title: White matter hyperintensities, exercise, and improvement in gait speed: does type of gait rehabilitation matter?
abstract: OBJECTIVE
  To examine whether white matter hyperintensities (WMHs) on brain magnetic resonance imaging (MRI) in tracts in older adults with mobility impairment are linked to outcomes of gait rehabilitation interventions.
  
  
  METHODS
  Twelve-week randomized controlled single-blind trial.
  
  
  METHODS
  University-based mobility research laboratory.
  
  
  METHODS
  Ambulatory adults aged 65 and older with mobility impairment.
  
  
  METHODS
  A conventional gait intervention focusing on walking, endurance, balance, and strength (WEBS, n = 21) and a task-oriented intervention focused on timing and coordination of gait (TC, n = 23).
  
  
  METHODS
  Self-paced gait speed was measured over an instrumented walkway before and after the intervention, and WMH and brain volumes were quantified on preintervention brain MRI using an automated segmentation process. A white matter tract atlas was overlaid on the segmented images to measure tract WMH volumes, and WMH volumes were normalized to total brain volume. Aggregate WMH volumes in all white matter tracts and individual WMH volumes in specific longitudinal tracts (superior longitudinal fasciculus, inferior longitudinal fasciculus, and fronto-occipital fasciculus) and the cingulum were measured.
  
  
  RESULTS
  Gait speed gains in the TC group were of the same magnitude, independent of WMH volume measures in all except the cingulum, but in the WEBS group, gain in gait speed was smaller with greater overall tract WMH volumes (P < .001) and with greater WMH volume in the three longitudinal tracts (P < .001 to .02).
  
  
  CONCLUSIONS
  Gains in gait speed with two types of gait rehabilitation are associated with individual differences in WMHs. Task-oriented therapy that targets timing and coordination of gait may particularly benefit older adults with WMHs in brain tracts that influence gait and cognition.
authors.affiliation: Division of Geriatric Medicine and Gerontology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA. nkn3@pitt.edu
authors.forename: Neelesh K
authors.initials: NK
authors.lastname: Nadkarni
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Studenski
authors.forename: Subashan
authors.initials: S
authors.lastname: Perera
authors.forename: Caterina
authors.initials: C
authors.lastname: Rosano
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Aizenstein
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Brach
authors.forename: Jessie M
authors.initials: JM
authors.lastname: Van Swearingen
mesh_terms: D000368:Aged; D002540:Cerebral Cortex / Q000473:pathology*; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D005684:Gait / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D051346:Mobility Limitation; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D016037:Single-Blind Method; D016138:Walking / Q000502:physiology*