title: The effects of a secondary task on forward and backward walking in Parkinson's disease.
abstract: BACKGROUND
  People with Parkinson's disease (PD) often fall while multitasking or walking backward, unavoidable activities in daily living. Dual tasks involving cognitive demand during gait and unfamiliar motor skills, such as backward walking, could identify those with fall risk, but dual tasking while walking backward has not been examined in those with PD, those who experience freezing of gait (FOG), or healthy older controls.
  
  
  METHODS
  A total of 78 people with PD (mean age = 65.1 +/-9.5 years; female, 28%) and 74 age-matched and sex-matched controls (mean age = 65.0 +/-10.0 years; female, 23%) participated. A computerized walkway measured gait velocity, stride length, swing percent, stance percent, cadence, heel to heel base of support, functional ambulation profile, and gait asymmetry during forward and backward walking with and without a secondary cognitive task.
  
  
  RESULTS
  Direction and task effects on walking performance were similar between healthy controls and those with PD. However, those with PD were more affected than controls, and freezers were more affected than nonfreezers, by backward walking and dual tasking. Walking backward seemed to affect gait more than dual tasking in those with PD,although the subset of freezers appeared particularly affected by both challenges.
  
  
  CONCLUSIONS
  People with PD are impaired while performing complex motor and mental tasks simultaneously,which may put them at risk for falling. Those with FOG are more adversely affected by both motor and mental challenges than those without. Evaluation of backward walking while performing a secondary task might be an effective clinical tool to identify locomotor difficulties.
authors.affiliation: Washington University School of Medicine, St Louis, Missouri 63108, USA.
authors.forename: Madeleine E
authors.initials: ME
authors.lastname: Hackney
authors.forename: Gammon M
authors.initials: GM
authors.lastname: Earhart
mesh_terms: D000368:Aged; D001288:Attention; D001696:Biomechanical Phenomena; D003071:Cognition; D005260:Female; D005684:Gait; D006801:Humans; D008297:Male; D055641:Mathematical Concepts; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000503:physiopathology* / Q000523:psychology*; D016138:Walking
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