title: Respective and combined effects of impairments in sensorimotor systems and cognition on gait performance: a population-based cross-sectional study.
abstract: BACKGROUND
  Respective and combined effects of impairments in sensorimotor systems and cognition on gait performance have not been fully studied. This study aims to describe the respective effects of impairments in muscle strength, distance vision, lower-limb proprioception and cognition on the Timed Up & Go (TUG) scores (i.e., performed TUG [pTUG], imagined TUG [iTUG] and the time difference between these two tests [delta TUG]) in older community-dwellers; and to examine their combined effects on TUG scores.
  
  
  METHODS
  Based on a cross-sectional design, 1792 community-dwellers (70.2 ± 4.8 years; 53.6% female) were recruited. Gait performance was assessed using pTUG, iTUG and delta TUG. Participants were divided into healthy individuals and 15 subgroups of individuals according to the presence of impairment in one or more subsystems involved in gait control (i.e., muscle strength and/or distance vision and/or lower-limb proprioception and/or cognition [episodic memory and executive performance]). Impairment in muscle strength, distance vision and lower-limb proprioception was defined as being in the lowest tertile of performance. Impairment in cognition was defined as abnormal episodic memory and executive tests.
  
  
  RESULTS
  A total of 191 (10.7%) exhibited impairment in muscle strength, 188 (10.5%) in distance vision, 302 (16.9%) in lower-limb proprioception, and 42 (2.3%) in cognition. Linear regressions showed that cognitive impairment as well as dual combinations of impairments were associated with increased pTUG (P<0.02). Impairment in lower-limb proprioception was associated with decreased iTUG (P=0.015). All combinations of impairments, except those including muscle strength and the combinations of the 4 subsystems, were associated with increased delta TUG (P<0.04).
  
  
  CONCLUSIONS
  Cognitive integrity is central for efficient gait control and stability, whereas lower-limb proprioception seems to be central for gait imagery.
authors.affiliation: Department of Neuroscience, Division of Geriatric Medicine, Angers University Hospital, Angers, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Beauchet
authors.affiliation: Department of Neuroscience, Division of Geriatric Medicine, Angers University Hospital, Angers, France.
authors.forename: Cyrille P
authors.initials: CP
authors.lastname: Launay
authors.affiliation: Department of Neuroscience, Division of Geriatric Medicine, Angers University Hospital, Angers, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Fantino
authors.affiliation: Department of Neurology, Geneva University Hospital and University of Geneva, Switzerland; Department of Neurology, Division of Cognitive & Motor Aging, Albert Einstein College of Medicine, Yeshiva University, Bronx, New York, United States of America.
authors.forename: Gilles
authors.initials: G
authors.lastname: Allali
authors.affiliation: Department of Neuroscience, Division of Geriatric Medicine, Angers University Hospital, Angers, France; Robarts Research Institute, Department of Medical Biophysics, Schulich School of Medicine and Dentistry, the University of Western Ontario, London, Ontario, Canada.
authors.forename: Cédric
authors.initials: C
authors.lastname: Annweiler
mesh_terms: D000368:Aged; D003071:Cognition; D003430:Cross-Sectional Studies; D005260:Female; D005602:France; D005684:Gait; D006801:Humans; D008297:Male