Electrically Evoked Auditory Brainstem Response in Complete Cochlear Coverage

Abstract

The present study is focused to profile the Electrically Evoked Auditory Brainstem Response (EABR) along the length of the cochlea. Twenty children, implanted with Med-El Pulsar cochlear implants were randomly selected for the study. Electrically evoked auditory brainstem responses were recorded in all children at three different regions in the cochlea using 300CU, 500CU and 700CU with 30 micro second duration biphasic pulses through the cochlear implant. The stimulation rate used were, 34.1/s. Response profiling were done based on morphology of the waveform, amplitude of EABR peaks, Intensity-latency function and rate latency function with respect to the site of stimulation along the length of cochlea. EABR morphology and amplitude were better at apical region of cochlea. Latency changes with respect to site of stimulation in EABR are minimal. Good EABR amplitude represents better synchronous firing of nerve fibers. Appropriate stimulation through apical electrodes in cochlear implant will improve speech perception especially in the presence of noise.