In addition to the symptoms of delirium, the features include (1) autonomic hyperactivity, such as tachycardia, diaphoresis, fever, anxiety, insomnia, and hypertension; (2) perceptual distorsions, which are most frequently visual or tactile halucinations (visual hallucination; tactile hallucination) ; and (3) fluctuating levels of psychomotor activity, ranging from hyperexcitability to lethargy.