Variables Affecting Cochlear Implant Performance After Loss of Residual Hearing.

OBJECTIVE: Determine variables that influence post-activation performance for cochlear implant (CI) recipients who lost low-frequency acoustic hearing. METHODS: A retrospective review evaluated CNC word recognition for adults with normal to moderately severe low-frequency hearing (preoperative unaided thresholds of ≤70 dB HL at 250 Hz) who were implanted between 2012 and 2021 at a tertiary academic center, lost functional acoustic hearing, and were fit with a CI-alone device. Performance scores were queried from the 1, 3, 6, 12, and 24-month post-activation visits. A linear mixed model evaluated the effects of age at implantation, array length (long vs. mid/short), and preoperative low-frequency hearing (normal to mild, moderate, and moderately severe) on speech recognition with a CI alone. RESULTS: 113 patients met the inclusion criteria. There was a significant main effect of interval (p < 0.001), indicating improved word recognition post-activation despite loss of residual hearing. There were significant main effects of age (p = 0.029) and array length (p = 0.038), with no effect of preoperative low-frequency hearing (p = 0.171). There was a significant 2-way interaction between age and array length (p = 0.018), indicating that older adults with mid/short arrays performed more poorly than younger adults with long lateral wall arrays when functional acoustic hearing was lost. CONCLUSION: CI recipients with preoperative functional low-frequency hearing experience a significant improvement in speech recognition with a CI alone as compared to preoperative performance-despite the loss of low-frequency hearing. Age and electrode array length may play a role in post-activation performance. These data have implications for the preoperative counseling and device selection for hearing preservation candidates. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:1868-1873, 2024.

Demographic Representation in Clinical Research Relative to a Cochlear Implant Patient Population.

OBJECTIVES: Research samples that are representative of patient populations are needed to ensure the generalizability of study findings. The primary aim was to assess the efficacy of a study design and recruitment strategy in obtaining a participant sample that was representative of the broader cochlear implant (CI) patient population at the CI center. A secondary aim was to review whether the CI recipient population was representative of the state population. METHODS: Demographic variables were compared for a research participant sample (n = 79) and the CI patient population (n = 338). The participant sample was recruited from the CI patient population. The study design included visits that were at the same location and frequency as the recommended clinical follow-up intervals. The demographics for the combined group (participant sample and patient population) were then compared to the reported demographics for the population in North Carolina. RESULTS: There were no significant differences between the participant sample and patient population for biological sex, age at implantation, racial distribution, socioeconomic position, degree of urbanization, or drive time to the CI center (p ≥ 0.086). The combined CI recipient population was significantly different from the North Carolina population for the distributions of race, ethnicity, and degree of urbanization (p < 0.001). CONCLUSION: The study design and recruitment strategy allowed for recruitment of a participant sample that was representative of the CI patient population. Disparities in access to cochlear implantation persist, as supported by the significant differences in the combined CI recipient population and the population for our state. LEVEL OF EVIDENCE: 3 Laryngoscope, 2024.

Hearing health care access for adult cochlear implant candidates and recipients: Travel time and socioeconomic status.

Objectives: Access to cochlear implantation may be negatively influenced by extended travel time to a cochlear implant (CI) center or lower socioeconomic status (SES) for the individual. There is a critical need to understand the influence of these variables on patient appointment attendance for candidacy evaluations, and CI recipients' adherence to post-activation follow-up recommendations that support optimal outcomes. Methods: A retrospective chart review of adult patients referred to a CI center in North Carolina for initial cochlear implantation candidacy evaluation between April 2017 and July 2019 was conducted. Demographic and audiologic data were collected for each patient. Travel time was determined using geocoding. SES was proxied using ZCTA-level Social Deprivation Index (SDI) information. Independent samples t tests compared variables between those who did and did not attend the candidacy evaluation. Pearson correlations assessed the association of these variables and the duration of time between initial CI activation and return for first follow-up visit. Results: Three hundred and ninety patients met the inclusion criteria. There was a statistically significant difference between SDI of those who attended their candidacy evaluation versus those who did not. Age at referral or travel time did not show statistical significance between these two groups. There was no significant correlation with age at referral, travel time, or SDI with the duration of time (days) between initial activation and the 1-month follow-up. Conclusions: Our findings suggest that SES may influence a patient's ability to attend a cochlear implantation candidacy evaluation appointment and may further impact the decision to pursue cochlear implantation.Level of evidence: 4 - Case Series.

Incidence of Cochlear Implant Electrode Contacts in the Functional Acoustic Hearing Region and the Influence on Speech Recognition with Electric-Acoustic Stimulation.

OBJECTIVES: To investigate the incidence of electrode contacts within the functional acoustic hearing region in cochlear implant (CI) recipients and to assess its influence on speech recognition for electric-acoustic stimulation (EAS) users. STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. PATIENTS: One hundred five CI recipients with functional acoustic hearing preservation (≤80 dB HL at 250 Hz). INTERVENTIONS: Cochlear implantation with a 24-, 28-, or 31.5-mm lateral wall electrode array. MAIN OUTCOME MEASURES: Angular insertion depth (AID) of individual contacts was determined from imaging. Unaided acoustic thresholds and AID were used to calculate the proximity of contacts to the functional acoustic hearing region. The association between proximity values and speech recognition in quiet and noise for EAS users at 6 months postactivation was reviewed. RESULTS: Sixty percent of cases had one or more contacts within the functional acoustic hearing region. Proximity was not significantly associated with speech recognition in quiet. Better performance in noise was observed for cases with close correspondence between the most apical contact and the upper edge of residual hearing, with poorer results for increasing proximity values in either the basal or apical direction ( r14 = 0.48, p = 0.043; r18 = -0.41, p = 0.045, respectively). CONCLUSION: There was a high incidence of electrode contacts within the functional acoustic hearing region, which is not accounted for with default mapping procedures. The variability in outcomes across EAS users with default maps may be due in part to electric-on-acoustic interference, electric frequency-to-place mismatch, and/or failure to stimulate regions intermediate between the most apical electrode contact and the functional acoustic hearing region.

Influence of Electric Frequency-to-Place Mismatches on the Early Speech Recognition Outcomes for Electric-Acoustic Stimulation Users.

PURPOSE: Cochlear implant (CI) recipients with hearing preservation experience significant improvements in speech recognition with electric-acoustic stimulation (EAS) as compared to with a CI alone, although outcomes across EAS users vary. The individual differences in performance may be due in part to default mapping procedures, which result in electric frequency-to-place mismatches for the majority of EAS users. This study assessed the influence of electric mismatches on the early speech recognition for EAS users. METHOD: Twenty-one participants were randomized at EAS activation to listen exclusively with a default or place-based map. For both groups, the unaided thresholds determined the acoustic cutoff frequency (i.e., > 65 dB HL). For default maps, the electric filter frequencies were assigned to avoid spectral gaps in frequency information but created varying magnitudes of mismatches. For place-based maps, the electric filter frequencies were assigned to avoid frequency-to-place mismatches. Recognition of consonant-nucleus-consonant words and vowels was assessed at activation and 1, 3, and 6 months postactivation. RESULTS: For participants with default maps, electric mismatch at 1500 Hz ranged from 2 to -12.0 semitones (Mdn = -5 semitones). Poorer performance was observed for those with larger magnitudes of electric mismatch. This effect was observed through 6 months of EAS listening experience. CONCLUSIONS: The present sample of EAS users experienced better initial performance when electric mismatches were small or eliminated. These data suggest the utility of methods that reduce electric mismatches, such as place-based mapping procedures. Investigation is ongoing to determine whether these differences persist with long-term EAS use. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.22096523.

Masked Speech Recognition as a Function of Masker Location for Cochlear Implant Users With Single-Sided Deafness.

PURPOSE: Cochlear implant (CI) recipients with normal or near normal hearing (NH) in the contralateral ear, referred to as single-sided deafness (SSD), experience significantly better speech recognition in noise with their CI than without it, although reported outcomes vary. One possible explanation for differences in outcomes across studies could be differences in the spatial configurations used to assess performance. This study compared speech recognition for different spatial configurations of the target and masker, with test materials used clinically. METHOD: Sixteen CI users with SSD completed tasks of masked speech recognition presented in five spatial configurations. The target speech was presented from the front speaker (0° azimuth). The masker was located either 90° or 45° toward the CI-ear or NH-ear or colocated with the target. Materials were the AzBio sentences in a 10-talker masker and the Bamford-Kowal-Bench Speech-in-Noise test (BKB-SIN; four-talker masker). Spatial release from masking (SRM) was computed as the benefit associated with spatial separation relative to the colocated condition. RESULTS: Performance was significantly better when the masker was separated toward the CI-ear as compared to colocated. No benefit was observed for spatial separations toward the NH-ear. The magnitude of SRM for spatial separations toward the CI-ear was similar for 45° and 90° when tested with the AzBio sentences, but a larger benefit was observed for 90° as compared to 45° for the BKB-SIN. CONCLUSIONS: Masked speech recognition in CI users with SSD varies as a function of the spatial configuration of the target and masker. Results supported an expansion of the clinical test battery at the study site to assess binaural hearing abilities for CI candidates and recipients with SSD. The revised test battery presents the target from the front speaker and the masker colocated with the target, 90° toward the CI-ear, or 90° toward the NH-ear.