Delirium is an acute and relatively sudden (developing over hours to days) decline in attention-focus, perception, and cognition. In medical usage it is not synonymous with drowsiness, and may occur without it. It is commonly associated with a disturbance of consciousness (eg, reduced clarity of awareness of the environment). The change in cognition (memory deficit, disorientation, language disturbance) or the development of a perceptual disturbance, must be one that is not better accounted for by a preexisting, established, or evolving dementia. Usually the rapidly fluctuating time course of delirium is used to help in the latter distinction.
Because it represents a change in cognitive function, the diagnosis cannot be made without knowledge of the affected person's baseline level of cognitive function.
The Obama fan base seem to be full of it. Delirious Change may not be the right change.