The impact of peripheral auditory nerve adaptation upon central measures of temporal integration in Nucleus 24 cochlear implant recipients

摘要

The objective of this study was to explore the relationship between peripheral neural adaptation and behavioral temporal integration in Nucleus 24 cochlear implant recipients. It was hypothesized that because the auditory nerve serves as the input to central temporal integrator, auditory nerve adaptation and temporal integration would be related. Specifically, the degree of adaptation observed at the level of the peripheral auditory system would be related to how well cochlear implant recipients integrated signal duration cues. A large amount of neural adaptation would result in relatively poor temporal integration.;Neural adaptation at suprathreshold levels was measured by tracking amplitude changes of the Electrical Compound Action Potential (ECAP) to 1000 pps biphasic pulse trains of varying durations. Temporal integration was assessed at suprathreshold levels through the use of a loudness balancing procedure and at threshold levels by measuring the effect of increased stimulus duration and stimulation rate on psychophysical detection thresholds. Varying degrees of neural adaptation and temporal integration were observed across individuals. However, correlation analyses revealed that the degree of neural adaptation had little influence upon temporal integration abilities in cochlear implant recipients. It was suggested that similar studies be conducted using a group of individuals with widely varying amounts of neural adaptation and/or temporal integration, and additionally, that neural adaptation and temporal integration be assessed at much faster rates of stimulation and at lower intensity levels than were used in this study.