Actigraphy and insomnia: a closer look. Part 1

In recent years, wrist actigraphy has been scrutinized as a possible supplement to or even replacement for other methods traditionally used to assess the sleep of clinical patients and research subjects. While showing promise for some applications, its accuracy in measuring the nocturnal sleep of insomniacs remains in question. A reexamination of the relevant data indicates that with respect to estimating the total sleep time of insomnia patients, use of the actigraph does not yield significantly lower error than daily sleep logs and predicts only about a third of the variance. However, the actigraph does show some potential for assessing the night-to-night variability of a given individual's sleep, suggesting that it may be most useful for assessing longitudinal changes within a treatment program or experimental protocol.