Combining a lightweight telemetric mobility sensing system with nightly
EEG-sleep recordings, the authors obtained continuous monitoring of
rest-activity cycles among psychiatric patients hospitalized for primary
depression or acute schizophreniform thought disorder. The patients with
primary depression had a significantly higher percentage of their total
24-hour motor activity distributed during the night. Furthermore, this
increased nocturnal motor activity did not correlate significantly with
concurrent EEG-sleep measures of wakefulness. Indeed, the best predictors
of wakefulness were measures of daytime activity. This desynchronization of
sleep and nighttime motor activity in primary depression may explain the
need for combined pharmacotherapy in some severely depressed patients. The
authors suggest that expressing activity as a percentage distribution
function, rather than in terms of absolute amplitude, provides an objective
diagnostic index of depression.Abstract Teaser