45-HOUR CONTINUOUS QUINTUPLE-SITE ACTIMETRY - RELATIONS BETWEEN TRUNKAND LIMB MOVEMENTS AND EFFECTS OF CIRCADIAN SLEEP-WAKE RHYTHMICITY

Diurnal and nocturnal trunk and limb motor activity of 20 healthy indi viduals was evaluated by actimetry for 45 consecutive hours. Sleep was assessed by sleep logs. Overall, motor activity significantly (p < .0 5) decreased in the order wrist, ankle, and trunk. There was significa ntly more motor activity in the dominant wrist during the diurnal peri od. Motor activity was significantly affected by the 24-hr sleep-wake cycle, with lower levels and prolonged immobility during the night. Ti me series analyses revealed different but significant correlations bet ween motor activity at all sites. These data imply that (a) motor acti vity should be recorded at the dominant wrist when the highest level o f motor activity is of importance, (b) recordings at the nondominant w rist are better indicators of trunk movement than are dominant wrist r ecordings, and (c) sites other than the conventional nondominant wrist recording site should be evaluated to improve the validity of motor a ctivity-based sleep-wake scoring.