An animal model for delirium.

This study describes an animal model for delirium comparing rats treated with either saline or atropine. The model was defined by recordings of cortical EEGs, maze performance, and behavioral observations. EEG slowing and increased amplitude, difficulty with attention and memory, sleep-wake cycle reversal, and changes in behavior (lack of focused direction, irritability, fluctuating levels of activity, excessive random sniffing) appeared consistent with signs and symptoms seen in human delirium. EEG abnormalities in atropine-treated rats returned to normal before cognitive deficits did. Motor activity monitoring did not reveal diminished motor activity as a confounding variable in maze performance.