title: Association between physical fitness and cognitive function in multiple sclerosis: does disability status matter?
abstract: BACKGROUND
  Cognitive impairment is a highly prevalent, poorly managed, and disabling consequence of multiple sclerosis (MS). Exercise training that improves physical fitness represents a promising approach for managing cognitive impairment in persons with MS. There is limited evidence that physical fitness is associated with multiple domains of cognitive dysfunction across levels of MS disability.
  
  
  OBJECTIVE
  This cross-sectional study examined the associations among aerobic capacity, lower limb muscle strength, and cognitive functions in persons with mild, moderate, and severe MS disability.
  
  
  METHODS
  The sample included 62 persons with mild (n = 20), moderate (n = 21), and severe (n = 21) MS disability. The participants underwent neuropsychological assessments of cognitive processing speed (CPS; Symbol Digit Modalities Test [SDMT]), verbal memory (California Verbal Learning Test-2 [CVLT-2]), and visual memory (Brief Visuospatial Memory Test-Revised [BVMT-R]). All participants further underwent testing for measuring aerobic capacity (ie, peak oxygen consumption) and muscular strength (ie, peak torque of knee flexors and extensors).
  
  
  RESULTS
  Aerobic capacity and muscular strength outcomes were associated with SDMT (r = .35-.41), but not CVLT-2 or BVMT-R (r < .19) scores in the overall sample. Aerobic capacity (r = .42) and knee flexor peak torque (r = .39) were associated with SDMT scores in persons with mild disability, but not in those with moderate (r < .06) and severe (r < .14) disability.
  
  
  CONCLUSIONS
  These results support examining aerobic and resistance exercise training programs for improving CPS, particularly among persons with mild MS disability.
authors.affiliation: University of Illinois at Urbana-Champaign, Urbana, IL, USA.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Sandroff
authors.affiliation: University of Illinois at Urbana-Champaign, Urbana, IL, USA.
authors.forename: Lara A
authors.initials: LA
authors.lastname: Pilutti
authors.affiliation: University at Buffalo, State University of New York, Buffalo, NY, USA.
authors.forename: Ralph H B
authors.initials: RH
authors.lastname: Benedict
authors.affiliation: University of Illinois at Urbana-Champaign, Urbana, IL, USA robmotl@illinois.edu.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Motl
mesh_terms: D003071:Cognition; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology* / Q000523:psychology*; D053580:Muscle Strength; D009483:Neuropsychological Tests; D010101:Oxygen Consumption; D010809:Physical Fitness; D012720:Severity of Illness Index
keywords: cognition; cognitive processing speed; disability; exercise; multiple sclerosis; physical fitness