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Inconsistent Reaction Time Predicts Mortality

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Inconsistent performance in responding to a stimulus, rather than the speed with which one responds, is a marker of accelerated ageing and predicts mortality in older people, according to research published in PLoS ONE.

Scientists at the UNSW Centre for Healthy Brain Ageing measured the intraindividual variability of reaction times in older adults, and found that it predicted survival time after accounting for any signs of decline in cognitive functioning that may herald dementia.

Lead author Dr Nicole Kochan said the study was the first to comprehensively account for the effects of overall cognitive level and dementia on the relationship between mortality and variability of intraindividual reaction time. “Our findings suggest that greater intraindividual reaction time variability is a behavioural marker that uniquely predicts shorter time to death,” she said.

“Importantly, the predictive strength of intraindividual reaction time variability was virtually unchanged when we removed participants who developed dementia over the subsequent 8 years. This suggests that variability of reaction time is an independent risk factor and not simply a corollary of general cognitive decline or neuropathological disturbances associated with dementia.”

The study examined 861 community-dwelling participants aged 70–90 years over 8 years. Participants completed...

The full text of this article can be purchased from Informit.