title: Effect of dual-tasking on dynamic postural control in individuals with and without nonspecific low back pain.
abstract: OBJECTIVE
  The purpose of this study was to compare the effect of dual tasking on postural and cognitive performance between participants with and without nonspecific chronic low back pain.
  
  
  METHODS
  In this 3-factor mixed-design study, dynamic postural stability was assessed in 15 patients with chronic nonspecific low back pain and 15 age-, sex-, and size-matched asymptomatic participants. Bilateral stance on a Biodex Balance System was investigated at 3 levels of postural task difficulty (different platform stabilities levels with eyes open and closed) and 2 levels of cognitive task difficulty (with or without auditory Stroop test). We measured anterior-posterior, medial-lateral, and overall indices for postural performance. Average reaction time and error ratio of a modified auditory Stroop test were calculated as measures of the cognitive task performance.
  
  
  RESULTS
  Mixed-design 3-way analyses of variance revealed significant interactions. Post hoc 2-way analyses of variance showed significant group by cognitive task difficulty for anterior-posterior (P < .001), medial-lateral (P = .003), and overall stability indices (P < .001) on a stiffness level of 5 with eyes closed. At this level, there were significant differences between single- and dual-task conditions for anterior-posterior (P < .001), medial-lateral (P = .02), and overall stability indices (P < .001) only in the chronic low back pain group. Also, at the most difficult postural conditions, participants with chronic low back pain increased their error ratio (P = .002), whereas matched asymptomatic individuals increased their reaction time (P < .01) of the auditory Stroop test.
  
  
  CONCLUSIONS
  Postural task performance is attenuated by cognitive loading at a moderate level of postural task difficulty. Therefore, to observe the effect of attentional demands of postural control, task difficulty should be considered.
authors.affiliation: PhD Student in Physical Therapy, Physiotherapy Department, Iran University of Medical Science, Tehran, Iran.
authors.forename: Shiva
authors.initials: S
authors.lastname: Sherafat
authors.affiliation: Professor, Physiotherapy Department, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Electronic address: mahyarsalavati@gmail.com.
authors.forename: Mahyar
authors.initials: M
authors.lastname: Salavati
authors.affiliation: Professor in Physical Therapy, Physiotherapy Department, Rehabilitation Faculty, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Ismail Ebrahimi
authors.initials: IE
authors.lastname: Takamjani
authors.affiliation: Associate Professor, Physiotherapy Department, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: Behnam
authors.initials: B
authors.lastname: Akhbari
authors.affiliation: PhD Student in Physical Therapy, Physiotherapy Department, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: Shahrzad Mohammadi
authors.initials: SM
authors.lastname: Rad
authors.affiliation: Assistant Professor, Musculoskeletal Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Masood
authors.initials: M
authors.lastname: Mazaheri
authors.affiliation: Associate Professor, Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Negahben
authors.affiliation: MSc in Energy Engineering, Amirkabir University of Technology, Tehran, Iran.
authors.forename: Pezhman
authors.initials: P
authors.lastname: Lali
mesh_terms: D003071:Cognition; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000503:physiopathology*; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D013647:Task Performance and Analysis; D055815:Young Adult
keywords: Attention; Low Back Pain; Postural Balance; Stroop Test