Optimization and Validation of a Classification Algorithm for Assessment of Physical Activity in Hospitalized Patients.

Low amounts of physical activity (PA) and prolonged periods of sedentary activity are common in hospitalized patients. Objective PA monitoring is needed to prevent the negative effects of inactivity, but a suitable algorithm is lacking. The aim of this study is to optimize and validate a classification algorithm that discriminates between sedentary, standing, and dynamic activities, and records postural transitions in hospitalized patients under free-living conditions. Optimization and validation in comparison to video analysis were performed in orthopedic and acutely hospitalized elderly patients with an accelerometer worn on the upper leg. Data segmentation window size (WS), amount of PA threshold (PA Th) and sensor orientation threshold (SO Th) were optimized in 25 patients, validation was performed in another 25. Sensitivity, specificity, accuracy, and (absolute) percentage error were used to assess the algorithm's performance. Optimization resulted in the best performance with parameter settings: WS 4 s, PA Th 4.3 counts per second, SO Th 0.8 g. Validation showed that all activities were classified within acceptable limits (>80% sensitivity, specificity and accuracy, ±10% error), except for the classification of standing activity. As patients need to increase their PA and interrupt sedentary behavior, the algorithm is suitable for classifying PA in hospitalized patients.

Monitoring daily physical activity of upper extremity in young and adolescent boys with Duchenne muscular dystrophy: A pilot study.

INTRODUCTION: Accelerometry of the upper extremity (UE) potentially provides information on the extent of activities in daily life in patients with Duchenne muscular dystrophy (DMD). The objective of this study is to evaluate the validity of home measurements of UE accelerometry. METHODS: This was a cross-sectional study in 16 patients with DMD (aged 7-17 years). Patients were monitored for 1 to 3 days with two accelerometers on the UE and one accelerometer on the wheelchair. RESULTS: The mean intensity of activity and the mean frequency of transfers of arm elevation from low to middle were approximately twofold higher in patients with a Brooke scale score of 1 or 2 than in patients with a Brooke scale score of 3 or 4. Correlations with the Performance of Upper Limb scale score were high for intensity and for the total frequency of arm elevations per hour. DISCUSSION: Intensity, percentage of time in middle orientation, and frequency of transfers of the upper arm correlated well with functional measurements.

Changes in physical activity and sedentary behaviour following pulmonary rehabilitation in patients with COPD.

A more profound investigation about the responses in activity levels following pulmonary rehabilitation (PR) in patients with COPD is needed. We aimed to describe groups of patients with COPD according to patterns of change in physical activity and sedentary behaviour following PR. 90 patients with COPD (60% male; mean age 67 ± 8; median FEV1 47 (32-62) %pred) completed a comprehensive PR programme. A triaxial accelerometer was used to assess the time in sedentary behaviour, light activities and moderate-to-vigorous physical activity (MVPA). Additionally, exercise capacity, quality of life, and symptoms of anxiety and depression were assessed before and after PR. Six groups with different patterns of change in physical activity and sedentary behaviour were identified. The two most prevalent patterns were represented by good responders (increase in physical activity and reduction in sedentary behaviour, 34%) and poor responders (decrease in physical activity and increase in sedentary behaviour, 30%). Good responders had greater improvements in six-minute walk distance (6MWD) and symptoms of depression than poor responders (P < 0.05 for all). Strong correlation was found between changes in sedentary behaviour and changes in light activities (rs = -0.89; P < 0.0001). Changes in 6MWD correlated fairly with changes in sedentary behaviour (rs = -0.26), light activities (rs = 0.25), and MVPA (rs = 0.24); P < 0.05 for all. Different patterns of change in activity levels following PR can be found in patients with COPD. Focusing on light physical activities might be a potential strategy to make patients less sedentary, but for this to be achieved prior (or at least parallel) improvements in functional capacity seem to be necessary.

Activity Levels and Exercise Motivation in Patients With COPD and Their Resident Loved Ones.

BACKGROUND: Resident loved ones of patients with COPD can play an important role in helping these patients engage in physical activity. We aimed to compare activity levels and exercise motivation between patients with COPD and their resident loved ones; to compare the same outcome measures in patients after stratification for the physical activity level of the loved ones; and to predict the likelihood of being physically active in patients with a physically active resident loved one. METHODS: One hundred twenty-five patient/loved one dyads were cross-sectionally and simultaneously assessed. Sedentary behavior, light activities, and moderate to vigorous physical activity (MVPA) were measured with a triaxial accelerometer during free-living conditions for at least 5 days. Five exercise-motivation constructs were investigated: amotivation, external regulation, introjected regulation, identified regulation, and intrinsic regulation. RESULTS: Patients spent more time in sedentary behavior and less time in physical activity than their loved ones (P < .0001). More intrinsic regulation was observed in loved ones compared with patients (P = .003), with no differences in other constructs. Despite similar exercise motivation, patients with an active loved one spent more time in MVPA (mean 31 min/d; 95% CI, 24-38 min/d vs mean, 18 min/d; 95% CI, 14-22 min/d; P = .002) and had a higher likelihood of being active (OR, 4.36; 95% CI, 1.41-13.30; P = .01) than did patients with an inactive loved one after controlling for age, BMI, and degree of airflow limitation. CONCLUSIONS: Patients with COPD are more physically inactive and sedentary than their loved ones, despite relatively similar exercise motivation. Nevertheless, patients with an active loved one are more active themselves and have a higher likelihood of being active. TRIAL REGISTRY: Dutch Trial Register (NTR3941).