1991 Volume 1991 Issue Supplement51 Pages 1-9
A computer program for automatic threshold detection of auditory steady state response (SSR) using a phase spectral analysis was developed. To estimate the usefulness of this automatic threshold detection program, auditory steady state response was examined on 15 adults with normal hearing while awake and during sleep. As an auditory stimulus,1000 Hz sinusoidally amplitude-modulated tone, with a modulation frequency of 40 Hz and a modulation depth of 95% was applied. When comparing SSR threshold while awake and during sleep, the threshold during sleep was higher than while awake in 8 subjects (53.3%) and the threshold during sleep was lower than that while awake in 2 subjects (13.3%). Differences between the threshold while awake and during sleep were less than 10 dB in 11 subjects (73.3%) and were 20 dB in the other 4 subjects (29.7%).
These findings suggested that the SSR thresholds during sleep are not so different from those while awake, and that the automatic SSR threshold detection using phase spectral analysis during sleep is as useful as while awake.
