Accession Number : ADP006092

Title :   Psychophysiological Measures of Drowsiness as Estimators of Mental Fatigue and Performance Degradation during Sleep Deprivation,

Corporate Author : DEFENCE AND CIVIL INST OF ENVIRONMENTAL MEDICINE DOWNSVIEW (ONTARIO)

Personal Author(s) : Pigeau, R. A. ; Heslegrave, R. J. ; Angus, R. G.

Report Date : FEB 1988

Pagination or Media Count : 16

Abstract : This paper describes a methodology developed to measure 'drowsiness' electrophysiologically as an index of chronic fatigue experienced during periods of sleep loss. Nine volunteers performed continuous cognitive workload schedule with 15 min breaks occurring every 2 hrs throughout a 64 hr sleep deprivation experiment. To measure fatigue a 4 min eyes closed relaxation period was embedded one every hour within a battery of cognitive tasks. The subjects were instructed to relax with their eyes closed but remain awake and alert. At the end of this 4 min period, a bell sounded which cued the subjects to open their eyes and indicate their subjective level of drowsiness. EEG signals collected during these periods were both visually scored and computer quantified. Two raters visually scored the signals for: (1) time of first stage 1 sleep onset, (2) number of stage 1 sleep onsets, (3) shortest and longest time in stage 1 and (4) total amount of stage 1 sleep (or deeper). Period analysis was performed on the digitized data and a drowsiness scale was developed by subtracting the amount of theta and delta from alpha while controlling for individual differences by dividing the result by alpha minus theta minus delta activity present during baselines. (js)

Descriptors :   *MENTAL HEALTH, COGNITION, DEGRADATION, DIGITAL SYSTEMS, ELECTROENCEPHALOGRAPHY, EYE, FATIGUE, FATIGUE(PHYSIOLOGY), INDEXES, MEASUREMENT, SCHEDULING, SIGNALS, SLEEP DEPRIVATION, WORKLOAD.

Subject Categories : Psychology

Distribution Statement : APPROVED FOR PUBLIC RELEASE