<qa>  What is the primary and secondary therapeutic outcome of the study?Analysis relevant to the secondary aim of the study will be conducted as follows: Baseline to endpoint changes in therapeutic outcomes, cognitive-behavioral measures and blood assay values will be compared across treatment arms using appropriate statistical tests. Baseline to endpoint changes in standing balance and gait parameters will be analyzed using methods that are standard in the current literature. In addition to appropriate statistical tests, these include the visual inspection of graphic displays of the phase relationships between rotational movements of body segments during gait. The association between each mechanistic parameter - cognitive-behavioral, biomechanical, and blood biomarkers - and the primary and secondary therapeutic outcomes will be explored per treatment arm and in aggregate. 