Statistical learning of mobility patterns from long-term monitoring of locomotor behaviour with body-worn sensors

Evidence-based yet still challenging! Research on physical activity in old age

Preserving functional health and quality-of-life in old age is a major goal and global challenge in public health. The high rate of sedentary behavior that is characteristic of the older adult population exacerbates impairments of physiological and structural systems that are typically seen in the aging process. Achieving an understanding of the profound influence of physical activity on all aspects of health in old age is the driving force behind the emergence of "physical activity in old age" as a growing area of research. Accumulated evidence implies that being physically active and exercising is far superior to other optimal aging facilitators. Yet this area of research faces numerous constraints and obstacles. This commentary addresses some of these challenges, primarily the heterogeneity of the aging process, which induces both inter- and intra-individual differences among aged individuals, heterogeneity in assessment tools, unjustified inclusion/exclusion criteria and insufficient recruitment strategies, difficulties in implementing research results in real-world conditions, and rudimentary exploitation of innovative technology. We explain the importance of establishing a network of multidisciplinary scientists and stakeholders to propose consensus-based goals and scientifically evidenced wide-ranging plans for dealing with these challenges. In addition, we suggest work directions for this network.

Quantifying Habitual Physical Activity and Sedentariness in Older Adults-Different Outcomes of Two Simultaneously Body-Worn Motion Sensor Approaches and a Self-Estimation

Applicable and accurate assessment methods are required for a clinically relevant quantification of habitual physical activity (PA) levels and sedentariness in older adults. The aim of this study is to compare habitual PA and sedentariness, as assessed with (1) a wrist-worn actigraph, (2) a hybrid motion sensor attached to the lower back, and (3) a self-estimation based on a questionnaire. Over the course of one week, PA of 58 community-dwelling subjectively healthy older adults was recorded. The results indicate that actigraphy overestimates the PA levels in older adults, whereas sedentariness is underestimated when compared to the hybrid motion sensor approach. Significantly longer durations (hh:mm/day) for all PA intensities were assessed with the actigraph (light: 04:19; moderate to vigorous: 05:08) when compared to the durations (hh:mm/day) that were assessed with the hybrid motion sensor (light: 01:24; moderate to vigorous: 02:21) and the self-estimated durations (hh:mm/day) (light: 02:33; moderate to vigorous: 03:04). Actigraphy-assessed durations of sedentariness (14:32 hh:mm/day) were significantly shorter when compared to the durations assessed with the hybrid motion sensor (20:15 hh:mm/day). Self-estimated duration of light intensity was significantly shorter when compared to the results of the hybrid motion sensor. The results of the present study highlight the importance of an accurate quantification of habitual PA levels and sedentariness in older adults. The use of hybrid motion sensors can offer important insights into the PA levels and PA types (e.g., sitting, lying) and it can increase the knowledge about mobility-related PA and patterns of sedentariness, while actigraphy appears to be not recommendable for this purpose.

Day-to-day variability of multiple sensor-based physical activity parameters in older persons with dementia

OBJECTIVE

To investigate the day-to-day variability of various sensor-based physical activity (PA) parameters and to analyze effects of weekdays vs. weekend days as well as the influence of concomitant factors (gender, living conditions, cognitive status, physical performance, and level of PA) in multi-morbid, older persons with mild-to-moderate stage dementia.

METHODS

In 53 participants, PA was recorded on three consecutive days. Day-to-day variability was estimated by calculating intraclass correlation coefficients (ICCs) for two consecutive days each (Friday-Saturday, Saturday-Sunday).

RESULTS

Almost all non-walking parameters (lying time, sitting time, standing time, active time, inactive time, and sit-to-stand transitions) showed a consistently low day-to-day variability for Friday-Saturday as well as Saturday-Sunday (ICCs: .60-.96) and hence remained almost unaffected by specific days of the week and concomitant factors. Only the sub-analysis by level of PA revealed slightly deviating results (ICCs: .38-.89). The walking parameters (walking time, walking episodes, and steps) revealed a higher day-to-day variability for Friday-Saturday (ICCs: .01-.40) and a generally lower variability for Saturday-Sunday (ICCs: -.08 - .88), also depending on the respective concomitant factors.

CONCLUSIONS

Two consecutive days are adequate to reliably assess non-walking parameters, whereas walking parameters showed higher day-to-day variability with a relevant influence of type of days and concomitant factors.