Validation of ActiGraph and Fitbit in the assessment of energy expenditure in Huntington's disease.

BACKGROUND: Consumer and research activity monitors have become popular because of their ability to quantify energy expenditure (EE) in free-living conditions. However, the accuracy of activity trackers in determining EE in people with Huntington's Disease (HD) is unknown. RESEARCH QUESTION: Can the ActiGraph wGT3X-B or the Fitbit Charge 4 accurately measure energy expenditure during physical activity, in people with HD compared to Indirect Calorimetry (IC) (Medisoft Ergo Card)? METHODS: We conducted a cross-sectional, observational study with fourteen participants with mild-moderate HD (mean age 55.7 ± 11.4 years). All participants wore an ActiGraph and Fitbit during an incremental test, running on a treadmill at 3.2 km/h and 5.2 km/h for three minutes at each speed. We analysed and compared the accuracy of EE estimates obtained by Fitbit and ActiGraph against the EE estimates obtained by a metabolic cart, using with Intra-class correlation (ICC), Bland-Altman analysis and correlation tests. RESULTS: A significant correlation and a moderate reliability was found between ActiGraph and IC for the incremental test (r = 0.667)(ICC=0.633). There was a significant correlation between Fitbit and IC during the incremental test (r = 0.701), but the reliability was poor at all tested speeds in the treadmill walk. Fitbit significantly overestimated EE, and ActiGraph underestimated EE compared to IC, but ActiGraph estimates were more accurate than Fitbit in all tests. SIGNIFICANCE: Compared to IC, Fitbit Charge 4 and ActiGraph wGT3X-BT have reduced accuracy in estimating EE at slower walking speeds. These findings highlight the need for population-specific algorithms and validation of activity trackers.

Pharmacogenetics in the Treatment of Huntington's Disease: Review and Future Perspectives.

Huntington's disease (HD) is an autosomal dominant progressive brain disorder, caused by a pathological expansion of a CAG repeat that encodes the huntingtin gene. This genetic neurodegenerative rare disease is characterized by cognitive, motor, and neuropsychiatric manifestations. The aim of the treatment is symptomatic and addresses the hyperkinetic disorders (chorea, dystonia, myoclonus, tics, etc.) and the behavioural and cognitive disturbances (depression, anxiety, psychosis, etc.) associated with the disease. HD is still a complex condition in need of innovative and efficient treatment. The long-term goal of pharmacogenetic studies is to use genotype data to predict the effective treatment response to a specific drug and, in turn, prevent potential undesirable effects of its administration. Chorea, depression, and psychotic symptoms have a substantial impact on HD patients' quality of life and could be better controlled with the help of pharmacogenetic knowledge. We aimed to carry out a review of the available publications and evidence related to the pharmacogenetics of HD, with the objective of compiling all information that may be useful in optimizing drug administration. The impact of pharmacogenetic information on the response to antidepressants and antipsychotics is well documented in psychiatric patients, but this approach has not been investigated in HD patients. Future research should address several issues to ensure that pharmacogenetic clinical use is appropriately supported, feasible, and applicable.

Accelerometer Cut-Points for Physical Activity Assessment in Adults with Mild to Moderate Huntington's Disease: A Cross-Sectional Multicentre Study.

Accelerometers can estimate the intensity, frequency, and duration of physical activity in healthy adults. Although thresholds to distinguish varying levels of activity intensity using the Actigraph wGT3X-B have been established for the general population, their accuracy for Huntington's disease (HD) is unknown. We aimed to define and cross-validate accelerometer cut-points for different walking speeds in adults with mild to moderate HD. A cross-sectional, multicentre, case-control, observational study was conducted with a convenience sample of 13 symptomatic ambulatory HD participants. The accelerometer was placed around the right hip, and a heart monitor was fitted around the chest to monitor heart rate variability. Participants walked on a treadmill at three speeds with light, moderate and vigorous intensities. Correlation and receiver operation curve analyses were performed between the accelerometer magnitude vector with relative oxygen and heart rate. Optimal cut-points for walking speeds of 3.2 km/h were ≤2852; 5.2 km/h: >2852 to ≤4117, and in increments until their maximum velocity: >4117. Our results support the application of the disease-specific cut-points for quantifying physical activity in patients with mild to moderate HD and promoting healthy lifestyle interventions.

Energy Balance in Huntington's Disease.

INTRODUCTION: Little is known about the energy needs in Huntington's disease (HD). The aims of this study are to analyze and compare the total energy expenditure (TEE) and energy balance (EB) in a representative sample of HD patients with healthy controls. METHODS: This is an observational, case-control single-center study. Food caloric energy intake (EI) and TEE were considered for estimating EB. A dietary recall questionnaire was used to assess the EI. TEE was computed as the sum of resting energy expenditure (REE), measured by indirect calorimetry and physical activity (PA) monitored by an actigraph. RESULTS: A total of 22 patients were included (36% men, mean age 50.3 ± 15.6 years, motor Unified Huntington's Disease Scale 27.9 ± 23.7, total functional capacity 11.0 (7.0-13.0), EI 38.6 ± 10.0 kcal/kg, PA 5.3 (3.0-7.4) kcal/kg, REE 30.9 ± 6.4 kcal/kg, TEE 2,023.4 (1,592.0-2,226.5) kcal/day) and 18 controls (50% men, mean age 47.4 ± 13.8 years, EI 38.6 ± 10.3 kcal/kg, PA 8.4 (5.0-13.8) kcal/kg, REE 30.8 ± 6.6 kcal/kg, TEE 2,281.0 (2,057.3-2,855.3) kcal/day). TEE was significantly lower in patients compared to controls (p = 0.03). PA was lower in patients compared to controls (p = 0.02). CONCLUSIONS: Although patients with HD appeared to have lower energy expenditure, mainly due to decreased voluntary PA, they were still able to maintain their energy needs with an adequate food intake. © 2015 S. Karger AG, Basel.