Dynamic Factor Analysis of Seasonal Variation in Daily Physical Activity in Individuals with Heart Failure and Implanted Cardiac Devices

PURPOSE: Improving daily physical activity (PA) is an important clinical outcome in individuals with heart failure (HF) in regard to prognosis and mortality. Seasonal variation may confound studies investigating interventions to improve daily PA, although the presence and magnitude of seasonal variation has yet to be established in this population. The purpose of the present study was to determine the presence and magnitude of seasonal variation in daily physical activity (PA) in those with heart failure. SUBJECTS: 435 patients managed by Spectrum Health Cardiac Device Clinic in West Michigan with HF and Medtronic implanted cardioverter defibrillator and cardiac resynchronization devices (ICD/CRTs) with daily PA data between November 1, 2016-October 31, 2017 were included. METHODS AND MATERIALS: The present study was retrospective. Medtronic ICD/CRT devices with a single-axis accelerometer recorded daily PA. Local/in-system electronic health record data was utilized for inclusion and exclusion of patients. Meteorological data was obtained from the Local Climate Dataset. ANALYSES: Dynamic factor analysis (DFA) of Patient Activity data from Medtronic ICD/CRTs was utilized to identify common states/trends in multivariate PA time series data, while accounting for clinical characteristics/explanatory covariates and meteorological data/covariates. Univariate analyses were used to compare patient groups based upon relevant clinical characteristics identified by the DFA. RESULTS: In the data set of 435 patients, distinct states/trends were identified by DFA, which were associated with specific clinical characteristics. These trends included both a classic, sinusoidal pattern of seasonal variation for some patients, and a pattern of decline over the course of the year for others. CONCLUSIONS: Those with HF and Medtronic ICD/CRTs with low comorbidities, better NYHA Class, higher BMI, no hospitalization, and male sex demonstrated greater seasonal variation of at least 40 minutes per day. Those with HF and Medtronic ICD/CRTs with female sex and hospitalization demonstrated overall downward trajectories of approximately 40 and 80 minutes, respectively, over the course of the year

Dynamic Measures of Balance during a 90° Turn in Self-Selected Gait in Individuals with Mild Parkinson’s Disease

The risk of falls is common in the aging and Parkinson’s disease (PD) populations. There is limited research on dynamic gait stability, i.e., margin of stability (MOS), in the PD population while turning. The purpose of this exploratory study was to examine the dynamic balance control in individuals with mild to moderate PD and healthy individuals while walking and performing 90° turns utilizing computerized three-dimensional gait analysis. Specifically, we examined the anteroposterior and mediolateral margins of stability and their effect on the dynamic balance during turning in participants. A total of 11 individuals with mild to moderate idiopathic PD and 10 healthy controls (CON) participated in this study. Individuals with PD were tested during the “on phase” of PD medication. The Vicon Nexus camera system, force plates, and Visual3D software were utilized for three-dimensional motion analysis of three right and three left turning trials. A mixed-model ANOVA was used to analyze the primary dependent variables of dynamic balance (p p < 0.0056). No significant differences in the spatiotemporal parameters or dynamic balance variables were observed between the groups. Gait velocity, center of mass-center of pressure (COM–COP) inclination angle at midstance, and MOS variables showed marginally significant group differences. We found no differences in dynamic balance during gait while performing turns betweenthe healthy elderly and individuals with PD. This finding may be related to the early stage of disease progression in the PD group