Power spectral analysis of auditory slow vertex responses of five normal hearing adults was carried out. Analysis time is 512 msec and 1024 msec.
Results:
1, When acoustic stimuli were perceived, the power spectra of 3-9c/s at 512 msec analysis time were higher than at 1024 msec analysis time, and when acoustic stimuli were not perceived, there were little differences between the two analysis times.,
2. The power spectra at 512 msec analysis time, 10 dB stimuli were high at 4-9 c/s, with a peak at 4-5 c/s.
3. The sum of power spectra of 3 c/s to 9 c/s at 1024 msec analysis time showed clear difference between auditory evoked responses and spontaneous brain activity. The sum at stimulations increased with stimulus intensity.
4, The sum of power spectra of 4 c/s to 9 c/s at 512 msec analysis time, showed clearer difference between auditory evoked responses and spontaneous brain activity than at 1024 msec analysis time.