A Proof of Concept for a Wireless Ambulatory Weight Bearing Measurement System in Rehabilitation and Telerehabilitation Applications
Authors: Ariane Authier, Patrick Boissy, Jacques Beauvais, Rojean Fontaine
Venue: Proceedings of the Third IEEE International Conference on Wireless and Mobile Computing, Networking and Communications (2007)

Weight bearing is an important clinical variable for rehabili- tation specialists. The objectives of this proof of concept study were to design and build a wireless system for weight bearing measurement that would provide accurate dynamic and static measurements of plantar forces from multiple sites. The pro- posed system consists of two shoes instrumented with minia- ture load cells connected to ankle modules for wireless com- munication to a computer and signal conditioning. Force plates were used as the gold standard to evaluate the accuracy of the proposed system during quiet standing, walking and weight-shifting tasks in 30 young subjects. The performance of the system was characterized for each task using the following variables: percentage of body weight (PBW), heel-strike (HS) peak force value, stance time (ST), double support time (DST), excursion of center of pressure (COP) in the anteroposterior axis ( COPx). For the measurement of the PBW, the standard deviation of errors in comparison to data obtained from forces plates during quiet-standing and weight-shifting activities was between 3.96% and 5.13%. With respect to gait parameters, the standard deviation of errors for the measurement of the peak forces during walking was between 6.10% and 8.82% for both shoes, and errors on timing variables during gait cycles were small (less than 18 msec for one standard deviation). For the COPx during a front weight-shifting trial, the standard deviation of errors was 19.20% for the right foot. The accu- racy of the proposed system offers acceptable performances in the context of its proposed clinical applications. The envi- sioned embodiment and use of the system are instrumented shoes individually calibrated to assess in combination with real time video from videoconferencing codecs weight bearing capabilities in the context of telerehabilitation care. Work on the integration of the system with a clinical system for telere- habilitation is on-going. Manuscript received May 10th 2007. This work was supported by the Cana- dian Institute for Health Research, Institute of Musculoskeletal Health and Arthritis (IMHA) under the Invention-Tools, Techniques and Devices for Research and Medicine program. Grant #200307ITM-120560. A Authier Eng jr is with Electrical Engineering and Computing Depart- ment, Université de Sherbrooke and Research Centre on Aging Sherbrooke, Canada (ariane.authier@usherbrooke.ca), P. Boissy PhD is with the Kinesiology Department, Université de Sher- brooke, and Research Centre on Aging, Sherbrooke, Canada (819-821-1170, patrick.boissy@usherbrooke.ca). J. Beauvais Eng, PhD is with the Electrical Engineering and Computing Department, Université de Sherbrooke (jacques.beauvais@usherbrooke.ca). R Fontaine Eng, PhD is with the Electrical Engineering and Computing Department, Université de Sherbrooke and Research Centre on Aging, Sher- brooke, Canada (rejean.fontaine@usherbrooke.ca).