Evaluation of a wireless in-shoe sensor based on ZigBee used for drop foot stimulation
Journal: RWW 2012 - Proceedings: IEEE Radio and Wireless Symposium, RWS 2012
External stimulation of the Tibialis anterior muscle is a technique employed to improve mobility for patients with some neurological disabilities causing drop foot. This is achieved by electrically stimulating the motor nerve which causes contraction of the muscle. For functional use the stimulation is applied during periods when the foot needs to be lifted. This period is detected using a sensor usually placed in the shoe of the patient. The stimulation unit is placed distal from the sensor which requires a robust link to ensure a safe and reliable function. A wireless link is a convenient choice especially for users with limited mobility. However, a wireless link is subject to interference that could cause reliability issues and affect latency of transmissions. This paper investigates a wireless link based on ZigBee and estimates the reliability and latency in laboratory conditions with different interference sources. Results are encouraging and showed acceptable performances for such an application. Clinical trials of this system are being undertaken at present. © 2012 IEEE.
Evaluation of a wireless in-shoe sensor based on ZigBee used for Drop Foot Stimulation
Journal: IEEE Radio & Wireless WeekAbstract:
Each year, hundreds of thousands of people are affected by a neurological related disease or lesion causing partial or complete dysfunction of one or more limbs. Functional Electrical Stimulation (FES) techniques have resulted in significant improvement in mobility and function for many of these patients. FES relies on one or more sensors to trigger stimulation. These sensors usually have to be placed distal from the stimulation unit and this has necessitated the use of a robust wired link. However, wires are often rejected by patients due to physical impracticality and cosmesis. The obvious solution is to replace the wired system with a wireless network. However, as a consequence of the safety implications inherent in this application, any wireless network of this type should approach the reliability of the existing wired system and also achieve acceptable transmission latencies. This paper investigates the feasibility of a wireless FES system composed of a sensor node placed in the shoe connected by wireless link to a stimulation node. The experimental results of reliability and transmission latency experiments performed on the system in both laboratory and under real-world conditions show acceptable and repeatable performance with and without sources of interference.
Evaluation of a wireless in-shoe sensor based on ZigBee used for drop foot stimulation.