Delirium Spurs Alzheimer’s Decline

March 25, 2013

People with Alzheimer’s who are hospitalized often develop delirium, a period of acute disorientation that may last for days. Now, in the longest-running study of its type, researchers found that people with Alzheimer’s who develop delirium may show an accelerated decline in their memory and thinking skills for at least five years after hospitalization.

Earlier studies had shown that delirium may lead to worsening of cognitive skills in those with Alzheimer’s. This study highlights how the effects of delirium may be long-lasting and underlines the importance of avoiding hospitalization and other triggers of delirium whenever possible in anyone with dementia.

For the study, published in the Archives of Internal Medicine, researchers at Hebrew SeniorLife, an affiliate of Harvard Medical School, analyzed data from 263 men and women with Alzheimer’s disease who had been hospitalized for a variety of medical concerns, including falls and heart troubles. They found that 56 percent of them developed delirium during their hospital stay.

Before the hospitalization, all the patients showed similar rates of decline in thinking and memory skills. But after the hospital stay, those who developed delirium had more than twice the cognitive deterioration in the year following hospitalization as those who didn’t suffer delirium.

The more rapid decline in mental skills persisted for at least five-years following the episode of delirium. The researchers controlled for factors like other medical illnesses, the original severity of dementia and age that might have contributed to the mental deterioration.

Delirium is usually thought of as a temporary condition lasting up to a few days, in which patients seem “out of it” and are unable to focus. Nurses and doctors do not always recognize delirium in people with Alzheimer’s disease, who may already be showing some signs of disorientation. “But our research suggests it is an important medical problem,” said Alden Gross, the lead author of the study.

Strategies to treat delirium when it occurs are still being studied. But it may be more important to prevent it from occurring in the first place, the authors note, especially in those with dementia.

Proven measures to prevent delirium include making sure patients are accommodated with measures to improve mobility as well as good nutrition, proper hydration and getting enough sleep. In addition, it is also important that patients do not get inappropriate medications, which can increase the likelihood of delirium. Finally, environmental factors such as making sure there is light in the room during the day and dark at night and having large clocks in the room can be helpful, she added.

In addition, a visit to the hospital can be particularly disorienting for someone with Alzheimer’s disease, who may have an especially difficult time adjusting to strange surroundings, interruption of routines and a bustle of activity. Though people with Alzheimer’s of course may need hospitalization for some medical concerns, keeping hospital visits to a minimum also may be important for preventing the onset of delirium.

“Strategies to prevent delirium may represent a promising avenue to explore for ameliorating cognitive deterioration in Alzheimer’s,” the authors conclude.

By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by William J. Netzer, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.

Source: Alden L. Gross, Richard N. Jones, Daniel A. Habtermariam, et al: “Delirium and Long-Term Cognitive Trajectory Among Persons With Dementia.” Archives of Internal Medicine, August 2012.


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