Should gait speed be included in the clinical evaluation of Parkinson’s disease?

Abstract

Background: The Unified Parkinson’s Disease Rating Scale is the most commonly used scale in the clinical study of Parkinson’s disease. However, it may fail to capture the essence of physical impairment in patients with Parkinson’s disease and thus limit responsiveness of care-givers, patients, and/or clinicians as to increasing physical disability. This study sought to compare subjective measures of physical disability in Parkinson’s disease to an objective, accurate, and proven measure of physical function-gait speed. Methods: Eighty-eight individuals with early to moderate stage Parkinson’s disease were evaluated on the Unified Parkinson’s Disease Rating Scale, the Parkinson’s disease Questionnaire 39 and during five 8 meter walking trials. Spearman correlations coefficients were used to determine the association among all variables of interest. Results: The findings demonstrate that only a fair to moderate relationship between objectively measured gait speed and physical function as measured subjectively by the clinical rating scale and as evaluated by the patients during self report. Conclusions: The results of this study suggest that commonly utilized measures of physical function in Parkinson’s disease are not highly correlated with gait speed. Because gait speed is demonstrated as a dependable proxy for physical function, the results of this study may provide a rational for the use of gait speed to provide a more accurate picture of physical function in patients with Parkinson’s disease.