Wrist actigraphic measures of sleep and rhythms.

With a piezo-electric activity transducer, wrist activity recordings were made simultaneously with EEG, EOG and EMG recordings. Wrist activity alone was used to estimate Total Sleep Time and blind independent scoring of sleep and wakefulness by EEG-EOG-EMG was done. Correlations between the two methods were termined for minutes of Sleep (r = 0.98), Total Sleep Period (r = 0.95) and minutes of Wake Time Within Sleep (r = 0.85). Continuous wrist activity recordings may thus provide inexpensive but very accurate estimates of Sleep Time.