A psychophysiological study of the development of delirium in coronary care units.

This is a longitudinal investigation of the psychophysiological mechanism for the development of delirium in coronary care units (CCUs). Ten patients satisfying DSM-III-R diagnostic criteria for delirium (group D) and 10 controls (group C) were drawn from patients admitted to CCU. Electroencephalogram (EEG) and eye movement recordings were observed over the days that patients were admitted to CCU and on a control day of admission and compared for each group and between each day. In the D group, slowing of background EEG activity, particularly on day 2, and many R (rapid) group eye movements and RS type (rapid superimposed on slow) eye movements, particularly on day 3, were observed. That is, from days 2 to 3, EEG findings showed an improvement in consciousness, and eye movement recordings manifested signs of anxiety and tension. These psychophysiological findings can be used to explain the transition from prodromal delirium to obvious delirium, and are supported by clinical features.