title: Symmetry matched auditory cues improve gait steadiness in most people with Parkinson's disease but not in healthy older people.
abstract: BACKGROUND
  Unsteady gait and falls are major problems for people with Parkinson's disease (PD). Symmetric auditory cues at altered cadences have been used to improve walking speed or step length. However, few people are exactly symmetric in terms of morphology or movement patterns and effects of symmetric cueing on gait steadiness are inconclusive.
  
  
  OBJECTIVE
  To investigate if matching auditory cue a/symmetry to an individual's intrinsic symmetry or asymmetry affects gait steadiness, gait symmetry, and comfort to cues, in people with PD, healthy age-matched controls (HAM) and young.
  
  
  METHODS
  Thirty participants; 10 with PD, 11 HAM (66 years), and 9 young (30 years), completed five baseline walks (no cues) and twenty-five cued walks at habitual cadence but different a/symmetries. Outcomes included; gait steadiness (step time variability and smoothness by harmonic ratios), walking speed, symmetry, comfort, and cue lag times.
  
  
  RESULTS
  Without cues, PD participants had slower and less steady gait than HAM or young. Gait symmetry was distinct from gait steadiness, and unaffected by cue symmetry or a diagnosis of PD, but associated with aging. All participants maintained preferred gait symmetry and lag times independent of cue symmetry. When cues were matched to the individual's habitual gait symmetry and cadence: Gait steadiness improved in the PD group, but deteriorated in the HAM controls, and was unchanged in the young. Gait outcomes worsened for the two PD participants who reported discomfort to cued walking and had high New Freezing of Gait scores.
  
  
  CONCLUSIONS
  It cannot be assumed all individuals benefit equally from auditory cues. Symmetry matched auditory cues compensated for unsteady gait in most people with PD, but interfered with gait steadiness in older people without basal ganglia deficits.
authors.affiliation: Falls and Balance Research Group, Neuroscience Research Australia, University of New South Wales, Sydney, Australia.
authors.forename: Matthew A D
authors.initials: MA
authors.lastname: Brodie
authors.affiliation: MARCS Institute, University of Western Sydney, Sydney, Australia.
authors.forename: Roger T
authors.initials: RT
authors.lastname: Dean
authors.affiliation: Neurology, Canisius Wilhelmina Hospital, Nijmegen, Netherlands.
authors.forename: Tim R
authors.initials: TR
authors.lastname: Beijer
authors.affiliation: Clinical and Rehabilitation Sciences Research Group, Faculty of Health Sciences, University of Sydney, Sydney, Australia.
authors.forename: Colleen G
authors.initials: CG
authors.lastname: Canning
authors.affiliation: School of Health Sciences, University of Tasmania, Launceston, Australia.
authors.forename: Stuart T
authors.initials: ST
authors.lastname: Smith
authors.affiliation: Falls and Balance Research Group, Neuroscience Research Australia, University of New South Wales, Sydney, Australia.
authors.forename: Jasmine C
authors.initials: JC
authors.lastname: Menant
authors.affiliation: Falls and Balance Research Group, Neuroscience Research Australia, University of New South Wales, Sydney, Australia.
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Lord
mesh_terms: D000054:Acceleration; D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D003463:Cues; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications*; D018709:Statistics, Nonparametric; D016896:Treatment Outcome; D016138:Walking; D055815:Young Adult
keywords: Auditory cues; Parkinson's disease; asymmetry; gait steadiness; symmetry