title: Global and regional associations of smaller cerebral gray and white matter volumes with gait in older people.
abstract: BACKGROUND
  Gait impairments increase with advancing age and can lead to falls and loss of independence. Brain atrophy also occurs in older age and may contribute to gait decline. We aimed to investigate global and regional relationships of cerebral gray and white matter volumes with gait speed, and its determinants step length and cadence, in older people.
  
  
  METHODS
  In a population-based study, participants aged >60 years without Parkinson's disease or brain infarcts underwent magnetic resonance imaging and gait measurements using a computerized walkway. Linear regression was used to study associations of total gray and white matter volumes with gait, adjusting for each other, age, sex, height and white matter hyperintensity volume. Other covariates considered in analyses included weight and vascular disease history. Voxel-based morphometry was used to study regional relationships of gray and white matter with gait.
  
  
  RESULTS
  There were 305 participants, mean age 71.4 (6.9) years, 54% male, mean gait speed 1.16 (0.22) m/s. Smaller total gray matter volume was independently associated with poorer gait speed (p = 0.001) and step length (p<0.001), but not cadence. Smaller volumes of cortical and subcortical gray matter in bilateral regions important for motor control, vision, perception and memory were independently associated with slower gait speed and shorter steps. No global or regional associations were observed between white matter volume and gait independent of gray matter volume, white matter hyperintensity volume and other covariates.
  
  
  CONCLUSIONS
  Smaller gray matter volume in bilaterally distributed brain networks serving motor control was associated with slower gait speed and step length, but not cadence.
authors.affiliation: Stroke and Ageing Research Group, Department of Medicine, Southern Clinical School, Monash University, Clayton, Victoria, Australia ; Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: Michele L
authors.initials: ML
authors.lastname: Callisaya
authors.affiliation: Stroke and Ageing Research Group, Department of Medicine, Southern Clinical School, Monash University, Clayton, Victoria, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Beare
authors.affiliation: Stroke and Ageing Research Group, Department of Medicine, Southern Clinical School, Monash University, Clayton, Victoria, Australia.
authors.forename: Thanh G
authors.initials: TG
authors.lastname: Phan
authors.affiliation: Stroke and Ageing Research Group, Department of Medicine, Southern Clinical School, Monash University, Clayton, Victoria, Australia.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.affiliation: Stroke and Ageing Research Group, Department of Medicine, Southern Clinical School, Monash University, Clayton, Victoria, Australia ; Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: Velandai K
authors.initials: VK
authors.lastname: Srikanth
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000033:anatomy & histology* / Q000166:cytology / Q000502:physiology; D005260:Female; D005684:Gait; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009929:Organ Size