Correlation Between Functional Balance and Mobility Tests and Postural Sway Measures in Dual Task Paradigm in Parkinson’s Disease (a Pilot Study)

Objective: The present study was aimed to correlate the clinical tests with the laboratory measures under dual task conditions in Parkinson's disease (PD). Materials and Methods: Eleven people with idiopathic PD (Modified Hoehn and Yahr scores 1-3) were selected by simple non-probability sampling. Center of pressure (COP) data obtained by force platform was used to calculate mean total velocity, standard deviation (SD) of amplitude along anterior-posterior (A.P) and medial-lateral (M.L) directions, path length and total phase plane in four levels of postural difficulty (quiet standing on rigid and foam surface with open and closed eyes) and two levels of cognitive difficulty (with and without cognitive task). Functional Reach (FR), Timed UP and Go (TUG), Berg Balance Scale (BBS), and gait speed tests were used for clinical assessment. Results: There was no significant correlation between FR and TUG test and any of COP parameters in different levels of postural and cognitive difficulty. Among different COP parameters, SD of amplitude (A.P) in standing on rigid surface with closed eyes without cognitive task and in standing on foam with closed eyes and cognitive task showed moderate to high correlation with BBS. Also significant correlation was seen between the SD of amplitude (A.P) in standing on foam with open eyes without cognitive task and gait speed test. Conclusion: No correlation was seen between Laboratory and clinical measures, indicating that they might evaluate different dimensions of balance control in PD.