Statistical analysis Two-sample t-tests, Wilcoxon Rank-Sum, or Fisher's Exact tests were used to compare baseline features and exercise characteristics and outcomes between different treatment arms, and between the completers and dropouts, and to compare baseline cognitive performance of our PD participants with controls from our driving studies.[Uc, Rizzo, Johnson, Dastrup, Anderson, and Dawson2009] Regression methods were used to adjust these comparisons for age, education, and gender.