University of Iowa researchers are using EEG signals to predict and monitor for delirium and encephalopathy. Delirium, a sudden disruption of consciousness and cognition marked by vivid hallucinations, delusions and an inability to focus, affects 7 million hospitalized Americans annually. Researchers estimate that about 40 percent of delirium cases are preventable. Many cases are triggered by the care patients receive — especially large doses of anti-anxiety drugs and narcotics to which the elderly are sensitive — or the environments of hospitals themselves: busy, noisy, brightly lit places where sleep is constantly disrupted and staff changes frequently.