Effect of high electrical stimulus intensities on the auditory nerve using brain stem response audiometry

Abstract

The response of the auditory nerve to acute intracochlear electrical stimulation using charge-balanced biphasic current pulses was monitored using electrically evoked auditory brain stem responses (EABRs). Stimulation at moderate charge densities (64 μC cm-2 geom/phase; 0.8 mA, 200 μs/phase) for periods of up to 12 hours produced only minimal short-term changes in the EABR. Stimulation at a high charge density (144 μC cm-2 geom/phase; 1.8 mA, 200 μs/phase) resulted in permanent reductions in the EABR for high stimulus rates (> 200 pulses per second [pps]) or long stimulus durations (12 hours). At lower stimulus rates and durations, recovery to prestimulus levels was slow but complete. The me..