Faculty Bibliography

OBJECTIVE:To assess the safety of cochlear implants (CIs) in children under 9 months of age to better understand expected postoperative complication rates, and to provide a preliminary look at efficacy. STUDY DESIGN/METHODS:Single-center retrospective review. SETTING/METHODS:Tertiary referral center. PATIENTS/METHODS:Children 5 to 8 months of age who received a CI between 2011 and 2021. INTERVENTIONS/METHODS:Therapeutic-CI. MAIN OUTCOME MEASURES/METHODS:The primary outcome was 6-month postoperative complication rate. Secondary outcomes included length of stay, device explantation/reimplantation, rehabilitation supports, and hearing and language outcomes. Complications of children implanted under than 9 months of age was compared with a cohort of children implanted 9 to 18 months of age between the years 2011 and 2016 using a chi-squared test (p < 0.05). RESULTS:One hundred six children under 9 months of age were implanted (204 CIs) at a mean age of 6.6 months (range: 5-8). Postoperative complications occurred in 28 patients (26%) and were often minor. There were no mortalities. There was no statistically significant difference in complications, including reimplantation rates, between patients implanted under 9 months of age and those implanted 9 to 18 months of age. Speech discrimination outcomes were excellent, and mean spoken language outcomes were near normative for typically developing children. CONCLUSIONS:Cochlear implantation can be a safe and effective treatment option for children 5 to 8 months of age. Early hearing screening and referral for infants to receive appropriate intervention will continue to play a critical role in optimizing speech and language outcomes.

OBJECTIVES/OBJECTIVE:Single-sided deafness (SSD) can have consequences for a child's language, educational, and social development. A cochlear implant (CI) is the only device which can restore true binaural hearing, yet they are only approved for children with (SSD) over the age of five in the United States. Reports on speech perception outcomes for children implanted at a younger age are limited. The present study aims to examine the effects of age at implantation, duration of deafness, hearing loss etiology, and presence of additional disabilities on device usage and speech perception outcomes. METHODS:A retrospective chart review was used to examine demographics and speech perception outcomes for 18 children implanted at age five or younger. RESULTS:Speech perception results were highly variable, with some children deriving significant benefit and others demonstrating no sound awareness through the implant alone. Age at implantation and duration of deafness did not have a clear impact on outcomes. Device usage was low in many children, often those with anatomical abnormalities such as a hypoplastic cochlear nerve. There are challenges to assessing speech perception in young children with SSD, leading to a lack of standardized outcome measures. CONCLUSIONS:Early CI for children with SSD may improve speech perception, but benefit is not guaranteed. Candidacy evaluation should consider both medical and audiological factors, in addition to the degree of family support and realistic expectations. Caution is especially warranted in children with significant anatomical anomalies.

OBJECTIVE:Children with high-frequency severe-to-profound hearing loss and low-frequency residual hearing who do not derive significant benefit from hearing aids are now being considered for cochlear implantation. Previous research shows that hearing preservation is possible and may be desirable for the use of electroacoustic stimulation (EAS) in adults, but this topic remains underexplored in children. The goal of this study was to explore factors relating to hearing preservation, acceptance, and benefits of EAS for children. STUDY DESIGN:Retrospective review. SETTING:Tertiary academic medical center. PATIENTS:Forty children (48 ears) with preoperative low-frequency pure-tone averages of 75 dB HL or less at 250 and 500 Hz (n = 48). INTERVENTION:All patients underwent cochlear implantation with a standard-length electrode. MAIN OUTCOME MEASURE:Low-frequency audiometric thresholds, speech perception, and EAS usage were measured at initial stimulation, and 3 and 12 months postoperatively. Outcomes were compared between children with and without hearing preservation, and between EAS users and nonusers. RESULTS:Hearing was preserved at similar rates as adults but worse for children with an enlarged vestibular aqueduct. Fewer than half of children who qualified to use EAS chose to do so, citing a variety of audiologic and nonaudiologic reasons. No differences were detected in speech perception scores across the groups for words, sentences, or sentences in noise tests. CONCLUSIONS:Neither hearing preservation nor EAS use resulted in superior speech perception in children with preoperative residual hearing; rather, all children performed well after implantation.

INTRODUCTION/UNASSIGNED:Cochlear implants (CIs) provide access to sound for children and adults who do not receive adequate benefit from hearing aids. Age at implantation is known to affect outcomes across the lifespan. AREAS COVERED/UNASSIGNED:The effects of age on CI outcomes are examined for infants, children, adolescents, and older adults. A variety of outcome measures are considered, including speech perception, language, cognition, and quality of life measures. EXPERT OPINION/COMMENTARY/UNASSIGNED:For those meeting candidacy criteria, CIs are beneficial at any age. In general, younger age is related to greater benefit when considering pre-lingual deafness. Other factors such as additional disabilities, may mitigate this effect. Post-lingually deafened adults demonstrate similar benefit regardless of age, though the oldest individuals (80+) may see smaller degrees of improvement from preoperative scores. Benefit can be measured in many ways, and the areas of greatest benefit may vary based on age: young children appear to see the greatest effects of age at implantation on language measures, whereas scores on cognitive measures appear to be most impacted for the oldest population. Future research should consider implantation at extreme ages (5-9 months or > 90 years), unconventional measures of CI benefit including qualitative assessments, and longitudinal designs.

OBJECTIVE:To investigate a new surgical and signal processing technique that provides apical stimulation of the cochlea using a cochlear implant without extending the length of the electrode array. PATIENTS/METHODS:Three adult patients who underwent cochlear implantation using this new technique. INTERVENTIONS/METHODS:The patients received a cochlear implant. The surgery differed from the standard approach in that a ground electrode was placed in the cochlear helicotrema via an apical cochleostomy rather than in its typical location underneath the temporalis muscle. Clinical fitting was modified such that low frequencies were represented using the apically placed electrode as a ground. MAIN OUTCOME MEASURES/METHODS:Pitch scaling and speech recognition. RESULTS:All surgeries were successful with no complications. Pitch scaling demonstrated that use of the apically placed electrode as a ground lowered the perceived pitch of electric stimulation relative to monopolar stimulation. Speech understanding was improved compared with preoperative scores. CONCLUSIONS:The new surgical approach and clinical fitting are feasible. A lower pitch is perceived when using the apically placed electrode as a ground relative to stimulation using an extracochlear ground (i.e., monopolar mode), suggesting that stimulation can be provided more apically without the use of a longer electrode array. Further work is required to determine potential improvements in outcomes and optimal signal processing for the new approach.

AIM/UNASSIGNED:Untreated hearing loss is risk factor for dementia, depression and falls in the elderly population. The present study evaluated the outcomes of cochlear implantation in adults over age 85, including surgical outcomes, speech perception, and implant use. METHODS/UNASSIGNED:Retrospective chart review of 78 patients implanted at a tertiary academic medical center. Co-morbidities, pre-operative hearing thresholds and speech perception scores at 4 time points (pre-operative, and 3 months, 1, 2, and 3 years post-operatively) were collected from charts. Linear mixed models were used to account for missing data points. RESULTS/UNASSIGNED:Medical comorbidities such as hypertension (56%) and heart disease (53%) were common. Surgical complications were rare (5% or less) and minor. Local anesthesia was used for 71% of study patients implanted in the last three years. Significant improvements were seen for speech perception scores on monosyllabic words (37 percentage points), sentences in quiet (45 percentage points) and sentences in noise (28 percentage points). These improvements remained stable to at least two years post-activation. Seventy-one percent of patients wore their implant full time. CONCLUSION/UNASSIGNED:Cochlear implantation is safe and effective for very elderly adults. The use of local anesthesia may increase adoption of cochlear implantation and thus improve the quality of life for this population.

OBJECTIVE:To describe our experience with adults undergoing cochlear implantation (CI) for treatment of single-sided deafness (SSD). STUDY DESIGN/METHODS:Retrospective case review. SETTING/METHODS:Tertiary referral center. PATIENTS/METHODS:Fifty-three adults with SSD. INTERVENTIONS/METHODS:Unilateral CI. MAIN OUTCOME MEASURES/METHODS:Speech perception testing in quiet and noise, tinnitus suppression, and device usage from datalogs. RESULTS:The mean age at CI was 53.2 years (SD 11.9). The mean duration of deafness was 4.0 years (SD 7.8). The most common etiology was idiopathic sudden SNHL (50%). Word recognition improved from 8.7% (SD 15) preoperatively to 61.8% (SD 20) at a mean follow-up of 3.3 years (SD 1.8) (p < 0.0001). Adaptive speech recognition testing in the "binaural with CI" condition (speech directed toward the front and noise toward the normal hearing ear) revealed a significant improvement by 2.6-dB SNR compared to the preoperative unaided condition (p = 0.0002) and by 3.6-dB SNR compared to when a device to route sound to the contralateral side was used (p < 0.0001). Tinnitus suppression was reported to be complete in 23 patients (43%) and improved in 20 patients (38%) while the device was on. The addition of the CI did not lead to a decrement in hearing performance in any spatial configuration. Device usage averaged 8.7 (SD 3.7) hours/day. CONCLUSIONS:Cochlear implantation in adult SSD patients can suppress tinnitus and achieve speech perception outcomes comparable with CI in conventional candidates. Modest improvements in spatial hearing were also observed and primarily attributable to the head shadow effect. Careful patient selection and counseling regarding potential benefits are important to optimize outcomes.

The auditory system is sensitive to stimulus regularities such as frequently occurring sounds and sound combinations. Evidence of regularity detection can be seen in how neurons across the auditory network, from brainstem to cortex, respond to the statistical properties of the soundscape, and in the rapid learning of recurring patterns in their environment by children and adults. Although rapid auditory learning is presumed to involve functional changes to the auditory network, the chronology and directionality of changes are not well understood. To study the mechanisms by which this learning occurs, auditory brainstem and cortical activity was simultaneously recorded via electroencephalogram (EEG) while young adults listened to novel sound streams containing recurring patterns. Neurophysiological responses were compared between easier and harder learning conditions. Collectively, the behavioral and neurophysiological findings suggest that cortical and subcortical structures each provide distinct contributions to auditory pattern learning, but that cortical sensitivity to stimulus patterns likely precedes subcortical sensitivity.

Two notes sounded sequentially elicit melodic intervals and contours that form the basis of melody. Many previous studies have characterized pitch perception in cochlear implant (CI) users to be poor which may be due to the limited spectro-temporal resolution and/or spectral warping with electric hearing compared to acoustic hearing (AH). Poor pitch perception in CIs has been shown to distort melodic interval perception. To characterize this interval distortion, we recruited CI users with either normal (single sided deafness, SSD) or limited (bimodal) AH in the non-implanted ear. The contralateral AH allowed for a stable reference with which to compare melodic interval perception in the CI ear, within the same listener. Melodic interval perception was compared across acoustic and electric hearing in 9 CI listeners (4 bimodal and 5 SSD). Participants were asked to rank the size of a probe interval presented to the CI ear to a reference interval presented to the contralateral AH ear using a method of constant stimuli. Ipsilateral interval ranking was also measured within the AH ear to ensure that listeners understood the task and that interval ranking was stable and accurate within AH. Stimuli were delivered to the AH ear via headphones and to the CI ear via direct audio input (DAI) to participants' clinical processors. During testing, a reference and probe interval was presented and participants indicated which was larger. Ten comparisons for each reference-probe combination were presented. Psychometric functions were fit to the data to determine the probe interval size that matched the reference interval. Across all AH reference intervals, the mean matched CI interval was 1.74 times larger than the AH reference. However, there was great inter-subject variability. For some participants, CI interval distortion varied across different reference AH intervals; for others, CI interval distortion was constant. Within the AH ear, ipsilateral interval ranking was accurate, ensuring that participants understood the task. No significant differences in the patterns of results were observed between bimodal and SSD CI users. The present data show that much larger intervals were needed with the CI to match contralateral AH reference intervals. As such, input melodic patterns are likely to be perceived as frequency compressed and/or warped with electric hearing, with less variation among notes in the pattern. The high inter-subject variability in CI interval distortion suggests that CI signal processing should be optimized for individual CI users.

OBJECTIVES:There are many potential advantages to combined electric and acoustic stimulation (EAS) with a cochlear implant (CI), including benefits for hearing in noise, localization, frequency selectivity, and music enjoyment. However, performance on these outcome measures is variable, and the residual acoustic hearing may not be beneficial for all patients. As such, we propose a measure of spectral resolution that might be more predictive of the usefulness of the residual hearing than the audiogram alone. In the following experiments, we measured performance on spectral resolution and speech perception tasks in individuals with normal hearing (NH) using low-pass filters to simulate steeply sloping audiograms of typical EAS candidates and compared it with performance on these tasks for individuals with sensorineural hearing loss with similar audiometric configurations. Because listeners with NH had similar levels of audibility and bandwidth to listeners with hearing loss, differences between the groups could be attributed to distortions due to hearing loss. DESIGN:Listeners with NH (n = 12) and those with hearing loss (n = 23) with steeply sloping audiograms participated in this study. The group with hearing loss consisted of 7 EAS users, 14 hearing aid users, and 3 who did not use amplification in the test ear. Spectral resolution was measured with the spectral-temporal modulated ripple test (SMRT), and speech perception was measured with AzBio sentences in quiet and noise. Listeners with NH listened to stimuli through low-pass filters and at two levels (40 and 60 dBA) to simulate low and high audibility. Listeners with hearing loss listened to SMRT stimuli unaided at their most comfortable listening level and speech stimuli at 60 dBA. RESULTS:Results suggest that performance with SMRT is significantly worse for listeners with hearing loss than for listeners with NH and is not related to audibility. Performance on the speech perception task declined with decreasing frequency information for both listeners with NH and hearing loss. Significant correlations were observed between speech perception, SMRT scores, and mid-frequency audiometric thresholds for listeners with hearing loss. CONCLUSIONS:NH simulations describe a "best case scenario" for hearing loss where audibility is the only deficit. For listeners with hearing loss, the likely broadening of auditory filters, loss of cochlear nonlinearities, and possible cochlear dead regions may have contributed to distorted spectral resolution and thus deviations from the NH simulations. Measures of spectral resolution may capture an aspect of hearing loss not evident from the audiogram and be a useful tool for assessing the contributions of residual hearing post-cochlear implantation.