title: Dual task cost of cognition is related to fall risk in patients with multiple sclerosis: a prospective study.
abstract: OBJECTIVE
  To examine whether change in cognitive performance during dual task condition compared with a task in isolation, known as dual task cost, is related to fall risk of patients with multiple sclerosis.
  
  
  METHODS
  Prospective cohort. During baseline assessment, data about balance, walking and cognitive performance of patients with multiple sclerosis were collected under a single and dual task condition. The dual task cost was calculated as a percentage of change in parameters from single to dual task conditions. Falls were recorded prospectively for six months and participants were classified as none/one time fallers and recurrent fallers (⩾2 falls). The association between dual task costs and fall status was evaluated by logistic regression.
  
  
  METHODS
  Balance research lab of university hospital.
  
  
  METHODS
  A total of 60 patients with relapsing-remitting multiple sclerosis.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  The dual task cost of the center of pressure sway area, walking velocity and correct response rate were outcome measures for balance, walking and cognitive performance, respectively.
  
  
  RESULTS
  A total of 79 falls were reported by 38 of the participants who experienced one or more falls; 26 (43.3%) of them had recurrent falls. Dual tasking resulted in increased sway area and decreased walking velocity and correct response rate during walking (all p values <0.05). Logistic regressions showed that the dual task cost of the correct response rate during walking and walking velocity were associated with increased risk of recurrent falls ( P = 0.02, odds ratio = 1.34; confidence interval (CI) 1.04-3.74; P =  0.05, odds ratio = 1.23, CI = 1.02-4.45, respectively).
  
  
  CONCLUSIONS
  The dual task cost of cognition was related to fall, which should be considered as a target for falls evaluation and prevention strategies.
authors.affiliation: Department of Rehabilitation Science, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: Yasaman
authors.initials: Y
authors.lastname: Etemadi
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control*; D000328:Adult; D003071:Cognition / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications / Q000503:physiopathology*; D016017:Odds Ratio; D004856:Postural Balance / Q000502:physiology*; D011446:Prospective Studies; D011597:Psychomotor Performance / Q000502:physiology; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D013647:Task Performance and Analysis
keywords: Multiple sclerosis; balance; cognitive impairment; cognitive-motor interference; falls