An application of wavelet analysis to procedure of averaging waveform of 40-Hz auditory steady-state response

The auditory steady-state response (ASSR) is one of auditory evoked brain responses applied to objective audiometry test. ASSR evoked by an amplitude-modulated tone is recorded as a waveform with the same frequency as the stimulus modulation frequency. Since the 40-Hz ASSR can be measured when subjects are awake, a rapid objective audiometry test has been desired for the 40-Hz ASSR. In the previous paper, based on wavelet analysis, we proposed a design of procedure of averaging waveform of 40-Hz ASSR for our original objective audiometry device. In this paper, we present detail examination using complex continuous wavelet analysis of characteristics of brain waves obtained by our original objective audiometry device. We also propose a Meyer type band-pass filter to extract the waveform data of around 40 Hz. The effectiveness of band pass filter is shown by an experiment.