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Parkinson’s Disease
Volume 2013 (2013), Article ID 971480, 8 pages
Research Article

Which Aspects of Postural Control Differentiate between Patients with Parkinson’s Disease with and without Freezing of Gait?

Department of Rehabilitation Sciences, KU Leuven, Tervuursevest 101/1501, 3001 Leuven, Belgium

Received 11 February 2013; Revised 24 April 2013; Accepted 13 June 2013

Academic Editor: Leland E. Dibble

Copyright © 2013 Griet Vervoort et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This exploratory study aimed to identify which aspects of postural control are able to distinguish between subgroups of patients with Parkinson’s disease (PD) and controls. Balance was tested using static and dynamic posturography. Freezers ( ), nonfreezers ( ), and controls ( ) stood on a movable force platform and performed 3 randomly assigned tests: (1) sensory organization test (SOT) to evaluate the effective use of sensory information, (2) motor control test (MCT) to assess automatic postural reactions in response to platform perturbations, and (3) rhythmic weight shift test (RWS) to evaluate the ability to voluntarily move the center of gravity (COG) mediolaterally and anterior-posteriorly (AP). The respective outcome measures were equilibrium and postural strategy scores, response strength and amplitude of weight shift. Patients were in the “on” phase of the medication cycle. In general, freezers performed similarly on SOT and MCT compared to nonfreezers. Freezers showed an intact postural strategy during sensory manipulations and an appropriate response to external perturbations. However, during voluntary weight shifting, freezers showed poorer directional control compared to nonfreezers and controls. This suggests that freezers have adequate automatic postural control and sensory integration abilities in quiet stance, but show specific directional control deficits when weight shifting is voluntary.