Physical frailty linked to dementia pathology

NEW YORK (Reuters Health) - Physical weakness or "frailty" among elderly people can be an early indicator of the presence of abnormal brain plaque and tangles characteristic of Alzheimer's disease, even before the onset of memory problems, a new study hints.

The degree of Alzheimer disease "pathology" in older patients with and without dementia is directly associated with their degree of physical frailty, researchers report in the August 12th issue of the medical journal Neurology.

Dr. Aron S. Buchman, from Rush University Medical Center in Chicago and colleagues examined the brains of 165 people in their 80s who had died while participating in a long-term study called the Rush Memory and Aging Project.

While the participants were alive, they were tested yearly for signs of physical frailty using tests of grip strength, time to walk 8 feet, body composition and tiredness. Results of these tests were used to generate a "frailty score."

The investigators found that the level of frailty was approximately two times higher in a person with a high level of Alzheimer disease brain pathology compared with a person with a low level of Alzheimer disease pathology.

Thirty-six percent of the study group had dementia, or showed signs of memory loss. "Interestingly," Buchman said, physical frailty was tied to Alzheimer disease brain pathology in older persons both with and without dementia.

"These findings raise the possibility that Alzheimer's disease may contribute to frailty or that frailty and Alzheimer's disease share a common cause," Buchman said.

"We theorize that the accumulation of these plaques and tangles in the brain could affect the areas of the brain responsible for motor skills and simple movements years before the development of dementia," the researcher added.

Studies show that about seven percent of people older than age 65 are considered frail; that number jumps to 45 percent after age 85.

SOURCE: Neurology, August 12, 2008.