Power Spectral Analysis of Auditory Brain Stem Responses

Frequency Components as a Function of Stimulus Intensity and Stimulus Interval

Abstract

Spectral components of ABR as a function of stimulus intensity and stimulus interval were measured in 10 adults with normal hearing. At higher stimulus intensities, three peaks were observed at 0-100, 500 and 900Hz in the spectrum, of which the most prominent peak was around 100Hz. However, this dominancy of the low frequency components disappeared when the corresponding spectrum of spontaneous brain activities was subtracted from the response spectrum. With decrease of stimulus intensity, the power of all spectral components was regularly diminished. The power of low frequency spectral components up to 500Hz was kept unchanged with various stimulus intervals from 125ms to 11ms, while the power of higher frequency components tended to decrese with decreasing stimulus interval.