Short-term effects of postural control by standing on a tilting board in patients with Parkinson's disease

Background: People with Parkinson's disease (PD) often have backward displacement of their center of pressure (COP) during quiet standing and reduced stability limits, as compared to healthy controls. These kinetic characteristics may induce postural instability in people with PD.Objective: To investigate the short-term effects on COP displacements during quiet standing and forward leaning brought about by the post-incline leaning after-effects in people with PD.Methods: Twenty participants with PD were randomly divided into two groups (tilting and control groups). The tilting group was required to stand upright quietly on a tilting board angled to raise the front part of the feet. The control group was asked to voluntarily lean their bodies forward as far as possible. The total time of the intervention was 60 seconds for each group. The COP displacements during quiet standing and forward leaning were recorded before and after the intervention.Results: In the tilting group, the COP significantly shifted forward after the intervention compared to that before the intervention during quiet standing as well as forward stability limits; this did not happen in the control group.Conclusions: The post-incline leaning after-effects may induce the short-term effects of forward shifting of COP during quiet standing and expand the forward stability limits in people with PD.