July 18, 2011 (Paris) -- Falls may be an early sign of Alzheimer's disease, researchers report.
In a study of 125 older adults who appeared physically and cognitively healthy, two-thirds of those with large deposits of Alzheimer's-associated plaque in their brains suffered falls.
In contrast, only one-third of those with little or no plaque experienced falls.
"This is a really important finding. We didn't expect to see such a significant increase -- a doubling - of falls [in people with a lot of plaque]," says Susan Stark, PhD, of Washington University in St. Louis.
"To our knowledge, this is the first study to identify a risk of increased falls related to a diagnosis of preclinical Alzheimer’s disease," she tells WebMD.
Preclinical Alzheimer's disease is used to describe people with large deposits of Alzheimer's-associated plaque in their brains, despite appearing cognitively normal.
The findings were presented at the Alzheimer's Association International Conference 2011.
About 5.4 million Americans have Alzheimer's disease, 5.2 million of whom are 65 or older.
Falls are a leading cause of disability, premature nursing home placement, and death among older adults. Older people with Alzheimer's suffer more than double the rate of falls as people without the disorder, because of problems with balance, gait disorders, and visual and spatial perception, Stark says.
To determine whether falls are a harbinger of memory loss and other cognitive problems in people who will eventually develop full-blown Alzheimer's disease, the researchers recruited older volunteers who appeared to be cognitively healthy. Their average age was 65, and about two-thirds were female.
All underwent positron emission tomography (PET) scans to measure the amount of Alzheimer's-associated plaque in the brain.
Participants were given journals and asked to record the number of falls they had every month for eight months.
Thirty-six percent of volunteers who did not have large deposits of plaque in their brain suffered falls, a figure similar to that in the general population.
But among those who did have large deposits of plaque, the fall rate was about 66%, Stark says.
The analysis took into account factors that are known to raise the risk for falls, including years of education, age, number of medications, alcoholism, and ability to perform activities of daily living.