Lap time variation and executive function in older adults: The Baltimore Longitudinal Study of Aging

Qu Tian, Eleanor M. Simonsick, Susan M. Resnick, Michelle D. Shardell, Luigi Ferrucci, Stephanie A. Studenski

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Background: poor cognitive and motor performance predicts neurological dysfunction. Variable performance may be a subclinical indicator of emerging neurological problems. Objective: examine the cross-sectional association between a clinically accessible measure of variable walking and executive function. Methods: older adults aged 60 or older from the Baltimore Longitudinal Study of Aging (n = 811) with data on the 400-m walk test and cognition. Based on ten 40-m laps, we calculated mean lap time (MLT) and variation in time across ten 40-m laps (lap time variation, LTV). Executive function tests assessed attention and short-term memory (digit span forward and backward), psychomotor speed [Trail Making Test (TMT) part A] and multicomponent tasks requiring cognitive flexibility [TMT part B, part B-A (Delta TMT) and digit symbol substitution test (DSST)]. Multivariate linear regression analysis examined the cross-sectional association between LTV and executive function, adjusted for MLT, age, sex and education, as well as the LTV × MLT interaction. Results: the LTV was univariately associated with all executive function tests except digit span (P < 0.001); after adjustment, the association with TMT part A remained (standardised β = 0.142, P = 0.002). There was an interaction between MLT and LTV; among fast walkers, greater LTV was associated with a greater Delta TMT (β for LTV × MLT = -1.121, P = 0.016) after adjustment. Conclusion: at any walking speed, greater LTV is associated with psychomotor slowing. Among persons with faster walking speed, variation is associated with worse performance on a complex measure of cognitive flexibility. A simple measure of variability in walking time is independently associated with psychomotor slowing.

Original languageEnglish (US)
Article numberafv076
Pages (from-to)796-800
Number of pages5
JournalAge and ageing
Issue number5
StatePublished - Sep 1 2015


  • Cognitive flexibility
  • Lap time variation
  • Older people
  • Psychomotor speed

ASJC Scopus subject areas

  • Aging
  • Geriatrics and Gerontology


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