title: Does Nordic Walking restore the temporal organization of gait variability in Parkinson's disease?
abstract: BACKGROUND
  Gait disorders of Parkinson's disease (PD) are characterized by the breakdown of the temporal organization of stride duration variability that was tightly associated to dynamic instability in PD. Activating the upper body during walking, Nordic Walking (NW) may be used as an external cueing to improve spatiotemporal parameters of gait, such as stride length or gait variability, in PD. The aim of this study was to evaluate the beneficial effects of NW on temporal organization of gait variability and spatiotemporal gait variables in PD.
  
  
  METHODS
  Fourteen mild to moderate PD participants and ten age-matched healthy subjects performed 2 × 12 min overground walking sessions (with and without pole in a randomized order) at a comfortable speed. Gait speed, cadence, step length and temporal organization (i.e. long-range autocorrelations; LRA) of stride duration variability were studied on 512 consecutive gait cycles using a unidimensional accelerometer placed on the malleola of the most affected side in PD patients and of the dominant side in healthy controls. The presence of LRA was determined using the Rescaled Range Analysis (Hurst exponent) and the Power Spectral Density (α exponent). To assess NW and disease influences on gait, paired t-tests, Z-score and a two-way (pathological condition x walking condition) ANOVA repeated measure were used.
  
  
  RESULTS
  Leading to significant improvement of LRA, NW enhances step length and reduces gait cadence without any change in gait speed in PD. Interestingly, LRA and step length collected from the NW session are similar to that of the healthy population.
  
  
  CONCLUSIONS
  This cross-sectional controlled study demonstrates that NW may constitute a powerful way to struggle against the randomness of PD gait and the typical gait hypokinesia. Involving a voluntary intersegmental coordination, such improvement could also be due to the upper body rhythmic movements acting as rhythmical external cue to bypass their defective basal ganglia circuitries.
  B403201318916 TRIAL REGISTRATION: NCT02419768.
authors.affiliation: Physical and Rehabilitation Medicine Department, Cliniques universitaires Saint-Luc, Avenue Hippocrate n°10, 1200, Brussels, Belgium. thibault.warlop@uclouvain.be.|Institut de Recherche Expérimentale et Clinique, Neuro Musculo Skeletal Lab (IREC/NMSK), Université catholique de Louvain, Brussels, Belgium. thibault.warlop@uclouvain.be.|Louvain Bionics, Université catholique de Louvain, Brussels, Belgium. thibault.warlop@uclouvain.be.
authors.forename: Thibault
authors.identifier: http://orcid.org/0000-0002-8837-4124
authors.initials: T
authors.lastname: Warlop
authors.affiliation: Institut de Recherche Expérimentale et Clinique, Neuro Musculo Skeletal Lab (IREC/NMSK), Université catholique de Louvain, Brussels, Belgium.|Louvain Bionics, Université catholique de Louvain, Brussels, Belgium.
authors.forename: Christine
authors.initials: C
authors.lastname: Detrembleur
authors.affiliation: Institut Parnasse-Deux Alice, Brussels, Belgium.
authors.forename: Maïté
authors.initials: M
authors.lastname: Buxes Lopez
authors.affiliation: Physical and Rehabilitation Medicine Department, Cliniques universitaires Saint-Luc, Avenue Hippocrate n°10, 1200, Brussels, Belgium.|Institut de Recherche Expérimentale et Clinique, Neuro Musculo Skeletal Lab (IREC/NMSK), Université catholique de Louvain, Brussels, Belgium.|Louvain Bionics, Université catholique de Louvain, Brussels, Belgium.
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Stoquart
authors.affiliation: Physical and Rehabilitation Medicine Department, Cliniques universitaires Saint-Luc, Avenue Hippocrate n°10, 1200, Brussels, Belgium.|Institut de Recherche Expérimentale et Clinique, Neuro Musculo Skeletal Lab (IREC/NMSK), Université catholique de Louvain, Brussels, Belgium.|Louvain Bionics, Université catholique de Louvain, Brussels, Belgium.
authors.forename: Thierry
authors.initials: T
authors.lastname: Lejeune
authors.affiliation: Institute of Neurosciences (IoNS), Université catholique de Louvain, Brussels, Belgium.|Neurology Department, Cliniques universitaires Saint-Luc, Brussels, Belgium.
authors.forename: Anne
authors.initials: A
authors.lastname: Jeanjean
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D003463:Cues; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000534:rehabilitation; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000534:rehabilitation*; D011597:Psychomotor Performance / Q000502:physiology; D016138:Walking
keywords: Accelerometers; Fractals; Gait disorders; Gait variability; Hypokinesia; Locomotion; Nonlinear dynamics; Parkinson's disease; Rehabilitation