“Physicians and nurses often don’t know about it,” added Inouye, who directs the Aging Brain Center at Hebrew Senior Life, a Harvard affiliate that provides elder care and conducts gerontology research.
Preventing delirium is crucial, she said, because “there still aren’t good treatments for it once it occurs.” Researchers estimate that about 40 percent of delirium cases are preventable.
Vivid flashbacks “They go home and don’t have the language to describe what has happened to them,” said Jackson, adding that such incidents are often mistaken for psychosis or dementia.
“Some patients have very striking delusional memories that are very clear distortions of what happened: patients who were catheterized who think they were sexually assaulted and patients undergoing MRIs convinced that they were fed into a giant oven.” Some hospitals are moving to prevent delirium through a more careful use of medications, particularly tranquilizers used to treat anxiety called benzodiazepines, which are known to trigger or exacerbate the problem.
While delirium and dementia can coexist, they are distinctly different illnesses.
Dementia develops gradually and worsens progressively, while delirium occurs suddenly and typically fluctuates during the course of a day.
A year after discharge, 80 percent of 821 ICU patients ages 18 to 99 scored lower on cognitive tests than their age and education would have predicted, while nearly two-thirds had scores similar to patients with traumatic brain injury or mild Alzheimer’s disease.