July 16, 2012
Walking Ability Precursor To Alzheimer’s Disease
Lawrence LeBlond for redOrbit.com - Your Universe Online
A person´s walking patterns or ability to do so could be an early warning sign of cognitive decline and warrants advanced testing, according to researchers at a health conference on Sunday.
The findings are the result of three studies linking changes in walking ability to a weakening mental state, an early sign of dementia or Alzheimer´s disease. The findings were reported at the Alzheimer´s Association International Conference (AAIC) in Vancouver, Canada yesterday.
The findings are the first to make a physical connection to the disease, which previously required lengthy neurological exams and diagnoses. Experts say changes in a person´s walking patterns may occur well before cognitive decline surfaces. They noted that the evidence from the studies is “robust.”
The report, which came on the opening day of the week-long conference, follows a plan by the US government announced back in May that will help train doctors to detect earlier signs of Alzheimer´s and find a cure by 2025.
“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,” said Bill Thies, chief medical officer for the Alzheimer´s Association.
Alzheimer´s affects more than 5 million Americans and is expected to increase to 16 million by 2050 as the Baby Boomer generation ages.
In one of the studies, researchers, led by Dr. Stephanie Bridenbaugh from the Basel Mobility Center in Switzerland, tracked the walking abilities of nearly 1,200 elderly memory clinic outpatients and compared the results to the walking ability of healthy persons.
The results from the four-year study showed that a slowing pace and a change in gait was associated with progressed mental decline -- either mild cognitive impairment (MCI) or advanced Alzheimer´s disease.
“Those with Alzheimer's dementia walked slower than those with MCI, who in turn walked slower than those who were cognitively healthy,” explained Bridenbaugh in a news release issued by AAIC.
In the second study, researchers, led by Dr. Rodolfo Savica of the Mayo Clinic Study of Aging in Rochester, Minnesota, also looked at walking patterns among more than 1,300 patients over a 15-month period.
Their results showed that a decline in mental skills, including memory loss and executive function, were associated with a slowed walking pace and shortening of stride.
“Walking and movements require a perfect and simultaneous integration of multiple areas of the brain,” said Savica. “These results support a possible role of gait changes as an early predictor of cognitive impairment.”
Walking changes occur because the disease interferes with the circuitry between areas of brain. Savica ruled out other diseases, such as Parkinson´s and arthritis, as possible causes in his study findings.
In the third study, researchers from the Tohoku University Graduate School of Medicine in Sendai, Japan, followed 525 men and women 75 and older, conducting neurological, psychological and physical tests to assess the potential of a connection between gait and dementia.
In that study, led by Kenichi Meguro, the results mirrored both studies from Swiss and American researchers. Meguro´s team found that as walking abilities declined, so too did the mental skills of the patients.
“Gait velocity was significantly decreased as the severity of dementia symptoms increased,” Meguro noted in the new release. “Gait should no longer be considered a simple, automatic motor activity that is independent of cognition. They are linked.”
Lisa Silbert, a physician at Oregon Health and Science University in Portland, said that a single test might not work with everyone, however. “You´d be surprised how many people say to me 'He doesn´t walk that well at home' when I give them a gait test in the office,” she told Janice Lloyd at USA Today.
Silbert, who conducted a separate study on 19 dementia-free volunteers, measured gait speed during MRIs and gait speeds at home. She found that participants walked faster in the lab than they did at home. Slower in-home walking speed was associated with smaller total brain size. Dementia causes brain shrinkage, she noted.
The three studies reported at the AAIC may have uncovered a link between walking patterns and dementia, but did not prove a cause-and-effect connection.