The Effect of Sensory Reweighting on Postural Control in Parkinson's Disease

Research Objectives PD often results in impaired balance, which can significantly affect patients' quality of life. The Sensory Organization Test (SOT) is a balance assessment that evaluates the contributions of the visual, somatosensory, and vestibular systems to postural control. The aim of this study was to compare effect of sensory reweighting of these systems on postural control between participants with PD and HC. Design The SOT was designed to quantitatively evaluate ability of a person to maintain postural stability through visual, vestibular, and somatosensory inputs. We employed a VR Sensory Organization Test (VR-SOT) to evaluate postural balance; consisted of six trials, each lasting 20 seconds; (1) standing on a firm platform with eyes open; (2) standing on a firm platform in a dark environment; (3) standing on a firm platform with visual conflict; (4) standing on a foam with eyes open; (5) standing on foam in a dark environment; (6) standing on foam with visual conflict. Setting Participants completed VR-SOT while standing on a force plate. Center of Pressure (COP) displacement in the anteroposterior (AP) plane was the primary behavioral outcome. Participants This cross-sectional study included 10 participants with PD (age: 72 ± 9; 3 women; Hoehn&Yahr: 2 [1.5 – 2.50]) and 11 controls (age: 70 ± 3; 4 women). Interventions Linear mixed models were used to evaluate changes in COP displacement between two groups across the postural control conditions. Main Outcome Measures Using standing with eyes open as a reference, participants with PD exhibited a greater change in anteroposterior and mediolateral sway during Condition 5 and 6 compared to HC. Results PD group showed more AP sway when the vestibular system is being challenged. PD group showed more ML sway in all conditions (p=0.005). Conclusions Participants with PD show inadequate reweighting of postural control when the visual and somatosensory systems are challenged. This study's findings shed light on the mechanisms underlying balance impairments in PD and can inform future research and treatment approaches. Author(s) Disclosures Maryam Sadeghi, Thomas Bristow, Sodiq Fakorede, Rajesh Pahwa, Kelly Lyons, Hannes Devos