Exercise, Physical Therapy May Provide Long-Term Functional Improvement in Huntington Disease

Huntington disease (HD) affects an estimated 25,000 to 30,000 individuals in the United States, with an additional 150,000 to 250,000 estimated to be at risk of developing the disease.¹ There are currently no known therapies that can cure the disease or alter its progression, and the primary aim of pharmacologic treatment is to reduce the involuntary choreic movements that represent the hallmark symptom of HD. This strategy may improve quality of life, safety, and function for many patients.

An increasing number of studies over the past decade have focused on the potential benefits of exercise and physical therapy in this patient population. “Exercise interventions aimed at improving the range of motor and cognitive impairments in people with HD may provide a long-term beneficial effect to maximize functional abilities, maintain independence over a longer period and potentially impact the progression of the disease,” wrote the authors of a new paper on the topic published in the Journal of Huntington’s Disease.²

Noting the need for rigorous, evidence-based clinical guidelines pertaining to the use of such interventions in HD, the authors used the Joanna Briggs Institute (JBI) approach to conduct a mixed-methods systematic review of research that evaluated physical therapy or exercise interventions in HD. Research included in the review covered various types of exercise interventions, including aerobic exercise, strengthening exercise, balance training, functional exercise, video game-based exercise, and assistive device training. The most common intervention was a combination of aerobic and strengthening exercises.

Their search included studies published between 2003, when the last systematic review on the topic was published,³ and 2016. The final review consisted of 18 quantitative studies that included a wide range of outcome measures for physical and cognitive function, and 2 qualitative studies that identified patient and family perceptions of the interventions. Most of the studies were conducted in Europe and published between 2013 and 2016. Three studies each were conducted in the United States and Australia. There was a combined total of 441 participants.

The most significant findings are summarized below.

• Motor function and performance. Three of 5 studies, which used either the United Huntington’s Disease Rating Scale-Total Motor Score (UHDRS-TMS) or the modified Motor Score (mMS), demonstrated statistically significant improvements in motor scores.^4-6
• Gait speed. Four of 7 studies investigated the effect of exercise or physical therapy on gait speed using either the 10-meter walk test or the 5-meter GAITRite® instrumental mat. Statistically significant improvements were observed in 4 of the studies, one of which was a randomized controlled trial⁴ and 3 of which had a pre/post design.^7-9
• Balance. Of 7 studies that examined balance as a secondary outcome, one showed greater improvement on the Romberg test in the intervention group vs controls.¹⁰ In several other studies, patients maintained or improved on Berg Balance Scale scores following intervention.^7-9,11 Of 4 studies that examined balance confidence as a secondary outcome, one found improvements on the Activities Balance Confidence scale for both walking and stairs in the intervention group, while scores in the control group declined.⁵