Evaluation of the Motus wearable sensor based system to accurately classify postures and movements in 3-14 aged children

Abstract

Background Robust measurements of children’s postures and movements are required to understand their impact on health and wellbeing. Recent advances in wearable sensor technology may enable the development of accurate measurements. Motus, a wearable sensor based system for surveillance of postures and movements, has shown high accuracy among adults. However, its accuracy to measure postures and movements among children is unknown. This study aimed to evaluate the criterion validity of Motus to measure common postures and movements among children between 3–14 years old in a laboratory setting. We further assessed if the sex or age of children impacted accuracy. Method Data were collected on 48 children who attended a structured ~ 1-hour data collection session at a Curtin University laboratory with their caregivers. The session was video recorded and thigh acceleration was measured using a SENS accelerometer. Data from the accelerometer were processed and classified into nine postures and movements using the Motus software. Human-coded video provided the ground truth to calculate sensitivity, specificity, precision, F1-scores, and balanced accuracy. Results We observed good to very good overall accuracy (F1-score = 61.9, balanced accuracy = 81.1%) and for classifying lying, sitting, standing (ranging between 63.2–85.3%). Walking and running were classified with moderate to very good accuracy. The lowest accuracy was observed for classifying stair climbing. We found a higher accuracy for stair climbing among girls compared to boys and for older compared to younger age-groups for walking, running and stair climbing. Conclusion Motus showed moderate to very good accuracy for detecting lying, sitting, standing, and running among children. The system could be improved for classifying the more dynamic postures and movements (i.e. walking, running and stair climbing), particularly among younger children and developed further to measure more child-specific postures and movements.