title: Motor fatigue measurement by distance-induced slow down of walking speed in multiple sclerosis.
abstract: OBJECTIVE
  Motor fatigue and ambulation impairment are prominent clinical features of people with multiple sclerosis (pMS). We hypothesized that a multimodal and comparative assessment of walking speed on short and long distance would allow a better delineation and quantification of gait fatigability in pMS. Our objectives were to compare 4 walking paradigms: the timed 25-foot walk (T25FW), a corrected version of the T25FW with dynamic start (T25FW(+)), the timed 100-meter walk (T100MW) and the timed 500-meter walk (T500MW).
  
  
  METHODS
  Thirty controls and 81 pMS performed the 4 walking tests in a single study visit.
  
  
  RESULTS
  The 4 walking tests were performed with a slower WS in pMS compared to controls even in subgroups with minimal disability. The finishing speed of the last 100-meter of the T500MW was the slowest measurable WS whereas the T25FW(+) provided the fastest measurable WS. The ratio between such slowest and fastest WS (Deceleration Index, DI) was significantly lower only in pMS with EDSS 4.0-6.0, a pyramidal or cerebellar functional system score reaching 3 or a maximum reported walking distance ≤ 4000 m.
  
  
  CONCLUSIONS
  The motor fatigue which triggers gait deceleration over a sustained effort in pMS can be measured by the WS ratio between performances on a very short distance and the finishing pace on a longer more demanding task. The absolute walking speed is abnormal early in MS whatever the distance of effort when patients are unaware of ambulation impairment. In contrast, the DI-measured ambulation fatigability appears to take place later in the disease course.
authors.affiliation: MYelin Disorders REseArch teaM, Liège, Belgium. remy.phanba@chu.ulg.ac.be
authors.forename: Rémy
authors.initials: R
authors.lastname: Phan-Ba
authors.forename: Philippe
authors.initials: P
authors.lastname: Calay
authors.forename: Patrick
authors.initials: P
authors.lastname: Grodent
authors.forename: Gael
authors.initials: G
authors.lastname: Delrue
authors.forename: Emilie
authors.initials: E
authors.lastname: Lommers
authors.forename: Valérie
authors.initials: V
authors.lastname: Delvaux
authors.forename: Gustave
authors.initials: G
authors.lastname: Moonen
authors.forename: Shibeshih
authors.initials: S
authors.lastname: Belachew
mesh_terms: D000328:Adult; D004185:Disability Evaluation; D005221:Fatigue / Q000503:physiopathology; D005260:Female; D020233:Gait Disorders, Neurologic / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology*; D016138:Walking / Q000502:physiology*; D055815:Young Adult