A system for the delivery of programmable, adaptive stimulation intensity envelopes for drop foot correction applications

• Published in: Medical engineering & physics 2006-03, Vol.28 (2), p.177-186
• Main Authors: Breen, P.P., O’Keeffe, D.T., Conway, R., Lyons, G.M.
• Format: Article
• Language: English
• Subjects: Computer Graphics; Drop foot stimulator; Electric Stimulation Therapy - instrumentation; Electric Stimulation Therapy - methods; Equipment Design; Equipment Failure Analysis; Functional electrical stimulation (FES); Gait Disorders, Neurologic - rehabilitation; Humans; Signal Processing, Computer-Assisted - instrumentation; Stimulation intensity envelope; Therapy, Computer-Assisted - instrumentation; Therapy, Computer-Assisted - methods; User-Computer Interface
• ISSN: 1350-4533; 1873-4030
• DOI: 10.1016/j.medengphy.2005.04.008

We describe the design of an intelligent drop foot stimulator unit for use in conjunction with a commercial neuromuscular electrical nerve stimulation (NMES) unit, the NT2000. The developed micro-controller unit interfaces to a personal computer (PC) and a graphical user interface (GUI) allows the clinician to graphically specify the shape of the stimulation intensity envelope required for a subject undergoing drop foot correction. The developed unit is based on the ADuC812S micro-controller evaluation board from Analog Devices and uses two force sensitive resistor (FSR) based foot-switches to control application of stimulus. The unit has the ability to display to the clinician how the stimulus intensity envelope is being delivered during walking using a data capture capability. The developed system has a built-in algorithm to dynamically adjust the delivery of stimulus to reflect changes both within the gait cycle and from cycle to cycle. Thus, adaptive control of stimulus intensity is achieved.