Development of a self-contained accelerometry based system for control of functional electrical stimulation in hemiplegia

For stroke patients, functional electrical stimulation (FES) has been shown in the past to greatly reduce gait impairments. A critical element of the success of this intervention is accurate and reliable triggering of the stimulation for step initiation. Foot switches are the most commonly used devices for triggering hemiplegic FES gait, but they have been known to produce unreliable results and degrade over time. This paper outlines the development of a self-contained accelerometry-based gait stimulation system that can be worn around the waist and unlike other systems, adds no additional hardware or equipment to don or doff. An acceleration algorithm was developed and shown to have significantly shorter heel strike detection delays than when detecting with a heel sensor which could lead to improved stimulation timing for step initiation.