Current Controlled Trials ISRCTN11392629.

Background. Huntington's disease (HD) results in a range of cognitive and motor impairments

Purpose. Huntington's disease is an autosomal dominant neurodegenerative disease. Progressive physical, behavioural and cognitive impairments cause loss of independent function. Physical activity interventions are important components of comprehensive intervention strategies and may help alter the functional decline trajectory. Qualitative research has an important role to play in developing theoretically sound, well-defined physical activity interventions in Huntington's disease. Materials and methods. Eight focus groups were conducted with people with prodromal to late stage Huntington's disease, caregivers (family members/formal), and healthcare professionals. An analytical coding framework was developed from the data and Levanthal's self-regulation model to assist analysis. Results and Conclusions. Key themes were identified: evolving representations of Huntington's disease and physical activity; varying social environment of the person with Huntington's disease and the impact on physical activity; achieving physical activity participation while coping with the nuances of Huntington's disease. Levanthal's model facilitated understanding of physical activity experiences, however with progression, selfregulation of activities needs to become more collaborative with caregivers. A modified selfregulation model specific to physical activity in Huntington's disease is presented. Using a novel approach to generate new understanding of physical activity across the Huntington's disease lifespan facilitated development of an original and significant theoretical foundation to underpin development of a range of much needed physical activity and exercise interventions in Huntington's disease.

Background Exercise is emerging as an important aspect in the management of disease-related symptoms and functional decline in people with Huntington disease (HD). Long-term evaluation of physical activity and exercise participation in HD has yet to be undertaken. Objective The objective is to investigate the feasibility of a nested randomized controlled trial (RCT) alongside a longitudinal observational study of physical activity and exercise outcomes in people with HD. Design This will be a 12-month longitudinal observational study (n = 120) with a nested evaluation of a physical activity intervention (n = 30) compared with usual activity (n = 30) using a “trial within a cohort” design. Setting The study will take place in HD specialist clinics in Germany, Spain, and the United States, with intervention delivery in community settings. Participants The participants will have early-mid–stage HD and be participating in the Enroll-HD study. Intervention This will be a 12-month physical activity behavioral change intervention, delivered by physical therapists in 18 sessions, targeting uptake of aerobic exercise and increased physical activity. Measurements All participants (n = 120) will complete Enroll-HD assessments (motor, cognitive, behavioral, and quality of life) at baseline and at 12 months. Additional Physical ACtivity and Exercise Outcomes in Huntington Disease (PACE-HD) assessments include fitness (predicted maximal oxygen uptake [V  o2max]), self-reported and quantitative measures of physical activity, disease-specific symptoms, and walking endurance. RCT participants (n = 60) will complete an additional battery of quantitative motor assessments and a 6-month interim assessment. Enroll-HD data will be linked to PACE-HD physical activity and fitness data. Limitations The limitations include that the embedded RCT is open, and assessors at RCT sites are not blinded to participant allocation. Conclusion PACE-HD will enable determination of the feasibility of long-term physical activity interventions in people with HD. The novel “trial within a cohort” design and incorporation of data linkage have potential to reduce participant burden. This design could be applied to other neurological diseases and movement disorders where recruitment and retention are challenging.

Our findings confirm metabolic and cardiorespiratory deficits reduce exercise performance and affect recovery from an early stage in HD, with submaximal deficits related to phenotypic expression. Exercise capacity appears to be limited by an altered movement economy, thus clinicians should consider an altered exercise response and recovery may affect prescription in HD.