Changes in gait can be important early warning signs of cognitive decline, according to new research presented at the recent Alzheimer’s Association International Conference in Vancouver, British Columbia.
The studies on walking are significant as they indicate the first physical link to Alzheimer’s disease. Currently, the illness is detected based solely on signs of diminishing mental skills and the results of neurological tests and, in some cases, brain scans.
Five separate studies on the connection between cognitive decline and changes in walking — often apparent even before traditional symptoms of cognitive impairment are observable — were presented at the conference, adding up to what researchers called “robust” evidence of the link. The studies also raise the question of whether increased physical activity, such as aerobic exercise, may help ward off dementia.
Approximately 5.4 million Americans suffer from Alzheimer’s disease, a number expected to triple to about 16 million by 2050.
In one study, conducted by the Mayo Clinic, scientists used computer monitoring to track the stride length, cadence and speed of more than 1,300 adults during two visits roughly 15 months apart. The subjects also took part in cognitive tests, which showed that those who walked more slowly and with a shorter stride during their second visit also experienced larger declines in cognition, memory and executive function.
"Walking and movements require a perfect and simultaneous integration of multiple areas of the brain," Mayo Clinic researcher Rodolfo Savica told USA Today, noting that Alzheimer’s interferes with the connections among those areas.
"These changes support a possible role of gait changes as an early predictor of cognitive impairment," he said, adding that the changes in walking associated with cognitive decline were distinct from those that appear in patients suffering from Parkinson’s disease or arthritis.
A similar study of more than 1,100 elderly subjects in Basel, Switzerland, found that a person's gait became "slower and more variable as cognition decline progressed." About a quarter of the subjects had no signs of cognitive impairment. The others had either mild cognitive impairment or were in various stages of Alzheimer’s disease.
The participants took steps for researchers on a walkway equipped with 30,000 integrated sensors. First, they walked normally; then they walked while executing a cognitive task, such as counting backward by twos. People with a higher level of cognitive impairment walked more slowly or inconsistently than healthy subjects, but they had especially noticeable difficulty walking while performing the task.
The study indicates that testing patients in this manner could aid doctors by revealing “deficits you can’t see with the naked eye," Dr. Stephanie Bridenbaugh, who conducted the Swiss study, told The New York Times.
“A lot of times walking looked normal, even in people with moderate Alzheimer’s," she said, "but if you look at dual tasking, I can detect these problems.”
Tests Could Give Doctors New Tools for Alzheimer's Detection
The studies are part of a growing body of research on the connection between walking and cognitive health, which some experts say needs to become a more widely used diagnostic tool. “People who are focused on cognition largely never watch people move,” Dr. Stephanie Studenski, a geriatrician and walking expert at the University of Pittsburgh and the Pittsburgh Veterans Administration, told the Times. “The tests are all done sitting down. But damage to the wiring is an important, shared problem of difficulty with thinking and difficulty with moving.”
William Thies, the chief medical and scientific officer for the Alzheimer’s Association, told USA Today, “Monitoring deterioration and other changes in a person's gait is ideal because it doesn't require any expensive technology or take a lot of time to assess."
“If gait begins to deteriorate," Thies told the Times, "we begin to have a conversation about how is your memory.”
(MORE: Early Alzheimer's Detection: Is It Worth Knowing?)
“What we need is to use the information we have here and find a screening tool that physical therapists and doctors can use to red flag those who have a mobility problem,” Bridenbaugh told the Times. “This should be basic. When your patient is in your office and you listen to their heart, it should be basic to see how they walk.”
A Potentially Valuable New Treatment, and the Dangers of Binge Drinking
In other news from the Vancouver conference:
- A small trial of Gammagard, a drug currently used to treat immune disorders, found that it could also help slow the progress of Alzheimer's disease in patients for as long as three years, results that experts called "remarkable" given the usual steady progress of the disease.
- Two separate studies discovered stark cognitive risks for older moderate and binge drinkers. Adults 65 or older who reported binge drinking at least twice a month (defined as having four or more drinks in one sitting) were 2.5 times more likely to suffer cognitive and memory declines than their peers.
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