Feasibility, Reliability, and Validity of the Timed Functional Arm and Shoulder Test Among Individuals With Parkinson's Disease

Purpose: To examine the feasibility, test-retest reliability, and validity of the Timed Functional Arm and Shoulder Test (TFAST) with individuals with PD. Method: Twenty-six participants with PD were examined using TFAST; Disability of the Arm, Shoulder, and Hand (DASH); and Movement Disorder Society Unified Parkinson Disease Rating Scale (UPDRS) Motor subscale. TFAST was readministered 2-7 days after baseline. Correlation analysis examined relationships between the measures. Participants' TFAST scores were compared with those of asymptomatic older adults. Results: Of participants, 96.2% completed TFAST. Reliability was characterized by an intra-class correlation coefficient (2,1) of 0.93 (95% CI: 0.84, 0.97). TFAST and UPDRS correlated weakly (r = -0.19, 95% CI: -0.55, 0.22) and TFAST and DASH (r = -0.36, 95% CI: -0.66, 0.04), and UPDRS and DASH (r = 0.46, 95% CI: 0.08, 0.72) correlated moderately. Participants with PD had lower TFAST scores than older adults (mean difference 18.8, 95% CI: 6.0, 31.6, p = 0.005). Conclusions: TFAST appears feasible and highly reliable with people with PD. Moderate correlations between the measures suggest each provides unique insight into disability. TFAST scores of people with PD were significantly lower than those of asymptomatic older adults with less upper extremity disability.