Comparing interventions and exploring neural mechanisms of exercise in Parkinson disease: A study protocol for a randomized controlled trial

Background: Effective treatment of locomotor dysfunction in Parkinson disease (PD) is essential, as gait difficulty is an early and major contributor to disability. Exercise is recommended as an adjunct to traditional treatments for improving gait, balance, and quality of life. Among the exercise approaches known to improve walking, tango and treadmill training have recently emerged as two promising therapies for improving gait, disease severity and quality of life, yet these two interventions have not been directly compared to each other. Prior studies have been helpful in identifying interventions effective in improving gait function, but have done little to elucidate the neural mechanisms underlying functional improvements. The primary objective of the proposed work is to compare the effects of three community-based exercise programs, tango, treadmill training and stretching, on locomotor function in individuals with PD. In addition, we aim to determine whether and how these interventions alter functional connectivity of locomotor control networks in the brain. Methods/Design: One hundred and twenty right-handed individuals with idiopathic PD who are at least 30 years of age will be assigned in successive waves to one of three community-based exercise groups: tango dancing, treadmill training or stretching (control). Each group will receive three months of exercise training with twice weekly one-hour group classes. Each participant will be evaluated at three time points: pre-intervention (baseline), post-intervention (3 months), and follow-up (6 months). All evaluations will include assessment of gait, balance, disease severity, and quality of life. Baseline and post-intervention evaluations will also include task-based functional magnetic resonance imaging (fMRI) and resting state functional connectivity MRI. All MRI and behavioral measures will be conducted with participants OFF anti-Parkinson medication, with behavioral measures also assessed ON medication. Discussion: This study will provide important insights regarding the effects of different modes of exercise on locomotor function in PD. The protocol is innovative because it: 1) uses group exercise approaches for all conditions including treadmill training, 2) directly compares tango to treadmill training and stretching, 3) tests participants OFF medication, and 4) utilizes two distinct neuroimaging approaches to explore mechanisms of the effects of exercise on the brain.