Carl P. Browman

Diurnal periodicity of the human vertex potential.

Averaged auditory evoked potential waveforms were recorded from the vertex of human subjects 3, 9, and 15 hr. after awakening. Responses to pure tones of 60 and 80 dB SL were obtained at each session. Amplitude measures of N1–P2 and P2–N2 components were largest in the morning followed by a gradual attenuation across sessions. Waveform amplitude during the late evening ranged from 85% to 91% of the morning amplitude.

Tobacco use by narcoleptics and daytime sleep tendency

The nocturnal sleep and daytime sleep tendency were assessed in 10 narcoleptics who regularly smoked cigarettes and 10 narcoleptics who did not use tobacco. Standard sleep-wake polygraphic measures were recorded during the 24-h study. There were no statistical differences between groups in terms of nighttime sleep structure, although tobacco use resulted in a decreased sleep duration. Smokers tended to fall asleep more rapidly than non-smokers throughout daytime multiple sleep latency testing. The data failed to demonstrate a daytime arousal effect of tobacco for patients with narcolepsy.

Human auditory evoked potentials: Reliability of intensity functions

This investigation assessed the relative reliability of the human auditory evoked potential (AEP) amplitude-intensity and latency-intensity functions. Averaged AEP waveforms to 10 levels of stimulus magnitude were obtained from bipolar recordings. Variability and slope of group functions were constant, as indicated by nonsignificant differences in day-to-day residual variances and intersession regression coefficients. Periodic change in amplitude or latency thus indicated a shift of the entire function. Individual N1--P2 amplitude-intensity functions were similarly reliable, while individual P2--N2 amplitude and latency measures tended to be more variable. No significant differences were obtained across sessions for regression coefficients based on either group or individual data. Intersession AEP amplitude and latency apparently varied systematically with stimulus intensity.