title: Intraindividual variability in executive functions but not speed of processing or conflict resolution predicts performance differences in gait speed in older adults.
abstract: BACKGROUND
  The relationship between executive functions (EF) and gait speed is well established. However, with the exception of dual tasking, the key components of EF that predict differences in gait performance have not been determined. Therefore, the current study was designed to determine whether processing speed, conflict resolution, and intraindividual variability in EF predicted variance in gait performance in single- and dual-task conditions.
  
  
  METHODS
  Participants were 234 nondemented older adults (mean age 76.48 years; 55% women) enrolled in a community-based cohort study. Gait speed was assessed using an instrumented walkway during single- and dual-task conditions. The flanker task was used to assess EF.
  
  
  RESULTS
  Results from the linear mixed effects model showed that (a) dual-task interference caused a significant dual-task cost in gait speed (estimate = 35.99; 95% CI = 33.19-38.80) and (b) of the cognitive predictors, only intraindividual variability was associated with gait speed (estimate = -.606; 95% CI = -1.11 to -.10). In unadjusted analyses, the three EF measures were related to gait speed in single- and dual-task conditions. However, in fully adjusted linear regression analysis, only intraindividual variability predicted performance differences in gait speed during dual tasking (B = -.901; 95% CI = -1.557 to -.245).
  
  
  CONCLUSIONS
  Among the three EF measures assessed, intraindividual variability but not speed of processing or conflict resolution predicted performance differences in gait speed.
authors.affiliation: Ferkauf Graduate School of Psychology, Albert Einstein School of Medicine, Yeshiva University, New York. Department of Neurology, Albert Einstein School of Medicine, Yeshiva University, New York. roee.holtzer@einstein.yu.edu.
authors.forename: Roee
authors.initials: R
authors.lastname: Holtzer
authors.affiliation: Department of Neurology, Albert Einstein School of Medicine, Yeshiva University, New York.
authors.forename: Jeannette
authors.initials: J
authors.lastname: Mahoney
authors.affiliation: Department of Neurology, Albert Einstein School of Medicine, Yeshiva University, New York.
authors.forename: Joe
authors.initials: J
authors.lastname: Verghese
mesh_terms: D000368:Aged; D001288:Attention / Q000502:physiology; D003071:Cognition / Q000502:physiology; D015331:Cohort Studies; D056344:Executive Function / Q000502:physiology*; D005260:Female; D005684:Gait / Q000502:physiology*; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D011340:Problem Solving / Q000502:physiology; D013647:Task Performance and Analysis; D016138:Walking / Q000502:physiology
keywords: Aging; Cognitive control; Dual tasks.; Mobility