Mental processing and walking speeds both slow before dementia – but which slows first?

2 April, 2015 in subject Okategoriserade

A decline in walking speed can predict dementia, as can a decline in our ability to perform familiar tasks rapidly and with ease, a skill known as mental processing. New research from ARC suggests that a reduction in processing speed precedes a reduction in walking speed. This finding improves our understanding of who should be monitored to prevent both future cognitive decline and physical problems such as falls.
Researchers have long known that poor physical function, including reduced walking speed, predicts dementia. More recently, changes in physical functioning have been linked to changes in overall mental ability. Specifically, a decline in processing speed has been tied to a decline in walking speed. Until now, though, there was no evidence about which ability began to decline first.
Led by researcher and physical therapist Anna-Karin Welmer, a group of ARC scientists set out to look more closely at the relationship between walking speed, processing speed, and dementia over time. They used information from the Swedish National study on Aging and Care – Kungsholmen, a study of people 60 years and older in central Stockholm, Sweden, who have been followed up by researchers since 2001.
Participants 78 years and younger were examined every six years, and those who were older, every three years. Trained nurses checked walking speed. Psychologists gave participants a battery of tests to assess processing speed, and physicians measured participants’ global mental function and diagnosed dementia. Welmer and her colleagues analyzed the data, adjusting their results for other things that can affect walking speed, including demographic factors, stroke, and pain.
They found that slower walking speed at baseline and decline in walking speed over time both predicted dementia. Walking speed, processing speed, and global cognition all declined much more over time in those who developed dementia than in those who did not. The decline in processing speed preceded the decline in walking speed, which suggests that slower processing speed is may be linked to the slowdown in walking that precedes dementia.
The study gives health care professionals and others who work with older people a new factor, in addition to walking speed, which may help predict who may develop dementia – a simple test of processing speed. But Anna-Karin Welmer stresses that tests of walking speed remain important in clinical settings, such as primary health care.
“Checking how fast someone walks and then seeing if this changes over time is so simple, but it tells you a lot about the health of a person,” she says.
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