VARIATION OF BRAIN-STEM AUDITORY-EVOKED P OTENTIALS DURING ALL-NIGHT SLEEP INVESTIGATIONS

Continuous monitoring of brainstem auditory evoked potentials (BAEPs) was performed simultaneously with polysomnographic recording during no cturnal sleep in ten normal male subjects (mean age: 25,1 +/- 2,8 year s). Four channels of electroencephalogram, respiration (abdominal and thoracic), rectal temperature, electrocardiogram, electrooculogram, ch in electromyogram, and two channels of BAEPs were sampled by a multiva riable monitoring PC system and stored on an optical disk. All data ex cept BAEPs were preprocessed, integrated over thirty seconds and print ed on a single sheet. Sleep stage classification was done visually. BA EPs were analysed in the awake state and in different sleep stages. Th e results showed no significant changes in absolute latencies and inte rpeaklatencies I-III, III-V and I-V in correlation with different slee p stages. Insignificant BAEP alterations were found to be related to p hysiological temperature variations during the night. These changes sh owed an increase in latencies in connection with a decrease in body te mperature.