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The hypothesis of this study was that broader patterns of physiological channel interactions in the local region of the cochlea are associated with poorer spectral resolution in the same region. Electrically evoked compound action potentials (ECAPs) were measured for three to six probe electrodes per subject to examine the channel interactions in different regions across the electrode array. To evaluate spectral resolution at a confined location within the cochlea, spectral-ripple discrimination (SRD) was measured using narrowband ripple stimuli with the bandwidth spanning five electrodes: Two electrodes apical and basal to the ECAP probe electrode. The relationship between the physiological channel interactions, spectral resolution in the local cochlear region, and vowel identification was evaluated. Results showed that (1) there was within- and across-subject variability in the widths of ECAP channel interaction functions and in narrowband SRD performance, (2) significant correlations were found between the widths of the ECAP functions and narrowband SRD thresholds, and between mean bandwidths of ECAP functions averaged across multiple probe electrodes and broadband SRD performance across subjects, and (3) the global spectral resolution reflecting the entire electrode array, not the local region, predicts vowel identification.

The neural dys-synchrony associated with auditory neuropathy spectrum disorder (ANSD) causes a temporal impairment that could degrade spatial hearing, particularly sound localization accuracy (SLA) and spatial release from masking (SRM). Unilateral cochlear implantation has become an accepted treatment for ANSD but treatment options for the contralateral ear remain controversial. We report spatial hearing measures in a child with ANSD before and after receiving a second cochlear implant (CI).An 11-year-7-month old boy with ANSD and expressive and receptive language delay received a second CI eight years after his first implant.The SLA and SRM were measured four months before sequential bilateral CIs (with the contralateral ear plugged and unplugged), and after nine months using both CIs.Testing done before the second CI, with the first CI alone, suggested that residual hearing in the contralateral ear contributed to sound localization accuracy, but not word recognition in quiet or noise. Nine-months after receiving a second CI, SLA improved by 12.76° and SRM increased to 3.8-4.2 dB relative to pre-operative performance. Results were compared to published outcomes for children with bilateral CIs.The addition of a second CI in this child with ANSD improved spatial hearing.

In the study described in the article, two children had their prescribed behind-the-ear (BTE) hearing aids retro-fit to become open-fit (OF) BTEs. One child, age 12y, had a bilateral, high-frequency, sensorineural hearing loss (BHFL), with normal hearing in the low frequencies. The other child, age 6y, had a bilateral, reverse-slope, sensorineural hearing loss (BRSL), with normal hearing in the high frequencies. Sound localization measurements were made at Day 1 unaided and with the OF-BTEs and 1 year post for both children. Both children spontaneously reported an immediate improvement in the quality of their own voice when first exposed to the OF-BTEs. Only the younger child showed immediate localization advantage over unaided when using the OF-BTEs. However, changes in localization accuracy over time were measured for both children that could be attributed to “relearning” to localize with a new acoustic coupling of the hearing aid to the ear. After using OF-BTE hearing aids for 1 year, both children, wh...