RR-PL-2011

Thursday 10:00, Fira Palace Hotel, Vivaldi

ANALYSIS OF THE SIT TO STAND TASK IN PERSONS WITH PARKINSON’S DISEASE. Pathare N, Brunt D, Bishop MB, Ko MS, Lyons JM, Smith L; Departments of Physical Therapy and Neurology, University of Florida, Gainesville, USA. PURPOSE: To study the sit to stand (STS) task in persons with Parkinson’s disease (PD). RELEVANCE: The STS task is a major determinant for independence and quality of life for persons with PD. 44.2 % of persons with PD have difficulty during STS and it is an important risk factor for falls in PD. Analyzing different strategies used by patients with PD to accomplish STS will provide insight into functional capabilities and designing therapeutic interventions. SUBJECTS: Subjects with PD on levodopa medication (n = 22, mean age = 63.25 years, mean Hoehn and Yahr = 2.17, mean UPDRS Motor score = 20.5) and healthy elderly subjects (n =12, mean age = 66.07 years) participated in this study. METHODS AND MATERIALS: Subjects were asked to stand up from a bench (height adjusted to place knees in 90º) .Two force plates situated on the floor measured peak acceleration (Fx) and vertical (Fz) ground reaction forces and slopes to peaks as well as temporal events of STS. Surface electrodes were applied to the tibialis anterior (TA) and soleus (SOL) of both limbs to measure onset of TA and reciprocal inhibition of SOL. ANALYSES: Based on time to complete STS (time to peak Fz), we divided subjects with PD into two groups: Group A (n= 12, mean time: 695.43 ms) and Group B (n= 10, mean time: 919.28 ms). ANOVA was used to make comparisons between these two groups and elderly with type I error at 0.05. RESULTS: Significant main effects were noted for time to seat off, time to STS, slope to Fx and slope to Fz. Post hoc tests showed that Group B took longer time to stand up and seat off, and produced Fx and Fz forces at slower rates than Group A and the elderly subjects. No differences existed between Group A and elderly subjects. 30 % of subjects in Group B did not activate their TA at movement onset while 95.83% of subjects in Group A and all the elderly subjects were able to do so. Reciprocal inhibition of SOL was noted in almost all the subjects in the three groups. CONCLUSION: Subjects with PD who took longer to perform STS did so due to a longer time for seat off and generated acceleration forces and vertical forces at slower rates. Deficits to recruit TA may attribute to decreased rate of production of the acceleration forces and the longer time required for seat off. Hypokinesia is related to decreased rates of force in upper extremity. This is likewise the case in the STS task. Decreased rate of rise of force is used to identify fallers in the elderly and subjects with stroke. Decreased rates of force production may assist in identifying those at risk of falls amongst those with PD and may imply greater functional impairment in performance of the STS task in them.