Older people who suffer "mental lapses," or episodes when their thinking seems disorganized or illogical, may be more likely to develop Alzheimer's disease than people who do not have these lapses, according to a study published in the January 19, 2010, issue of Neurology.

These cognitive fluctuations, are common in a type of dementia called dementia with Lewy bodies, but researchers previously did not know how frequently they occurred in people with Alzheimer's disease and, equally important, what effect fluctuations might have on their thinking abilities or assessment scores.

The Neurology study involved 511 people with an average age of 78. Researchers interviewed the participant and a family member, evaluated the participants for dementia and tested their memory and thinking skills.

People with three or four of the following symptoms met the criteria for having mental lapses:

    * 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

Those with mental lapses were 4.6 times more likely to have dementia than those without mental lapses. People with mental lapses also tended to have more severe Alzheimer's symptoms and perform worse on tests of memory and thinking skills than people who did not have lapses.

"When older people are evaluated for problems with their thinking and memory, doctors should consider also assessing them for these mental lapses," said senior study author James E. Galvin, MD, MPH, of Washington University School of Medicine in St. Louis, who is a member of the American Academy of Neurology.



Citation: Escandon A, Al-Hammadi N, Galvin JE, ' Effect of cognitive fluctuation on neuropsychological performance in aging and dementia',  Neurology, Jan 2010, 74, 210-217