MONDAY, Jan. 18, 2010 (HealthDay News) -- Mental lapses among older adults occur more often among those developing Alzheimer's disease than healthy elders, new research finds.
Excessive daytime sleepiness, staring into space and disorganized or illogical thinking are other mental fluctuations that often precede Alzheimer's, say researchers from Washington University School of Medicine in St. Louis.
"For many years, people have jokingly attributed mental lapses, or incidents when the train of thought temporarily seems to jump its tracks, as 'senior moments,'" said lead researcher Dr. James Galvin, an associate professor of neurology. "It has never been clear as to whether these lapses could lead to the development of Alzheimer's disease.
"We demonstrate clearly, for the first time, that such episodes are more likely to occur in persons who are developing Alzheimer's disease," he said.
But this doesn't mean that everyone who has a "senior moment" is on the verge of dementia, Galvin stressed.
"While these lapses or fluctuations don't by themselves mean that you have Alzheimer's disease, 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," he said.
The study is published in the Jan. 19 issue of Neurology.
For the study, Galvin's team collected data on 511 seniors, average age 78, with memory problems. The researchers tested these adults with standard thinking and memory tests and also interviewed family members about their relative's daytime sleepiness, disorganized or illogical thinking, or episodes of staring into space for long periods. Three or four symptoms were seen in 12 percent of participants, indicating cognitive fluctuations.
People with those symptoms were 4.6 times more likely to be diagnosed with Alzheimer's and to have more severe Alzheimer's symptoms, Galvin's group found. They also performed worse on thinking and memory tests than people without these lapses.
Among 216 people diagnosed with very mild or mild dementia, 25 had mental lapses, while only two of the 295 without dementia had the fluctuations.
These mental lapses are common in a type of dementia called dementia with Lewy bodies -- the second most common cause of dementia after Alzheimer's disease, Galvin said. "But until recently we really did not know how frequently they occurred in people with Alzheimer's disease or what effect fluctuations might have on their thinking abilities," he said.
Cognitive fluctuations occur in Alzheimer's disease and can significantly affect clinical rating of the severity of dementia and performance on memory and thinking tests. Assessing these fluctuations should be considered in evaluating patients for cognitive disorders, Galvin said.
Experts had mixed views on the significance of the findings.
"It is commonly observed that some Alzheimer's disease patients can go through stages where they have apparent episodes of lucidity, when they can perform at much higher levels on 'good days,'" said Greg M. Cole, a neuroscientist at the Greater Los Angeles VA Healthcare System.
This suggests that the cellular and molecular machinery required for higher performance has not been entirely lost but is frequently suboptimal, he said. "I find this quite hopeful as it suggests therapeutics might evoke more of these good days or moments," said Cole, who is also associate director of the Alzheimer's Disease Research Center at the University of California Los Angeles David Geffen School of Medicine.
But another expert said the finding adds nothing new to the diagnosis of Alzheimer's disease.
Once many of these fluctuations start happening, "you are well on your way to dementia," said Dr. Gary Kennedy, director of geriatric psychiatry at Montefiore Medical Center in New York City.
The hope for improving the diagnosis and treatment of Alzheimer's hinges on finding physical markers that indicate disease progression and the effectiveness of treatment, another expert said.
"The finding is a terrific ad for the need for biomarkers in Alzheimer's disease," said William Thies, vice president for medical and scientific affairs at the Alzheimer's Association.
These mental fluctuations may be common, but are not an exact measurement of whether Alzheimer's disease is present or how far it has progressed, he said.
"We would like something better, something that has more precision, less variation," Thies said.
For more information on Alzheimer's disease, visit the Alzheimer's Association.