title: Prevalence of Walking-Related Motor Fatigue in Persons With Multiple Sclerosis: Decline in Walking Distance Induced by the 6-Minute Walk Test.
abstract: OBJECTIVE
  To investigate the individual occurrence of walking-related motor fatigue in persons with multiple sclerosis (PwMS), according to disability level and disease phenotype.Study design This was a cross-sectional, multinational study.Participants They were 208 PwMS from 11 centers with Expanded Disability Status Scale (EDSS) scores up to 6.5.
  
  
  METHODS
  The percentage change in distance walked (distance walked index, DWI) was calculated between minute 6 and 1 (DWI(6-1)) of the 6-Minute Walk Test (6MWT). Its magnitude was used to classify participants into 4 subgroups: (1) DWI(6-1)[≥5%], (2) DWI(6-1)[5%; -5%], (3) DWI(6-1)[-5%; > -15%], and (4) DWI(6-1)[≤-15%]. The latter group was labeled as having walking-related motor fatigue. PwMS were stratified into 5 subgroups based on the EDSS (0-2.5, 3-4, 4.5-5.5, 6, 6.5) and 3 subgroups based on MS phenotype (relapsing remitting [RR], primary progressive [PP], and secondary progressive [SP]).
  
  
  RESULTS
  The DWI6-1was ≥5% in 16 PwMS (7.7%), between 5% and -5% in 70 PwMS (33.6%), between -5% and -15% in 58 PwMS (24%), and ≤-15% in 64 PwMS (30.8%). The prevalence of walking-related motor fatigue (DWI(6-1)[≤-15%]) was significantly higher among the progressive phenotype (PP = 50% and SP = 39%; RR = 15.6%) and PwMS with higher disability level (EDSS 4.5-5.5 = 48.3%, 6 = 46.3% and 6.5 = 51.5%, compared with EDSS 0-2.5 = 7.8% and 3-4 = 16.7%;P< .05). Stepwise multiple regression analysis indicated that EDSS, but not MS phenotype, explained a significant part of the variance in DWI(6-1)(R(2)= 0.086;P< .001).
  
  
  CONCLUSIONS
  More than one-third of PwMS showed walking-related motor fatigue during the 6MWT, with its prevalence greatest in more disabled persons (up to 51%) and in those with progressive MS phenotype (up to 50%). Identification of walking-related motor fatigue may lead to better-tailored interventions.
authors.affiliation: BIOMED, Hasselt University, Hasselt, Belgium Department of Neurosciences GF Ingrassia, University of Catania, Catania carmelaleone84@yahoo.it.
authors.forename: Carmela
authors.initials: C
authors.lastname: Leone
authors.affiliation: BIOMED, Hasselt University, Hasselt, Belgium.
authors.forename: Deborah
authors.initials: D
authors.lastname: Severijns
authors.affiliation: BIOMED, Hasselt University, Hasselt, Belgium.
authors.forename: Vendula
authors.initials: V
authors.lastname: Doležalová
authors.affiliation: BIOMED, Hasselt University, Hasselt, Belgium.
authors.forename: Ilse
authors.initials: I
authors.lastname: Baert
authors.affiliation: Department Public Health, Section of Sport Science, Aarhus University, Aarhus, Denmark.
authors.forename: Ulrik
authors.initials: U
authors.lastname: Dalgas
authors.affiliation: Masku Neurological Rehabilitation Center, Masku, Finland.
authors.forename: Anders
authors.initials: A
authors.lastname: Romberg
authors.affiliation: Mellen Center for MS Treatment and Research, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Francois
authors.initials: F
authors.lastname: Bethoux
authors.affiliation: National MS Center, Melsbroek, Belgium.
authors.forename: Benoit
authors.initials: B
authors.lastname: Gebara
authors.affiliation: Hospital de Dia de Barcelona CEMCat, Barcelona, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Santoyo Medina
authors.affiliation: West-Tallinn Central Hospital, Tallinn, Estonia.
authors.forename: Heigo
authors.initials: H
authors.lastname: Maamâgi
authors.affiliation: Department of Rehabilitation, Third Faculty of Medicine, Charles University in Prague, Czech Republic.
authors.forename: Kamila
authors.initials: K
authors.lastname: Rasova
authors.affiliation: Centre Neurologique et de Réadaptation Fonctionelle Fraiture-en-Condroz, Begium.
authors.forename: Benoît
authors.initials: B
authors.lastname: Maertens de Noordhout
authors.affiliation: Rehabilitation and MS Center, Overpelt, Belgium.
authors.forename: Kathy
authors.initials: K
authors.lastname: Knuts
authors.affiliation: MS Hospitals Ry&Haslev, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Skjerbaek
authors.affiliation: MS Hospitals Ry&Haslev, Denmark.
authors.forename: Ellen
authors.initials: E
authors.lastname: Jensen
authors.affiliation: Saint Louis University, St. Louis, MO, USA.
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Wagner
authors.affiliation: BIOMED, Hasselt University, Hasselt, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Feys
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005221:Fatigue / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology*; D015995:Prevalence; D016138:Walking / Q000502:physiology*
keywords: 6-Minute Walk Test; deceleration index; distance walked index; motor fatigue; walking