Computer-based Auditory Training by New Adult Cochlear Implant Recipients Is Associated With Durable Improvements in Cochlear Implant Quality of Life.

OBJECTIVE: The process of adapting to communicate with a cochlear implant (CI) is complex. The use of auditory training after cochlear implantation may help to facilitate improvements in postoperative speech recognition and quality-of-life outcomes in new adult CI recipients. However, the effectiveness of auditory training remains uncertain and long-term effects have not been examined in a large sample of new adult CI users. As such, the objective of this study was to examine the influence of common forms of auditory training on speech recognition and CI-related quality-of-life (CI-related QOL) outcomes at 1 year after cochlear implantation. We hypothesized that patients who reported use of computer-based auditory training (CBAT) would show improved speech and CIQOL-35 Profile scores at 1 year after activation of their implant, compared with their peers. DESIGN: This study was designed as a prospective study and was undertaken at a tertiary academic CI center. Participants included 114 adults undergoing cochlear implantation for bilateral hearing loss. Patients serially self-reported use of the following types of post-CI auditory training over their first-year postactivation: (1) face-to-face training (e.g., speech-language pathologist), (2) passive home-based training (e.g., listening to audiobooks), and (3) CBAT (e.g., self-directed software). Outcomes measures for this study included change in Consonant-Nucleus-Consonant phoneme (CNCp), CNC word (CNCw), AzBio sentences in quiet, and CIQOL-35 Profile global and domain scores from pre-CI to 12-mo post-CI. RESULTS: Of 114 patients, 94 (82.5%) used one or more auditory training resources. Of these, 19.3% used face-to-face training, 67.5% passive home-based training, and 46.5% CBAT. Of 114 patients, 73 had complete CIQOL data. At 12 mo, only CBAT use was associated with significantly greater improvements in global and all domain-specific CIQOL scores (d-range = 0.72-0.87), compared with those not using CBAT. Controlling for demographics and use of multiple training resources, CBAT remained the strongest positive predictor of CIQOL improvement, with significant associations with global score (ß = 12.019[4.127,19.9]) and all domain scores at 12-mo post-CI: communication (ß = 11.937[2.456,21.318), emotional (ß = 12.293[1.827,22.759), entertainment (ß = 17.014[5.434,28.774), environment (ß = 13.771[1.814,25.727]), listening effort (ß = 12.523[2.798,22.248]), and social (ß = 18.114[7.403,28.826]). No significant benefits were noted with use of CBAT or any other form of auditory training and speech recognition scores at 12-mo post-CI (d-range = -0.12-0.22). CONCLUSIONS: Auditory training with CBAT was associated with improved CI-related QOL outcomes at 12-mo post-CI. Given its availability and low cost, this study provides evidence to support using CBAT to improve real-world functional abilities in new adult CI recipients.

Patient and device factors contributing to electrically-evoked stapedial reflex thresholds in cochlear implanted adults.

INTRODUCTION: Optimal cochlear implant (CI) outcomes are due to, at least in part, appropriate device programming. Objective measures, such as electrically-evoked stapedial reflex thresholds (ESRTs), can be used to more accurately set programming levels. However, underlying factors that contribute to ESRT levels are not well understood. The objective of the current study is to analyze how demographic variables of patient sex and age, along with cochlear implant electrode location, influence electrically-evoked stapedial reflex thresholds (ESRTs) in adult cochlear implant users. METHODS: A single institution retrospective review was performed. Electronic medical records, cochlear implant programming records, and clinic database of post-operative computerized tomography were reviewed to gather information regarding patient demographics, ESRTs, and electrode array metrics including medial-lateral distance and scalar location. Linear mixed models were constructed to determine how demographic variables and electrode position influence ESRTs recorded in 138 adult CI recipients. RESULTS: ESRTs were significantly affected by recipient age, with older listeners demonstrating higher ESRT levels. On average, males had higher ESRT levels when compared to females. In a subset of the study sample, ESRT levels increased with increasing medial-lateral distance, however, there was not a statistically significant effect of electrode type (lateral/straight arrays compared to perimodiolar arrays). ESRTs were not affected by scalar location. DISCUSSION/CONCLUSIONS: The results suggest that key demographic and electrode position characteristics influence the level of ESRTs in adult CI recipients. While ESRTs are widely used to assist with CI programming, underlying factors are not well understood. The significant factors of aging and sex could be due to middle ear mechanics or neural health differences, however further data are needed to better understand these associations.

Frequency-to-Place Mismatch Impacts Cochlear Implant Quality of Life, But Not Speech Recognition.

OBJECTIVE: To retrospectively compare frequency-place mismatch among adult cochlear implant (CI) recipients with lateral wall (LW) and perimodiolar/Mid Scala (PM/MS) arrays, and to quantify the impact of these factors on early post-activation (3 months) speech recognition abilities and CI-specific quality of life. METHODS: One hundred and twenty-six adult participants were separated into two groups: (1) 83 participants who underwent CI with a PM/MS array and 43 patients who underwent CI with a LW array. All participants completed the Cochlear Implant Quality of Life Profile (CIQOL-35 Profile) instrument. Angular insertion depth and semitone mismatch, which contribute to frequency-place mismatch, were assessed using post-operative CT scans. Word and speech recognition in quiet were determined using the Consonant-Nucleus-Consonant (CNC) and the AzBio tests, respectively (n = 82 patients). RESULTS: LW arrays were more deeply inserted and exhibited less semitone mismatch compared to PM/MS arrays. No significant relationship was found between semitone mismatch and early post-operative speech perception scores for either PM/MS or LW arrays. However, greater degrees of semitone mismatch were associated with lower CIQOL-35 profile scores for PM/MS arrays. CONCLUSIONS AND RELEVANCE: The results of this study indicate that both the degree of frequency-place mismatch, and its impact on CI-specific quality of life, vary by CI array design. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:2898-2905, 2024.

Systematic Review of Auditory Training Outcomes in Adult Cochlear Implant Recipients and Meta-Analysis of Outcomes.

Objective: to review evidence on the efficacy of auditory training in adult cochlear implant recipients. Data Sources: PRISMA guidelines for a systematic review of the literature were followed. PubMed, Scopus, and CINAHL databases were queried on 29 June 2023 for terms involving cochlear implantation and auditory training. Studies were limited to the English language and adult patient populations. Study Selection: Three authors independently reviewed publications for inclusion in the review based on a priori inclusion and exclusion criteria. Inclusion criteria encompassed adult cochlear implant populations, an analysis of clinician- or patient-directed auditory training, and an analysis of one or more measures of speech recognition and/or patient-reported outcome. Exclusion criteria included studies with only pediatric implant populations, music or localization training in isolation, and single-sample case studies. Data Extraction: The data were collected regarding study design, patient population, auditory training modality, auditory training timing, speech outcomes, and data on the durability of outcomes. A quality assessment of the literature was performed using a quality metric adapted from the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group guidelines. Data Synthesis and Meta-Analysis: Data were qualitatively summarized for 23 studies. All but four studies demonstrated significant improvement in at least one measured or patient-reported outcome measure with training. For 11 studies with sufficient data reporting, pre-intervention and post-intervention pooled means of different outcome measures were compared for 132 patients using meta-analysis. Patient-direct training was associated with significant improvement in vowel-phoneme recognition and speech recognition in noise (p < 0.05 and p < 0.001, respectively), and clinician-directed training showed significant improvement in sentence recognition in noise (p < 0.001). Conclusions: The literature on auditory training for adult cochlear implant recipients is limited and heterogeneous, including a small number of studies with limited levels of evidence and external validity. However, the current evidence suggests that auditory training can improve speech recognition in adult cochlear implant recipients.

Determinants of Cochlear Implant Satisfaction and Decisional Regret in Adult Cochlear Implant Users.

OBJECTIVE: Determine associations expected and actual cochlear implant (CI) outcomes, decisional regret, and satisfaction in experienced adult CI users. STUDY DESIGN: Cross-sectional cohort study. SETTING: Tertiary medical center. PATIENTS: Thirty-nine adult CI users meeting traditional bilateral hearing loss indications with ≥12 months CI experience. INTERVENTIONS/MAIN OUTCOME MEASURES: Patients completed the validated Satisfaction with Amplification in Daily Living and Decisional Regret instruments. Pre- and post-CI outcomes (CI Quality of Life [CIQOL]-Expectations; CIQOL-35 Profile; CNC words, AzBio Sentences) were obtained from a prospectively maintained clinical database. RESULTS: Using established cutoff scores, 29% of patients reported a substantial degree of post-CI decisional regret. For each CIQOL domain, patients without decisional regret obtained post-CI outcome scores closer to pre-CI expectations compared with patients with decisional regret ( d = 0.34 to 0.91); similar results were observed with higher CI user satisfaction ( d = 0.17-0.83). Notably, the degree of pre- to post-CI improvement in CNC or AzBio scores did not differ between patients with and without decisional regret or with lower and higher satisfaction. Finally, greater pre-/postimprovement in CIQOL-35 Profile domain scores demonstrated far stronger associations with lower decisional regret and higher satisfaction than changes in speech recognition scores. CONCLUSIONS: Patients with better alignment of their pre-CI expectations and post-CI outcomes and greater pre-/post-CIQOL improvement had lower decisional regret and higher satisfaction. This emphasizes the importance of evidence-based pre-CI counseling regarding real-world CI benefits and caution against assuming that improvements in speech recognition are related to patient satisfaction.

Impact of auditory environments on language outcomes in children with a cochlear implant.

OBJECTIVES: To analyse the effects of auditory environments on receptive and expressive language outcomes in children with a CI. DESIGN: A single-institution retrospective review was performed. The auditory environments included Speech-Noise, Speech-Quiet, Quiet, Music, and Noise. Hearing Hour Percentage (HHP) and percent total hours were calculated for each environment. Generalised Linear Mixed Models (GLMM) analyses were used to study the effects of auditory environments on PLS Receptive and Expressive scores. STUDY SAMPLE: Thirty-nine children with CI. RESULTS: On GLMM, an increase in Quiet HHP and Quiet percent total hours were positively associated with PLS Receptive scores. Speech-Quiet, Quiet, and Music HHP were positively associated with PLS Expressive scores, with only Quiet being significant for percent total hours. In contrast, percent total hours of Speech-Noise and Noise had a significant negative association with PLS Expressive scores. CONCLUSIONS: This study suggests that more time spent in a quiet auditory environment positively influences PLS Receptive and Expressive scores and that more time listening to speech in quiet and music positively influences PLS Expressive scores. Time spent in environments recognised as Speech-Noise and Noise might negatively impact a child's expressive language outcomes with a CI. Future research is needed to better understand this association.

Reversing Synchronized Brain Circuits Using Targeted Auditory-Somatosensory Stimulation to Treat Phantom Percepts: A Randomized Clinical Trial.

Importance: Animal models have shown altered dorsal cochlear nucleus circuitry in animals that develop tinnitus; however, precise treatment using bisensory (auditory and somatosensory) stimuli can reverse altered neural patterns and lessen tinnitus. Objective: To confirm and extend the findings of a pilot study, which suggested an increased efficacy of bisensory stimulation, to a clinical trial with a greater duration and greater number of participants. Design, Setting, and Participants: This double-blind, crossover, single-center randomized clinical trial was conducted from March 2019, with a 3-month follow-up per participant ending in July 2022. Eligible adults were recruited from the University of Michigan Health System in Ann Arbor, Michigan. Eligibility criteria included bothersome tinnitus (Tinnitus Functional Index [TFI] score, ≥17 points), somatic tinnitus, normal to moderate hearing loss, and no other tinnitus treatments in the 6 months prior to the trial. Included participants were randomized to either treatment group 1, which received active (bisensory) treatment, or group 2, which received the control (auditory-only) treatment. Results were analyzed using intent-to-treat (ITT) and per protocol (PP) populations. Intervention: Precisely timed bisensory (combined auditory and somatosensory) treatment was delivered through a portable, custom, take-home device that was provided to each participant for daily, at-home treatments. Group 1 participants received 30 minutes per day of the bisensory treatment for 6 weeks, followed by a 6-week washout phase, and then 30 minutes per day of the auditory-only treatment followed by a second 6-week washout phase. Group 2 participants received the auditory-only treatment first, followed by a washout phase, and then the bisensory treatment followed by a second washout phase. Main Outcomes and Measures: Primary end points were changes in TFI score and tinnitus loudness level from baseline through week 6 and week 12. Results: Of 337 screened individuals, 99 (mean [SD] age, 47 [12.7] years; 59 males [60%]; 85 with non-Hispanic White [86%] race and ethnicity) were enrolled into the study and randomized to treatment group 1 (n = 49) or group 2 (n = 50). The active but not the control treatment resulted in clinically significant decreases in TFI scores at week 6 of phase 1 (ITT population: -12.0 [95% CI, -16.9 to -7.9] points; P < .001; PP population: -13.2 [95% CI, -16.0 to -10.5] points; P < .001). Decreases in tinnitus loudness level were greater than 6 dB sensation level (SL; >half as loud) at week 6 for the bisensory treatment group, with little effect for the auditory-only treatment control group at week 6 of phase 1 (ITT population: -5.8 [95% CI, -9.5 to -2.2] dB; P = .08; PP population: -7.2 [95% CI, -11.4 to -3.1] dB; P = .03), and up to 11 dB SL at week 12 of phase 2 (ITT population: -10.9 [95% CI, -15.2 to -6.5] dB; P = .001; PP population: -14.1 [95% CI, -18.4 to -9.8] dB; P < .001). Decreased tinnitus loudness level and TFI scores extended into the washout phase, indicating a prolonged treatment effect. Conclusions and Relevance: This trial found that precisely timed bisensory treatment using stimuli and timing developed in a validated animal model was effective for adults with somatic tinnitus. Prolonged reduction in tinnitus symptoms can result from using an extended treatment duration. Trial Registration: ClinicalTrials.gov Identifier: NCT03621735.

Reexamining the effects of electrode location on measures of neural health in cochlear implant users.

The electrically evoked compound action potentials (ECAPs) amplitude-growth function (AGF) slope correlates with spiral ganglion neuron (SGN) density in the cochlear implanted cochlea. Electrode insertion angle and medial-lateral distance covary from base to apex; in some human ears, SGN survival varies from base to apex, making it difficult to parse out contributing factors to the ECAP AGF slope. Evoked compound action potentials were analyzed on each electrode and compared to post-operative computerized tomography scans. When controlling for medial-lateral distance, insertion angle does not influence ECAP AGF slope.

Why Do Candidates Forgo Cochlear Implantation?

OBJECTIVE: Identify barriers and facilitating factors in cochlear implant (CI) utilization by comparing functional measures between CI candidates who undergo or forgo implantation. METHODS: Forty-three participants were separated into two groups: (1) 28 participants who underwent CI and (2) 15 participants who elected not to proceed with CI despite meeting eligibility criteria (no-CI). Prior to implantation, all participants completed the CI Quality of Life (CIQOL)-35 Profile and CIQOL-Expectations instrument. They were also surveyed on factors contributing to their decision to either undergo or forgo CI. Word and speech recognition were determined using the Consonant-Nucleus-Consonant (CNC) and the AzBio tests, respectively. RESULTS: CIQOL-Expectations scores were indistinguishable between groups, but there were substantial differences in baseline CIQOL-35 Profile scores. Compared to the CI group, the no-CI group exhibited higher pre-CI scores in the Emotional (Cohen's d [95% CI] = 0.8 [0.1, 1.5]) and Entertainment (Cohen's d [95% CI] = 0.8 [0.1, 1.5]) domains. Survey data revealed that the most commonly reported barriers to pursuing CI in the no-CI cohort were fear of surgical complications (85%), cost associated with implantation (85%), and perception that hearing was not poor enough for CI surgery (85%). CONCLUSIONS AND RELEVANCE: The results of this study indicate that functional outcome expectations are similar between candidates who elect to receive or forgo CI, yet those who forgo CI have higher baseline CI-specific QOL abilities. LEVEL OF EVIDENCE: 4 Laryngoscope, 133:3548-3553, 2023.

Association of Cognitive Impairment Screening Scores With Improvements in Speech Recognition and Quality of Life After Cochlear Implantation.

Importance: Many cochlear implant centers screen patients for cognitive impairment as part of the evaluation process, but the utility of these scores in predicting cochlear implant outcomes is unknown. Objective: To determine whether there is an association between cognitive impairment screening scores and cochlear implant outcomes. Design, Setting, and Participants: Retrospective case series of adult cochlear implant recipients who underwent preoperative cognitive impairment screening with the Montreal Cognitive Assessment (MoCA) from 2018 to 2020 with 1-year follow-up at a single tertiary cochlear implant center. Data analysis was performed on data from January 2018 through December 2021. Exposures: Cochlear implantation. Main Outcomes and Measures: Preoperative MoCA scores and mean (SD) improvement (aided preoperative to 12-month postoperative) in Consonant-Nucleus-Consonant phonemes (CNCp) and words (CNCw), AzBio sentences in quiet (AzBio Quiet), and Cochlear Implant Quality of Life-35 (CIQOL-35) Profile domain and global scores. Results: A total of 52 patients were included, 27 (52%) of whom were male and 46 (88%) were White; mean (SD) age at implantation was 68.2 (13.3) years. Twenty-three (44%) had MoCA scores suggesting mild and 1 (2%) had scores suggesting moderate cognitive impairment. None had been previously diagnosed with cognitive impairment. There were small to medium effects of the association between 12-month postoperative improvement in speech recognition measures and screening positive or not for cognitive impairment (CNCw mean [SD]: 48.4 [21.9] vs 38.5 [26.6] [d = -0.43 (95% CI, -1.02 to 0.16)]; AzBio Quiet mean [SD]: 47.5 [34.3] vs 44.7 [33.1] [d = -0.08 (95% CI, -0.64 to 0.47)]). Similarly, small to large effects of the associations between 12-month postoperative change in CIQOL-35 scores and screening positive or not for cognitive impairment were found (global: d = 0.32 [95% CI, -0.59 to 1.23]; communication: d = 0.62 [95% CI, -0.31 to 1.54]; emotional: d = 0.26 [95% CI, -0.66 to 1.16]; entertainment: d = -0.005 [95% CI, -0.91 to 0.9]; environmental: d = -0.92 [95% CI, -1.86 to 0.46]; listening effort: d = -0.79 [95% CI, -1.65 to 0.22]; social: d = -0.51 [95% CI, -1.43 to 0.42]). Conclusions and Relevance: In this case series, screening scores were not associated with the degree of improvement of speech recognition or patient-reported outcome measures after cochlear implantation. Given the prevalence of screening positive for cognitive impairment before cochlear implantation, preoperative screening can be useful for early identification of potential cognitive decline. These findings support that screening scores may have a limited role in preoperative counseling of outcomes and should not be used to limit candidacy.

Cochlear Health and Cochlear-implant Function.

The cochlear implant (CI) is widely considered to be one of the most innovative and successful neuroprosthetic treatments developed to date. Although outcomes vary, CIs are able to effectively improve hearing in nearly all recipients and can substantially improve speech understanding and quality of life for patients with significant hearing loss. A wealth of research has focused on underlying factors that contribute to success with a CI, and recent evidence suggests that the overall health of the cochlea could potentially play a larger role than previously recognized. This article defines and reviews attributes of cochlear health and describes procedures to evaluate cochlear health in humans and animal models in order to examine the effects of cochlear health on performance with a CI. Lastly, we describe how future biologic approaches can be used to preserve and/or enhance cochlear health in order to maximize performance for individual CI recipients.

Patient-Related Factors Do Not Predict Use of Computer-Based Auditory Training by New Adult Cochlear Implant Recipients.

OBJECTIVE: The use of computer-based auditory training (CBAT) after cochlear implantation is associated with improved speech recognition and real-world functional abilities. However, patient-related factors associated with CBAT use remain unknown. This study seeks to identify such factors and recognize those at risk for not implementing CBAT. STUDY DESIGN: Prospective natural experiment. SETTING: Tertiary academic center. PATIENTS: A total of 117 new adult cochlear implant (CI) recipients with bilateral moderate-to-profound hearing loss. INTERVENTIONS/MAIN OUTCOME MEASURES: Patient demographic and lifestyle information, preimplantation aided speech recognition scores, Cochlear Implant Quality of Life (CIQOL) domain and global scores, CIQOL-Expectations scores, and CBAT use in the first 3 months after activation. Patient-related variables included age, sex, race, duration of hearing loss before implantation, hours of CI use per day, hearing-aid use before implantation, living arrangements/marital status, annual household income, employment, technology use, and education. RESULTS: Overall, 33 new CI users (28.2%) used CBAT in the first 3 months after activation. On bivariate analysis of the pre-CI CIQOL scores, CIQOL-Expectations score, aided speech recognition scores, and demographic/lifestyle factors examined, regular use of smartphone, tablet, or computer technology was significantly associated with an increased likelihood of CBAT use (odds ratio, 9.354 [1.198-73.020]), whereas higher CIQOL-Expectations emotional domain scores were associated with a lower likelihood of CBAT use (d = -0.69 [-1.34 to -0.05]). However, using multivariable analysis to control for potential confounding factors revealed no significant associations between CBAT use in the first 3 months after cochlear implantation and any examined factor. CONCLUSIONS: No associations between patient demographic, lifestyle, or pre-CI speech recognition and patient-reported outcome measures and CBAT use were identified. Therefore, discussions with all patients after implantation on the availability of CBAT and its potential benefits are warranted. In addition, given the limited overall use of CBAT and its association with improved CI outcomes, future studies are needed to investigate facilitators and barriers to CBAT use.

Association of Aging and Cognition With Complex Speech Understanding in Cochlear-Implanted Adults: Use of a Modified National Institutes of Health (NIH) Toolbox Cognitive Assessment.

Importance: The association between cognitive function and outcomes in cochlear implant (CI) users is not completely understood, partly because some cognitive tests are confounded by auditory status. It is important to determine appropriate cognitive tests to use in a cohort of CI recipients. Objective: To provide proof-of-concept for using an adapted version of the National Institutes of Health (NIH) Toolbox Cognition Battery in a cohort of patients with CIs and to explore how hearing in noise with a CI is affected by cognitive status using the adapted test. Design, Setting, and Participants: In this prognostic study, participants listened to sentences presented in a speech-shaped background noise. Cognitive tests consisted of 7 subtests of the NIH Toolbox Cognition Battery that were adapted for hearing impaired individuals by including written instructions and visual stimuli. Participants were prospectively recruited from and evaluated at a tertiary medical center. All participants had at least 6 months' experience with their CI. Main Outcomes and Measures: The main outcomes were performance on the adapted cognitive test and a speech recognition in noise task. Results: Participants were 20 adult perilingually or postlingually deafened CI users (50% male participants; median [range] age, 66 [26-80] years old). Performance on a sentence recognition in noise task was negatively associated with the chronological age of the listener (R2 = 0.29; ß = 0.16; standard error, SE = 0.06; t = 2.63; 95% confidence interval, 0.03-0.27). Testing using the adapted version of the NIH Toolbox Cognition Battery revealed that a test of processing speed was also associated with performance, using a standardized score that accounted for contributions of other demographic factors (R2 = 0.28; 95% confidence interval, -0.42 to -0.05). Conclusions and Relevance: In this prognostic study, older CI users showed poorer performance on a sentence-in-noise test compared with younger users. This poorer performance was correlated with a cognitive deficit in processing speed when cognitive function was assessed using a test battery adapted for participants with hearing loss. These results provide initial proof-of-concept results for using a standardized and adapted cognitive test battery in CI recipients.

Longitudinal Speech Recognition Changes After Cochlear Implant: Systematic Review and Meta-analysis.

OBJECTIVES: To examine patterns of change and plateau in speech recognition scores in postlingually hearing impaired adult cochlear implant recipients. The study also examines variations in change patterns for different speech materials and testing conditions. STUDY DESIGN: Used systematic review with meta-analysis. METHODS: Articles in English reporting speech recognition scores of adults with postlingual hearing loss at pre-implantation and at least two post-implantation time points were included. Statistically significant changes were determined by meta-analysis and the 95% confidence interval. RESULTS: A total of 22 articles representing 1954 patients were included. Meta-analysis of mean difference demonstrated significant improvements in speech recognition score for words in quiet (37.4%; 95% confidence interval [34.7%, 40.7%]), sentences in quiet (49.4%; 95% confidence interval [44.9%, 53.9%]), and sentences in noise (30.8%; 95% confidence interval [25.2%, 36.4%]) from pre-op to 3 months. Scores continued to increase from 3 to 12 months but did not reach significance. Similarly, significant improvements from pre-op to 3 months were observed for consonant nucleus consonant (CNC) words in quiet (37.1%; 95% confidence interval [33.8%, 40.4%]), hearing in noise test (HINT) sentences in quiet (46.5%; 95% confidence interval [37.0%, 56.0%]), AzBio sentences in quiet (45.9%; 95% confidence interval [44.2%, 47.5%]), and AzBio sentences in noise (26.4%; 95% confidence interval [18.6%, 34.2%]). HINT sentences in noise demonstrated improvement from pre-op to 3 months (35.1%; 95% confidence interval [30.0%, 40.3%]) and from 3 to 12 months (15.5%; 95% confidence interval [7.2%, 23.8%]). CONCLUSIONS: Mean speech recognition scores demonstrate significant improvement within the first 3 months, with no further statistically significant improvement after 3 months. However, large individual variation should be expected and future research is needed to explain the sources of these individual differences. Laryngoscope, 133:1014-1024, 2023.

Use of Auditory Training and Its Influence on Early Cochlear Implant Outcomes in Adults.

OBJECTIVE: Assess associations between postcochlear implant (CI) auditory training and early outcomes related to speech recognition and CI quality of life (CIQOL). STUDY DESIGN: Longitudinal, prospective cohort. SETTING: Tertiary academic center. PATIENTS: Seventy-two adults undergoing cochlear implantation for bilateral severe-to-profound hearing loss. INTERVENTIONS: Self-reported use of three categories of auditory training post-CI activation: (1) face-to-face training (e.g., speech pathologist), (2) passive home-based training (e.g., listening to audiobooks), and (3) computer-based training (e.g., interactive software). MAIN OUTCOME MEASURES: Change in Consonant-Nucleus-Consonant phoneme (CNCp), CNC word (CNCw), AzBio sentences in quiet, and CIQOL-35 Profile global and domain scores from pre-CI to 3-month post-CI. RESULTS: Of 72 patients, 52 (72.2%) used an auditory training resource. Of all patients, 18.4% used face-to-face training, 58.3% passive home-based training, and 33.3% computer-based training. At 3 months post-CI, use of any training was associated with greater improvement in speech recognition (d-range = 0.57-0.85) and global and domain-specific CIQOL scores, except entertainment (d-range = -0.33 to 0.77). Use of computer-based training demonstrated the greatest effect, with larger improvements in speech recognition (CNCp: d = 0.69[0.03,1.35]; CNCw: d = 0.80[0.14,1.46]; AzBio: d = 1.11[0.44,1.77]) and global and all domain-specific CIQOL scores (d-range = 0.05-1.35). Controlling for age, sex, household income, and use of multiple training resources, computer-based training remained the strongest positive predictor of speech recognition and CIQOL improvement, with significant associations with CNCp (ß = 33.07[1,43,64.719]), AzBio (ß = 33.03[5.71,60.35]), and CIQOL-global (ß = 10.92[1.15,20.70]) score improvement. CONCLUSIONS: Our findings provide preliminary evidence-based recommendations for use of specific auditory training resources for new adult CI recipients. Auditory training, especially self-directed computer software, resulted in improved speech recognition and CIQOL outcomes after 3 months and are widely available for CI users.

A Broadly Applicable Method for Characterizing the Slope of the Electrically Evoked Compound Action Potential Amplitude Growth Function.

OBJECTIVES: Amplitudes of electrically evoked compound action potentials (eCAPs) as a function of the stimulation level constitute the eCAP amplitude growth function (AGF). The slope of the eCAP AGF (i.e., rate of growth of eCAP amplitude as a function of stimulation level), recorded from subjects with cochlear implants (CIs), has been widely used as an indicator of survival of cochlear nerve fibers. However, substantial variation in the approach used to calculate the slope of the eCAP AGF makes it difficult to compare results across studies. In this study, we developed an improved slope-fitting method by addressing the limitations of previously used approaches and ensuring its application for the estimation of the maximum slopes of the eCAP AGFs recorded in both animal models and human listeners with various etiologies. DESIGN: The new eCAP AGF fitting method was designed based on sliding window linear regression. Slopes of the eCAP AGF estimated using this new fitting method were calculated and compared with those estimated using four other fitting methods reported in the literature. These four methods were nonlinear regression with a sigmoid function, linear regression, gradient calculation, and boxcar smoothing. The comparison was based on the fitting results of 72 eCAP AGFs recorded from 18 acutely implanted guinea pigs, 46 eCAP AGFs recorded from 23 chronically implanted guinea pigs, and 2094 eCAP AGFs recorded from 200 human CI users from 4 patient populations. The effect of the choice of input units of the eCAP AGF (linear versus logarithmic) on fitting results was also evaluated. RESULTS: The slope of the eCAP AGF was significantly influenced by the slope-fitting method and by the choice of input units. Overall, slopes estimated using all five fitting methods reflected known patterns of neural survival in human patient populations and were significantly correlated with speech perception scores. However, slopes estimated using the newly developed method showed the highest correlation with spiral ganglion neuron density among all five fitting methods for animal models. In addition, this new method could reliably and accurately estimate the slope for 4 human patient populations, while the performance of the other methods was highly influenced by the morphology of the eCAP AGF. CONCLUSIONS: The novel slope-fitting method presented in this study addressed the limitations of the other methods reported in the literature and successfully characterized the slope of the eCAP AGF for various animal models and CI patient populations. This method may be useful for researchers in conducting scientific studies and for clinicians in providing clinical care for CI users.

Using the electrically-evoked compound action potential (ECAP) interphase gap effect to select electrode stimulation sites in cochlear implant users.

Studies in cochlear implanted animals show that the IPG Effect for ECAP growth functions (i.e., the magnitude of the change in ECAP amplitude growth function (AGF) slope or peak amplitude when the interphase gap (IPG) is increased) can be used to estimate the densities of spiral ganglion neurons (SGNs) near the electrode stimulation and recording sites. In humans, the same ECAP IPG Effect measures correlate with speech recognition performance. The present study examined the efficacy of selecting electrode sites for stimulation based on the IPG Effect, in order to improve performance of CI users on speech recognition tasks. We measured the ECAP IPG Effect for peak amplitude in adult (>18 years old) CI users (N= 18 ears), and created experimental programs to stimulate electrodes with either the highest or lowest ECAP IPG Effect for peak amplitude. Subjects also listened to a program without any electrodes deactivated. In a subset of subject ears (11/18), we compared performance differences between the experimental programs to post-operative computerized tomography (CT) scans to examine underlying factors that might contribute to the efficacy of an electrode site-selection approach. For sentences-in-noise, average performance was better when subjects listened to the experimental program that stimulated electrodes with the highest rather than the lowest IPG Effect for ECAP peak amplitude. A similar pattern was noted for transmission and perception of consonant place cues in a consonant recognition task. However, on average, performance when listening to a program with higher IPG Effect values was equal to that when listening with all electrodes activated. Results also suggest that scalar location (scala tympani or vestibuli) should be considered when using an ECAP-based electrode site-selection procedure to optimize CI performance.

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.

How electrically evoked compound action potentials in chronically implanted guinea pigs relate to auditory nerve health and electrode impedance.

This study examined how multiple measures based on the electrically evoked compound action potential (ECAP) amplitude-growth functions (AGFs) were related to estimates of neural [spiral ganglion neuron (SGN) density and cell size] and electrode impedance measures in 34 specific pathogen free pigmented guinea pigs that were chronically implanted (4.9-15.4 months) with a cochlear implant electrode array. Two interphase gaps (IPGs) were used for the biphasic pulses and the effect of the IPG on each ECAP measure was measured ("IPG effect"). When using a stimulus with a constant IPG, SGN density was related to the across-subject variance in ECAP AGF linear slope, peak amplitude, and N1 latency. The SGN density values also help to explain a significant proportion of variance in the IPG effect for AGF linear slope and peak amplitude measures. Regression modeling revealed that SGN density was the primary dependent variable contributing to across-subject variance for ECAP measures; SGN cell size did not significantly improve the fitting of the model. Results showed that simple impedance measures were weakly related to most ECAP measures but did not typically improve the fit of the regression model.

Development of a 60/60 Guideline for Referring Adults for a Traditional Cochlear Implant Candidacy Evaluation.

OBJECTIVE: To evaluate the effectiveness of a 60/60 referral guideline for identifying patients who should be referred for a cochlear implant candidacy evaluation (CICE), which states patients should be referred if they demonstrate a best ear unaided monosyllabic word score less than or equal to 60% correct and if they demonstrate an unaided pure-tone average in their better ear that is greater than or equal to 60 dB HL. STUDY DESIGN: Retrospective review of data from adults who participated in a CICE. SETTING: A single tertiary medical facility. PATIENTS: Five hundred twenty-nine patients who participated in a CICE. INTERVENTION: CICEs included unaided threshold assessment, unaided speech recognition, and aided word and sentence testing. MAIN OUTCOME MEASURE: Ninety-five percent of patients who met traditional indications for a cochlear implant (n = 250) had a pure-tone average that was greater than or equal to 60 dB, while 92% had a better ear unaided monosyllabic word score that was less than or equal to 60%. RESULTS: If used as a screening measure, the 60/60 measure resulted in a 96% detection rate and a 34% false-positive rate for identifying adults who would meet traditional indications for a cochlear implant. CONCLUSIONS: Hearing professionals should consider referring patients for a CICE when they meet the 60/60 guideline. It is hoped that provision of this guideline will result in greater numbers of adults being referred for CICEs, improving access to cochlear implants for patients who may benefit from this important technology.