FUNCTIONAL REACH

Abstract

Purpose/Hypothesis: Functional reach (FR) of less than 25.4cm has predictive validity in identifying elderly frail subjects at risk for recurrent falls (when adjusted for age, Folstein mental score and depression). In contrast, this measure has not been shown to be a sensitive measure for identifying medicated individuals with Parkinson's disease (PD) who were at risk for recurrent falls. However, movement disorders associated with PD that predisposes these individuals to slips, trips, and falls, become exacerbated during the ‘off’ or coming ‘off’ medication conditions. The purpose of this study was to determine the effect medication has on the predictive validity of FR in determining the risk of recurrent falls in individuals with PD. Number of Subjects: Forty subjects with PD were tested both off medication (12-hour overnight withdrawal of anti-parkinsonian medications) and then after the subject's regular medication was resumed. Materials/ Methods: Subjects underwent a clinical evaluation, which consisted of the motor (part III) subclass of the Unified Parkinson's Disease Rating Scale (UPDRS) and the FR test. Individuals were also asked if they had experienced 1 or more falls in the past year. A fall was defined as an incident that resulted in the person unexpectedly coming to the ground. The FR test was administered according to the procedure established by Duncan and colleagues. Each subject performed 1 practice trail and 3 test trials. The mean difference between the initial position and the end position for the three trials was calculated as the FR. Data was analyzed using analysis of variance and regression analysis. The independent variables were medication status (off, on), the motor subsection of the UPDRS and history of falls. Dependent variable was FR. All levels of significance were designated at p < 0.05. Results: Individuals with PD exhibited greater FR and higher UPDRS scores in the ‘off’ as compared to ‘on’ medication condition. FR, as a measure of the risk for recurrent falls in the ‘off’ medication condition revealed a test sensitivity of 100% and test specificity of 74%. Further, there was a significant correlation (R = .79) between ‘off’ medication UPDRS score and FR. In contrast, in the ‘on’ medication condition test validity for the FR test (measure of the risk of recurrent falls) revealed a test sensitivity of 30% and test specificity of 100%.Further, no correlation (R = .30) was revealed between the ‘on’ medication UPDRS score and FR. Conclusions: FR measured in the off medication condition, can identify individuals with PD who are at risk for recurrent falls. This study also illustrates the differing conclusions that can be reached when these individuals are tested in the ‘off’ as compared to the ‘on’ medication condition. Clinical Relevance: FR in the ‘off’ medication condition is a simple test that clinicians may use to identify individuals with PD who are at risk for recurrent falls. Due to the progressive nature of PD, individuals who are identified at risk should be enrolled in a fall risk intervention program.