Automatic identification of gait events using an instrumented sock

In addition of the potential of using textile-based transducers in future devices, I also think in a possible help to assess gait objectively (to help improve the measurement of the ICARS scale)

Journal of NeuroEngineering and Rehabilitation 2011, 8:32 doi:10.1186/1743-0003-8-32
Published: 27 May 2011, OPEN ACCESS

Stephen J Preece, Laurence P J Kenney, Matthew J Major, Tilak Dias, Edward Lay and Bosco T Fernandes

Background
Textile-based transducers are an emerging technology in which piezo-resistive properties of materials are used to measure an applied strain. By incorporating these sensors into a sock, this technology offers the potential to detect critical events during the stance phase of the gait cycle. This could prove useful in several applications, such as functional electrical stimulation (FES) systems to assist gait.
Methods
We investigated the output of a knitted resistive strain sensor during walking and sought to determine the degree of similarity between the sensor output and the ankle angle in the sagittal plane. In addition, we investigated whether it would be possible to predict three key gait events, heel strike, heel lift and toe off, with a relatively straight-forward algorithm. This worked by predicting gait events to occur at fixed time offsets from specific peaks in the sensor signal.
Results
Our results showed that, for all subjects, the sensor output exhibited the same general characteristics as the ankle joint angle. However, there were large between-subjects differences in the degree of similarity between the two curves. Despite this variability, it was possible to accurately predict gait events using a simple algorithm. This algorithm displayed high levels of trial-to-trial repeatability.
Conclusions
This study demonstrates the potential of using textile-based transducers in future devices that provide active gait assistance.

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