Delirium superimposed on dementia versus delirium in the absence of dementia: phenomenological differences.

OBJECTIVE

To examine differences in the phenomenological characteristics of delirium superimposed on dementia compared to those observed in delirious patients without dementia, based on the rating items of the Memorial Delirium Assessment Scale (MDAS).

METHODS

We conducted an analysis of a prospectively collected clinical delirium database utilized to record and monitor the care of delirious patients treated at Memorial Sloan-Kettering Cancer Center (MSKCC). Sociodemographic, medical variables, and MDAS total score and individual item ratings were analyzed in respect to differences between delirium in the demented (DD) versus delirium in the nondemented (ND).

RESULTS

We were able to examine data collected on 100 delirious patients: 82 ND patients and 18 DD patients. Patients in the DD group, compared to the ND group, had significantly greater levels of disturbance of consciousness and impairments in all cognitive domains (i.e., orientation, short term memory, concentration, organization of thought process). Severe symptoms were more common in the DD group compared to the ND group on all the MDAS cognitive items as well as in disturbance of consciousness. There were no significant differences between the DD and ND groups in terms of presence or severity of hallucinations, delusions, psychomotor behavior, and sleep-wake cycle disturbance.

SIGNIFICANCE OF RESULTS

Delirium superimposed on dementia has phenomenological differences compared to delirium in the absence of dementia. There are no significant differences in the severity of hallucinations, delusions, psychomotor behavior, or sleep-wake cycle disturbances. However, level of disturbance in consciousness (arousal and awareness) and impairments in multiple cognitive domains are significantly more severe in patients with delirium superimposed on dementia.