Although this might sound very scary to an older person who is unsteady on his feet, it's actually good news, researchers say.
"The last thing I want to do is create a panic about walking slower," says Dr. Joe Verghese, assistant professor of neurology at Albert Einstein College of Medicine and lead author of a report on the finding, which appears in tomorrow's issue of the New England Journal of Medicine."Lots of people have difficulty walking when they get older, and 60 or 70 percent of the time it is caused by things like arthritis or back trouble," he adds."
The study didn't look at people with walking problems caused by arthritis. But other kinds of abnormal gait are warning signs of vascular dementia, which does not get the name recognition of Alzheimer's disease, the major cause of dementia in the aging, but does account for 30 percent of cases, Verghese says.
Gait problems included marked swaying, balance trouble, the inability to walk heel-to-toe, short steps, shuffling, not swinging the arms, and difficulty making turns.
"The surprise was how strong a predictor [abnormal gait] was and how it predicted into the future, at least 10 years into the future," Verghese says.
And that is good news because vascular dementia is potentially preventable. It results from diminished flow of blood to the brain, and measures can be taken to keep blood flow at a normal level -- "better control of blood pressure, better control of cholesterol," Verghese says.
The finding comes from the Einstein Aging Study, which has followed a large number of older people for more than two decades. This part of the study looked at 422 individuals between the ages of 75 and 85, whose gait was evaluated when they enrolled in the study. In a follow-up period averaging 6.6 years, 70 of the participants developed Alzheimer's disease and 47 developed vascular dementia. The people with neurological gait disorders had more than three times the risk of vascular dementia than those with normal gaits, although their risk of Alzheimer's disease was not affected.
It was known when the study began that an older person with dementia who had difficulty walking was more likely to have the vascular form, says Dr. Richard Lipton, the Lotti and Bernard Benson Faculty Scholar in Alzheimer's Disease at Einstein, who heads the aging study.
"What wasn't known previously, that this predicted the future development of vascular dementia, even a decade before diagnosis," he says.
Lipton sees the discovery as part of "a really fantastic shift in the field in the past two decades, from the view that dementia is not treatable. Two decades ago, the hope was finding the 10 percent of cases that might be treatable," he says.
"Today, we have three approved drugs for Alzheimer's disease, and some are also effective for vascular dementia. Already the condition has shifted from being rarely treatable to being almost always treatable," he adds.
The next transition, Lipton says, "is to make these conditions preventable. Treatment today does slow progression but is not fully curative."
Several preventive trials are under way, using a variety of drugs, ranging from estrogens to nonsteroidal anti-inflammatory drugs, Lipton says, "and the key to developing preventive intervention is to develop robust methods of identifying people at high risk."
The finding that an abnormal walking pattern can be a long-term warning of dementia can help doctors start preventive therapy early, he says.
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