Task-Specific Training in Huntington Disease: A Randomized Controlled Feasibility Trial

Background. Task-specific training may be a suitable intervention to address mobility limitations in people with Huntington disease (HD). Objective. The aim of this study was to assess the feasibility and safety of goal-directed, task-specific mobility training for individuals with mid-stage HD. Design. This study was a randomized, blinded, feasibility trial; participants were randomly assigned to control (usual care) and intervention groups. Setting. This multisite study was conducted in 6 sites in the United Kingdom. Patients. Thirty individuals with mid-stage HD (13 men, 17 women; mean age = 57.0 years, SD = 10.1) were enrolled and randomly assigned to study groups. Intervention. Task-specific training was conducted by physical therapists in participants' homes, focusing on walking, sit-to-stand transfers, and standing, twice a week for 8 weeks. Goal attainment scaling was used to individualize the intervention and monitor achievement of personal goals. Measurements. Adherence and adverse events were recorded. Adjusted between-group comparisons on standardized outcome measures were conducted at 8 and 16 weeks to determine effect sizes. Results. Loss to follow-up was minimal (n = 2); adherence in the intervention group was excellent (96.9%). Ninety-two percent of goals were achieved at the end of the intervention; 46% of the participants achieved much better than expected outcomes. Effect sizes on all measures were small. Limitations. Measurements of walking endurance were lacking. Conclusions. The safety of and excellent adherence to a home-based, task-specific training program, in which most participants exceeded goal expectations, are encouraging given the range of motivational, behavioral, and mobility issues in people with HD. The design of the intervention in terms of frequency (dose), intensity (aerobic versus anaerobic), and specificity (focused training on individual tasks) may not have been sufficient to elicit any systematic effects. Thus, a larger-scale trial of this specific intervention does not seem warranted.