The effect of fatigue on balance performance in Parkinson's disease

INTRODUCTION: Balance loss and falls are a common and multifactorial finding in persons with Parkinson's Disease (pwPD). Objective fatigability is thought to contribute to falls in other neurologic conditions, but its impact on balance in pwPD is not known. The two-fold purpose of this study was to: 1) establish that a 6-minute walk (6MW(Fast)) is a stimulus to subjective fatigue for pwPD; and, 2) determine if the Mini Balance Evaluation Systems Test (MBT) is sensitive to change that was induced by a fatiguing condition. METHODS: Using a randomized crossover design, 19 research participants performed a Mini Balance Evaluation Systems Test (MBT) before and after either a ‘fast’ 6-minute walk (6MW(Fast)) to induce fatigue or a 6-minute rest. RESULTS: VASF scores increased after the 6MW(Fast). Total MBT scores in research participants with Modified Hoehn and Yahr (H&Y) scores of 3.0 and above differed significantly before and after the ‘fast’ 6-minute walk (p = .007, n = 9) while participants with H&Y scores of 1.5 to 2.5 (p = .084, n = 10) did not, suggesting that more disabled pwPD were more likely to experience fatigability that interfered with balance. CONCLUSIONS: A 6MW(Fast) is a sufficient stimulus to induce subjective fatigue in pwPD and to decrease total MBT scores for more disabled pwPD. Balance evaluations should occur when pwPD are in fatigued and unfatigued states to determine whether fatigue has an impact on balance performance.