Slow walking speed in elderly associated with Alzheimer’s hallmarksDecember 28, 2015
How fast elderly people walk might be related to the amount of amyloid they have built up in their brains, even if they don’t yet have symptoms of Alzheimer’s disease, according to a new study.
Findings were published Dec. 7 on the website of Neurology, the medical journal of the American Academy of Neurology. The study involved 128 people with an average age of 76 who did not have dementia but were considered at high risk for developing it because they had some concerns about their memory. The participants had positron emission tomography scans of their brains to measure amyloid plaques in the brain. These plaques consist of dense deposits of a protein called beta amyloid, and their progressive buildup in the brain has been associated with the development of Alzheimer’s disease. Of the participants, 48% had a level of amyloid often associated with dementia.
Participants also were tested on thinking and memory skills and how well they could complete everyday activities. A total of 46% of the participants had mild cognitive impairment, which can be a precursor to the dementia that occurs in Alzheimer’s disease.
Walking speed was measured by timing people on how fast they could walk 4 meters (about 13 feet) at their usual pace. The average walking speed was 3.48 feet per second, results showed. All but two of the participants tested in the normal range of walking speed.
The researchers found an association between slow walking speed and amyloid in several areas of the brain, including the putamen, a key region involved in motor function. The researchers compared how fast people walked both with and without taking into account the amount of amyloid and found the amyloid level accounted for as much as 9% of the difference in walking speed.
The relationship between amyloid levels and walking speed did not change when researchers took into account participants’ ages, education levels or amount of memory problems.
“It’s possible that having subtle walking disturbances in addition to memory concerns may signal Alzheimer’s disease, even before people show any clinical symptoms,” study author Natalia del Campo, PhD, of the Gerontopole and the Centre of Excellence in Neurodegeneration of Toulouse (University Hospital Toulouse) in France, said in a news release.
Del Campo said the study looked only at a snapshot in time and does not prove that amyloid plaques cause the slowdown in walking speed; it shows the association. She added there are many other causes of slow walking in older adults.
The study was based on a larger trial called the Multidomain Alzheimer Preventive Trial, which was supported by the French Ministry of Health and Pierre Fabre Research Institute. The imaging was supported by Avid Radiopharmaceuticals/Eli Lilly and Company. Biological sample collection was supported by Exhonit Therapeutics. The promotion of the study was supported by the University Hospital in Toulouse.
Study abstract: http://www.neurology.org/content/early/2015/12/06/WNL.0000000000002235.short