Gait speed under varied challenges and cognitive decline in older persons: a prospective study.

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 > or = 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 > or = 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.