The psychophysiological basis of delirium

Abstract

To clarify the pathophysiology of delirium, various psychophysiological studies on delirium were reviewed. In brain structure studies by computed tomography (CT) and magnetic resonance imaging (MRI), cerebrocortical atrophy, areas of white matter hyperintensity, and lesions of the basal nucleus were found in delirious patients. In terms of brain function, single photon emission computed tomography (SPECT) showed that brain blood flow was decreased in the prefrontal lobe and increased in the striatum and infratemporal lobe, or decreased in the thalamus and basal nucleus of delirious patients. With electroencephalography (EEG), slowing in the posterior dominant rhythm and generalized theta or delta slow-wave activity were recognized in delirious patients. Inspection combining EEG and ocular movements in hyperactive delirium patients showed characteristic low amplitude and slowing in background EEG activity and RS-type eye movements comprising rapid movements juxtaposed over slow movements. Hypoactive delirium is frequently recognized in cancer patients, in addition to hyperactive delirium. The pathophysiology of whole delirium may thus be elucidated if delirium studies for cancer patients are performed using psychophysiological methods.