title: Compensatory postural adjustments in Parkinson's disease assessed via a virtual reality environment.
abstract: Postural control is a complex dynamic mechanism, which integrates information from visual, vestibular and somatosensory systems. Idiopathic Parkinson's disease (IPD) patients are unable to produce appropriate reflexive responses to changing environmental conditions. Still, it is controversial what is due to voluntary or involuntary postural control, even less what is the effect of levodopa. We aimed to evaluate compensatory postural adjustments (CPA), with kinematic and time-frequency analyzes, and further understand the role of dopaminergic medication on these processes. 19 healthy subjects (Controls) and 15 idiopathic Parkinson's disease (IPD) patients in the OFF and ON medication states, wearing IMUs, were submitted to a virtual reality scenario with visual downward displacements on a staircase. We also hypothesized if CPA would involve mechanisms occurring in distinct time scales. We subsequently analyzed postural adjustments on two frequency bands: low components between 0.3 and 1.5 Hz (LB), and high components between 1.5 and 3.5 Hz (HB). Vertical acceleration demonstrated a greater power for discriminating IPD patients from healthy subjects. Visual perturbation significantly increased the power of the HB in all groups, being particularly more evident in the OFF state. Levodopa significantly increased their basal power taking place on the LB. However, controls and IPD patients in the ON state revealed a similar trend of the control mechanism. Results indicate an improvement in muscular stiffness provided by levodopa. They also suggest the role of different compensatory postural adjustment patterns, with LB being related to inertial properties of the oscillating mass and HB representing reactions to the ongoing visual input-changing scenario.
authors: Algoritmi Center, Department of Industrial Electronics, School of Engineering, University of Minho, Braga, Portugal.
authors: Darya
authors: D
authors: Yelshyna
authors: Neurology Department, Centro Hospitalar do Alto Ave, EPE, Guimarães, Portugal; Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal; ICVS-3Bs PT Government Associate Laboratory, Braga/Guimarães, Portugal. Electronic address: miguelfgago@yahoo.com.
authors: Miguel F
authors: MF
authors: Gago
authors: Algoritmi Center, Department of Industrial Electronics, School of Engineering, University of Minho, Braga, Portugal.
authors: Estela
authors: E
authors: Bicho
authors: Algoritmi Center, Department of Industrial Electronics, School of Engineering, University of Minho, Braga, Portugal.
authors: Vítor
authors: V
authors: Fernandes
authors: Algoritmi Center, Department of Industrial Electronics, School of Engineering, University of Minho, Braga, Portugal.
authors: Nuno F
authors: NF
authors: Gago
authors: Algoritmi Center, Department of Industrial Electronics, School of Engineering, University of Minho, Braga, Portugal.
authors: Luís
authors: L
authors: Costa
authors: Algoritmi Center, Department of Industrial Electronics, School of Engineering, University of Minho, Braga, Portugal.
authors: Hélder
authors: H
authors: Silva
authors: Neurology Department, Centro Hospitalar do Alto Ave, EPE, Guimarães, Portugal.
authors: Maria Lurdes
authors: ML
authors: Rodrigues
authors: Algoritmi Center, Department of Industrial Electronics, School of Engineering, University of Minho, Braga, Portugal.
authors: Luís
authors: L
authors: Rocha
authors: Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal; ICVS-3Bs PT Government Associate Laboratory, Braga/Guimarães, Portugal.
authors: Nuno
authors: N
authors: Sousa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D015259:Dopamine Agents / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy / Q000503:physiopathology*; D004856:Postural Balance / Q000187:drug effects / Q000502:physiology*; D014584:User-Computer Interface
chemical_list: D015259:Dopamine Agents; D007980:Levodopa
keywords: Compensatory postural adjustments; Idiopathic Parkinson’s disease; Kinematics; Time-frequency distribution; Virtual reality