Improved Motor Function And Cortical Activation In Parkinson'S Disease Patients Following Acute Forced-exercise

Abstract

In previous studies, we have shown that a long-term lower extremity forced-exercise intervention (8 weeks) resulted in significant improvements in upper and lower extremity motor function of mild to moderate Parkinson's disease (PD) patients. The global nature of motor improvements suggest that forced-exercise may result in changes in central nervous system functioning. PURPOSE: To determine the motor and cortical effects of an acute bout of forced-exercise in a group of PD patients. METHODS: Motor function and functional magnetic resonance imaging (MRI) examinations were completed, in six mild to moderate PD patients, under two randomized conditions: no exercise and three hours after forced-exercise. The forced-exercise intervention consisted of one 40-minute session in which patients exercised on stationary tandem cycle with an able-bodied trainer. The trainer maintained a pedaling rate between 80-90 revolutions per minute which was approximately 35 percent faster than the patient's voluntary pedaling rate (60 revolutions per minute). Functional MRI analysis of changes in cortical activation volume was compared after forced-exercise to no exercise. RESULTS: Clinical motor function, assessed with the Unified Parkinson's disease Rating Scale-III, was nearly 40 percent better following forced-exercise compared to the no-exercise condition. During functional MRI scanning patients performed a force-tracking task in which they matched a projected sinusoidal or constant line. Motor performance was 35 percent better following forced-exercise compared to no exercise. Increases in cortical activation were most prominent in the supplementary motor area (SMA) after forced exercise in comparison to the no exercise state. This increase in activation was a general observation across tasks performed with each limb. CONCLUSION: Improvements in upper extremity function and increased levels of activation within cortical structures such as the SMA indicate that forced-exercise may facilitate central motor control processes in Parkinson's disease patients.