The Effect of Increasing Interphase Gap on N1 Latency of the Electrically Evoked Compound Action Potential and the Stimulation Level Offset in Human Cochlear Implant Users.

OBJECTIVE This study reports two potential biomarkers of the physiological status of the cochlear nerve (CN) in cochlear implant users. DESIGN This project represents a complementary analysis on a subset of electrophysiological data from our recently published study. This study compared changes in N1 latency and stimulation level (i.e., N1 latency offset and stimulation level offset) with increasing interphase gap of a biphasic pulse between children with cochlear nerve deficiency and children with normal-sized CNs. RESULTS Children with cochlear nerve deficiency showed smaller N1 latency offsets and larger stimulation level offsets than children with normal-sized CNs at all electrode locations tested. CONCLUSIONS The N1 latency and stimulation level offsets differ in two patient populations with different physiological statuses of the CN. These parameters may be useful for evaluating CN function in individual cochlear implant patients.