Body movement artifact as a contaminant in psychophysiological studies of sleep.

Abstract

ABSTRACTExperiments were undertaken to define the relationships between body movements and changes in oxygen consumption rate (V̇O2) and pulse rate. Methods included the use of indirect calorimetry for determination of V̇O2, a bedspring transducer and multiple electromyographic leads for movements, electrocardiograms for pulse rate, and electroencephalographic (EEG) recordings for condition of wakefulness or stage of sleep. Major and minor movements were distinguishable from each other in wakeful subjects by their effects on V̇O2 and pulse rate. Both types of movements evoked shorter changes during sleep. The concurrence of muscle potential or artifact on the EEG leads and polygraphic deflection from the bedspring was found to be a reliable indicator of movements eliciting such changes. Movements in sleep which evoked measureable changes in V̇O2 were noted to involve a considerable proportion of total muscle mass. V̇O2 response to movements during sleep endured for 1.52 min (S.D. ± 0.60), compared to 3.34 min (S.D. ± 0.99) in wakeful subjects. Pulse rate response was 0.26 min (S.D. ± 0.13) in wakeful subjects and appeared to be far briefer during sleep.