The purpose of this study was to examine neural substrates of frequency change detection in cochlear implant (CI) recipients using the acoustic change complex (ACC), a type of cortical auditory evoked potential elicited by acoustic changes in an ongoing stimulus. A psychoacoustic test and electroencephalographic recording were administered in 12 postlingually deafened adult CI users. The stimuli were pure tones containing different magnitudes of upward frequency changes. Results showed that the frequency change detection threshold (FCDT) was 3.79% in the CI users, with a large variability. The ACC N1’ latency was significantly correlated with the FCDT and the clinically collected speech perception score. The results suggested that the ACC evoked by frequency changes can serve as a useful objective tool in assessing frequency change detection capability and predicting speech perception performance in CI users.

Audiologic testing found a strong likelihood that CIs did benefit our subset of Meniere's patients with severe to profound sensorineural hearing loss. Fluctuations in hearing sensitivity (perhaps owing to physical changes relative to the implant array with the spiral ganglion neurons during an acute attack or changes in spiral ganglion neurons because of the hydropic state) can often be resolved by subsequent reprogramming.

To describe the adaptive pattern of cortically generated auditory evoked potentials elicited by repeated stimuli via cochlear implants (CIs), the late auditory evoked potential (LAEP) was collected from nine postlingually deafened adult CI users. Tone bursts were presented in 30 trains consisting of 10 tone bursts each, with inter-stimulus intervals (ISIs) of 0.7 ms and inter-train intervals (ITIs) of 15s. The response to the first stimulus and the response to later tone bursts in the train were compared. Results showed that the LAEP for the first tone burst was larger than that for later tone bursts, displaying an adaptive pattern. This pattern appeared to be more prominent in CI users with good speech perception performance than in those with poorer performance. This finding is meaningful in the context of our future research to restore normal adaptation in CI users to improve their speech perception performance.

During our cochlear implant team's community outreach to African-Americans with hearing loss, we initiated several actions to address the various disparities in access to care and use of services: development of patient education, patient-run support group, tracking of clinical outcomes, and opportunities for involvement in health policy making for cochlear implants. Cochlear implant teams should deepen their involvement with African-Americans and other minorities with hearing loss to better support and ultimately improve cochlear implant access, performance, and function.

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