The Australian researchers studied nearly 17,000 relatively healthy adults over the age of 65 who lived in Australia and the United States. They found that from 2010 to 2017, people who walked 5% or more slowly each year and showed signs of slower mental processing or cognitive function were more likely to develop dementia. The risk was higher in those with both gait and memory impairment.
These results highlight the importance of including gait speed in a dementia risk assessment and suggest that dual gait speed decline and memory measurement may be the best combination. As gait speed is fast and easy to measure, it could easily be incorporated into primary care or specialist visits.
Cause and effect
The scientists studied people over the age of 70 and Americans over the age of 65 for nearly seven years. The participants were asked to take cognitive tests that measured general cognitive decline, processing speed, memory, and verbal fluency every two years. They were also instructed to measure their ability to walk at least 3 meters twice every two years. They then took the two results and averaged them to determine the person’s typical walking speed.
The researchers found that the “dual declinersThose who declined in both cognition and gait speed over the life of the study had the highest risk of dementia. Gait decliners were defined as those who walked slower in 0.05 meters per second or more per year. Cognitive impairments performed the worst on cognitive tests year after year.
Not surprisingly, those with memory loss are at increased risk of dementia. However, the addition of gait speed (to memory decline) appears to increase this increased risk. The reason people with dual decline are at the highest risk for dementia could be that gait speed is capturing cognitive domains other than memory, such as executive functions.
Why could a slow speed indicate dementia?
There are a number of reasons why a slower walking pace over time could indicate early signs of dementia. For example, slow walking speed may be due to lack of physical activity, obesity or even diabeteswhich are risk factors for dementia.
Slowing down gait speed potentially captures the accumulation of chronic disease and its effect on the brain. Another reason could be that walking is a reflection of what is happening in the brain. if a pathology develops in the brain due to Alzheimer’s, Parkinson’s or dementiathis could manifest itself not only in cognitive functions such as poor memory, poor attention, or difficulty remembering things, but also in physical function.
Gait slowing is not only a marker of dementia, but also predicts other highly relevant outcomes such as frailty and disability.