Detecting falls by analyzing angular momentum

The aim of the present pilot study is to investigate the hypothesis that fall detection systems based on sensors placed on the distal segments of the body are more effective than solution based on placing sensors on the trunk. To test this hypothesis, we observed the contribution of all body segments to the 3D angular momentum. Five healthy adults were enrolled for the experimental sessions. A set of 39 spherical markers was located on body landmarks and subjects underwent perturbed walking while a Motion Analysis System recorded 3D kinematics. From a biomechanical model, the angular momentum pattern related to each body segment was estimated. Data were post-processed with a threshold-based algorithm used to detect which among body segments allows detect as soon as possible and with limited false alarms the perturbation. Results showed that hands-forearms and chest-head are the most sensitive to external moments orientated along respectively the anterior-posterior and medio-lateral directions.