Gait Speed Under Varied Challenges and Cognitive Decline in Older Persons
Objective: to examine whether usual gait speed, fast gait speed or speed while walking with a cognitive or neuromuscular challenge predicts evolving cognitive decline over 3 years.
Design: prospective study.
Setting: population-based sample of community-dwelling older persons.
Participants: 660 older participants (age ≥ 65 years).
Measurements: usual gait speed, fastest gait speed, gait speed during 'walking-while-talking', depression, comorbidities, education, smoking and demographics were assessed at baseline. Cognition was evaluated at baseline and follow-up. A decline in MMSE score by ≥ 3 points was considered as significant cognitive decline (SCD).
Results: adjusting for confounders, only fast speed was associated with cognitive performance at 3-year follow-up. One hundred thirty-five participants had SCD over 3 years. Participants in the lowest quartile of usual speed or walking-while-talking speed were more likely to develop SCD. Conversely, participants in the third and fourth quartiles of fast speed were more likely to develop SCD. J-test showed that the model including fast speed quartiles as a regressor was significantly more predictive of SCD than the models with usual speed or walking-while-talking speed quartiles.
Conclusion: measuring fast gait speed in older persons may assist in identifying those at high risk of cognitive decline.
Cross-sectional studies have shown associations between cognition and physical performance in older persons, suggesting that they are interrelated. Very few studies have investigated whether physical performance predicts decline in cognition and suggest that slower usual gait speed predicts accelerated cognitive decline in the oldest old. However, many studies included only healthy elderly or did not consider potential confounders other than cardiovascular risk factors. It is also reported that poorer cognitive function predicts slower walking speed. However, available evidence suggests that subtle changes in motor functions precede cognitive impairment. Using data from a population-based study, we investigated whether gait speed is an independent predictor of cognitive decline over 3 years.
Walking at usual self-selected speed is an automated motor behaviour that requires limited cognitive resources. Thus, gait speed under challenging conditions (either cognitively or physically challenging) may predict cognitive decline better than performance in usual walking tasks. Indeed, in older individuals, rapid walking speed is a better correlate of cognitive function compared to usual walking speed. Further, a cross-sectional association between executive function and gait variability is evident only after a cognitive challenge is added during walking. Whether gait speed under different challenges independently predicts evolving cognitive decline is unknown. This information is clinically and theoretically important for developing simple criteria for characterising and tracking cognitive function in older adults and for developing further insight into mechanisms that lead to parallel decline of physical and cognitive function in older individuals.
We hypothesised that compared to usual gait speed, gait speeds under a physical or a cognitive challenge will be stronger predictors of cognitive decline over time and those in the lower quartiles of the gait speed under a physical challenge or a cognitive challenge will be more likely to demonstrate significant cognitive decline.
Abstract and Introduction
Abstract
Objective: to examine whether usual gait speed, fast gait speed or speed while walking with a cognitive or neuromuscular challenge predicts evolving cognitive decline over 3 years.
Design: prospective study.
Setting: population-based sample of community-dwelling older persons.
Participants: 660 older participants (age ≥ 65 years).
Measurements: usual gait speed, fastest gait speed, gait speed during 'walking-while-talking', depression, comorbidities, education, smoking and demographics were assessed at baseline. Cognition was evaluated at baseline and follow-up. A decline in MMSE score by ≥ 3 points was considered as significant cognitive decline (SCD).
Results: adjusting for confounders, only fast speed was associated with cognitive performance at 3-year follow-up. One hundred thirty-five participants had SCD over 3 years. Participants in the lowest quartile of usual speed or walking-while-talking speed were more likely to develop SCD. Conversely, participants in the third and fourth quartiles of fast speed were more likely to develop SCD. J-test showed that the model including fast speed quartiles as a regressor was significantly more predictive of SCD than the models with usual speed or walking-while-talking speed quartiles.
Conclusion: measuring fast gait speed in older persons may assist in identifying those at high risk of cognitive decline.
Introduction
Cross-sectional studies have shown associations between cognition and physical performance in older persons, suggesting that they are interrelated. Very few studies have investigated whether physical performance predicts decline in cognition and suggest that slower usual gait speed predicts accelerated cognitive decline in the oldest old. However, many studies included only healthy elderly or did not consider potential confounders other than cardiovascular risk factors. It is also reported that poorer cognitive function predicts slower walking speed. However, available evidence suggests that subtle changes in motor functions precede cognitive impairment. Using data from a population-based study, we investigated whether gait speed is an independent predictor of cognitive decline over 3 years.
Walking at usual self-selected speed is an automated motor behaviour that requires limited cognitive resources. Thus, gait speed under challenging conditions (either cognitively or physically challenging) may predict cognitive decline better than performance in usual walking tasks. Indeed, in older individuals, rapid walking speed is a better correlate of cognitive function compared to usual walking speed. Further, a cross-sectional association between executive function and gait variability is evident only after a cognitive challenge is added during walking. Whether gait speed under different challenges independently predicts evolving cognitive decline is unknown. This information is clinically and theoretically important for developing simple criteria for characterising and tracking cognitive function in older adults and for developing further insight into mechanisms that lead to parallel decline of physical and cognitive function in older individuals.
We hypothesised that compared to usual gait speed, gait speeds under a physical or a cognitive challenge will be stronger predictors of cognitive decline over time and those in the lower quartiles of the gait speed under a physical challenge or a cognitive challenge will be more likely to demonstrate significant cognitive decline.
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