Stay active to keep a healthy mind in very old age

Oct 29 2012

By Sarah Guy, medwireNews Reporter

Poor physical performance, especially a slow walking speed, is significantly associated with dementia in individuals aged over 90 years, show study results.

"Our findings suggest that dementia is a complex neurodegenerative process that may affect physical performance and cognition," say Szofia Bullain and colleagues from the University of California in Irvine, USA.

In addition to slow walking speed, study participants who performed the worst in a chair stand-up task, balance task, and grip strength test were significantly more likely to have dementia than their counterparts who performed the best.

A total of 629 individuals from The 90+ Study, aged a median of 94 years, took part in the current research, completing a timed 4-m walk, five timed stands from a seated position, a 10-second standing balance test involving standing with one heel placed at the front of the other foot, and a grip strength test using weights.

The researchers adjusted all results for potential confounding factors including a history of cardiovascular or cerebrovascular disease, and level of education, which was higher than high school level for the majority of the cohort (72.5%).

The findings, published in the Archives of Neurology, show that participants who were unable to complete the walking test were a significant 29.7 times more likely to have dementia (diagnosed using the Diagnostic and Statistical Manual of Mental Disorders [Fourth Edition] criteria) than their peers who were in the top (fastest) quartile for that test.

"Gait requires a seamless coordination of several neurologic systems, including motor, sensory, and cerebellar activities, which may explain in part why it showed the strongest association with dementia," remark Bullain et al.

Each of the other tests also showed significant associations with dementia, with significant odds ratios of 15.6, 14.2, and 8.1 for the condition among those who were unable to complete the five chair stands, balance, and grip strength tests, respectively, compared with their counterparts in the top quartiles for performance on each test.

There are multiple possible explanations for the findings, remarks the research team, including that cognition may not deteriorate as rapidly as physical performance, or that decline in physical performance contributes to physical inactivity, which leads to decline in cognition.

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