Huntington’s disease (HD) is an inherited, progressive, neurodegenerative disease that leads to movement, psychiatric, and cognitive symptoms. There is no cure for this debilitating disease, hence the importance of developing effective interventions with the potential to delay disease onset. Despite encouraging results from HD mice model studies, suggesting that environmental stimulation can delay degenerative loss and the onset of motor symptoms and may enhance treatment effects of graft transplants, there is little research into cognitive-behavioural training in HD. Recently, we carried out a NMHRI seedcorn funded pilot study into the feasibility of a novel drumming training designed to exercise working memory functions that are affected early in HD. The results suggest improvements in executive functioning and diffusion tensor imaging (DTI) based indices of white matter microstructure in frontal/motor pathways after two months of training. Although encouraging, these results are preliminary since the pilot was only based on a small number of patients and did not include a control group. Thus, the purpose of the present study is to replicate and expand these findings to address questions of training specificity and the mechanisms behind structural white matter changes, by employing novel MRI techniques that specifically measure axon myelination and density.