Relationship between symmetry index and postural sway parameters in dynamic task and functional balance tests in right and left hemiparesis patients (pilot study)

Independence in bending and picking up an object from the floor has great importance in activities of daily living. Asymmetrical distribution of weight is effective factor in imbalance and postural instability in people with hemiparesis. This study aimed to investigate the correlation between symmetry index and postural sway in selected dynamic task and functional balance tests in people with right and left chronic hemiparesis. Seventeen hemiparetic patients (6 right، 11 left) were selected by simple non-probability sampling. Weight bearing symmetry was measured by two weight scales. Postural sway parameters of the dynamic tasks were examined by force platform and Functional Reach and Timed Up and Go tests were used to measure functional balance. Average for a value (standard deviation) for the months after stroke in right and left hemiparesis were 49. 33 (43. 06) and 75. 36 (91. 13) respectively. Symmetry index showed high to very high correlation (r = 0. 865-0. 925) with average COP velocity in right-far target and with total path excursion of COP in all near targets and right-far target in right hemiparesis and high correlation (r = -0. 716) with maximum COP displacement in anterior-posterior direction in left-near target in left hemiparesis. Similarly، high correlation (r = -0. 716) was found with maximum COP displacement in anterior-posterior direction in left-near target in left hemiparesis. Also it had no significant correlation with maximum COP displacement in anterior-posterior direction in right hemiparesis and with maximum COP displacement in medial-lateral direction in left hemiparesis. Symmetry index had a moderate correlation (r = -0. 623) with Functional Reach test in left-sided hemiparesis but had no correlation with balance tests in right-sided hemiparesis. Because of difference in symmetry index correlation with postural sway parameters in dynamic task and functional balance tests in right and left hemiparesis، it can be noted that these two groups use different strategies while doing this task.