study aimed to investigate the associations between advanced age and the amount and the speed of neural adaptation of the electrically stimulated auditory nerve (AN) in postlingually deafened adult cochlear implant (CI) users. Study participants included 26 postlingually deafened adult CI users, ranging in age between 28.7 and 84.0 years (mean: 63.8 years, SD: 14.4 years) at the time of testing. All study participants used a Cochlear Nucleus device with a full electrode array insertion in the test ear. The stimulus was a 100-ms pulse train with a pulse rate of 500, 900, 1800, or 2400 pulses per second (pps) per channel. The stimulus was presented at the maximum comfortable level measured at 2400 pps with a presentation rate of 2 Hz. Neural adaptation of the AN was evaluated using electrophysiological measures of the electrically evoked compound action potential (eCAP). The amount of neural adaptation was quantified by the adaptation index (AI) within three time windows: around 0 to 8 ms (window 1), 44 to 50 ms (window 2), and 94 to 100 ms (window 3). The speed of neural adaptation was quantified using a two-parameter power law estimation. In 23 participants, four electrodes across the electrode array were tested. In three participants, three electrodes were tested. Results measured at different electrode locations were averaged for each participant at each pulse rate to get an overall representation of neural adaptation properties of the AN across the cochlea. Linear-mixed models (LMMs) were used (1) to evaluate the effects of age at testing and pulse rate on the speed of neural adaptation and (2) to assess the effects of age at testing, pulse rate, and duration of stimulation (i.e., time window) on the amount of neural adaptation in these participants. There was substantial variability in both the amount and the speed of neural adaptation of the AN among study participants. The amount and the speed of neural adaptation increased at higher pulse rates. In addition, larger amounts of adaptation were observed for longer durations of stimulation. There was no significant effect of age on the speed or the amount of neural adaptation. The amount and the speed of neural adaptation of the AN are affected by both the pulse rate and the duration of stimulation, with higher pulse rates and longer durations of stimulation leading to faster and greater neural adaptation. Advanced age does not affect neural adaptation of the AN in postlingually deafened, middle-aged and elderly adult CI users.

Single-Channel Focused Thresholds Relate to Vowel Identification in Pediatric and Adult Cochlear Implant Listeners.

Speech recognition outcomes are highly variable among pediatric and adult cochlear implant (CI) listeners. Although there is some evidence that the quality of the electrode-neuron interface (ENI) contributes to this large variability in auditory perception, its relationship with speech outcomes is not well understood. Single-channel auditory detection thresholds measured in response to focused electrical fields (i.e., focused thresholds) are sensitive to properties of ENI quality, including electrode-neuron distance, intracochlear resistance, and neural health. In the present study, focused thresholds and speech perception abilities were assessed in 15 children and 21 adult CI listeners. Focused thresholds were measured for all active electrodes using a fast sweep procedure. Speech perception performance was evaluated by assessing listeners’ ability to identify vowels presented in /h-vowel-d/ context. Consistent with prior literature, focused thresholds were lower for children than for adults, but vowel identification did not differ significantly across age groups. Higher across-array average focused thresholds, which may indicate a relatively poor ENI quality, were associated with poorer vowel identification scores in both children and adults. Adult CI listeners with longer durations of deafness had higher focused thresholds. Findings from this study demonstrate that poor-quality ENIs may contribute to reduced speech outcomes for pediatric and adult CI listeners. Estimates of ENI quality (e.g., focused thresholds) may assist in developing customized programming interventions that serve to improve the transmission of spectral cues that are important in vowel identification.