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Drowsiness, Staring May Signal Alzheimer’s

Study: Staring Off Into Space, Drowsiness, Other Mental Lapses May Be Early Alzheimer’s Symptoms
WebMD Health News
Reviewed by Louise Chang, MD

Jan. 19, 2010 -- Drowsiness, staring off into space, or losing your train of thought may be early symptoms of Alzheimer’s disease, according to a new study.

Researchers found that people with at least three different symptoms of mental lapses like these were 4.6 times more likely to have dementia than people without such episodes. In addition, people with mental lapses tended to have more severe Alzheimer’s symptoms and perform worse on memory and thinking tests.

"If you have these lapses, they don't by themselves mean that you have Alzheimer's," researcher James Galvin, MD, a Washington University neurologist at Barnes-Jewish Hospital in St. Louis, says in a news release. "Such lapses do occur in healthy older adults. But our results suggest that they are something your doctor needs to consider if he or she is evaluating you for problems with thinking and memory."

Previous studies have linked mental lapses with another type of dementia known as dementia with Lewy bodies, but their association with Alzheimer’s disease has been unknown.

Lewy body dementia causes clumps of proteins known as Lewy bodies to form in neurons and is the most common form of dementia after Alzheimer’s disease. It can overlap with Alzheimer’s disease as well as Parkinson’s disease.

New Alzheimer’s Symptoms?

In the study, published in Neurology, researchers evaluated 511 older adults (average age 78) for Alzheimer’s disease and dementia. They also interviewed participants and a family member for signs of mental lapses.

Researchers found that 12% of the participants met the criteria for having mental lapses by having at least three of the following symptoms:

  • Feeling drowsy or lethargic all the time or several times per day despite getting enough sleep the night before
  • Sleeping two or more hours before 7 p.m.
  • Having times when the person’s flow of ideas seems disorganized, unclear, or not logical
  • Staring into space for long periods

The study showed that people with three or four symptoms of mental lapses were nearly 4.6 times more likely to be diagnosed with Alzheimer’s.

In addition, of the 216 diagnosed with very mild or mild dementia, 25 had mental lapses compared with only two of the 295 without any signs of dementia.

"We have some ideas about why the biology of dementia with Lewy bodies causes these mental lapses, but nothing comparable for Alzheimer's," Galvin says. "It's possible that some of the patients who were diagnosed with Alzheimer's disease in this study will go on to develop dementia with Lewy bodies, but at the time of the study, they weren't showing any of the Lewy body dementia's core features."

Researchers say more study is needed to determine whether to include mental lapses in diagnostic tests for Alzheimer’s disease.

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