A comparative study of physical performance measures in Parkinson's disease.

UNLABELLED: The objective of this study is to compare physical performance measures for their ability to discriminate between levels of disability and disease severity in Parkinson's disease (PD). Disability in PD is commonly assessed by patient self-report, which may be limited by patient insight.

METHODS: Seventy-nine patients with PD were tested with seven performance measures: Physical Performance Test (PPT), modified Physical Performance Test (mPPT), Short Physical Performance Battery (SPPB), Performance Test of Activities of Daily Living (PADL), Berg Balance Scale (BBS), Timed Up and Go (TUG), and Functional Reach (FR). These measures were compared with patient-reported disability on the Older Americans Resource and Services Disability subscale (OARS) and disease severity on the Unified Parkinson's Disease Rating Scale (UPDRS). The performance measures were more sensitive to levels of disease severity than disability. Four measures discriminated across quartiles of disability (PPT, mPPT, BBS, TUG: P < 0.05), whereas all seven measures discriminated across quartiles of the Total UPDRS (PPT, mPPT, BBS, TUG, FR: P < 0.01; SPPB, PADL: P < 0.05). However, no measure consistently discriminated between subgroups with a range of early and advanced disease severity. The seven physical performance measures showed different profiles of strengths and weaknesses in assessing disability and disease severity. The results of this study will facilitate choosing performance measures for clinical care and clinical trials in PD.