S-2-09-05
AMBULATION AFTER SPINAL INJURY: New possibilities for FES
Brian J. Andrews Ph.D. (Dept. Biomedical Engineering Univ. of Alberta & Glenrose Hospital, Edmonton, Canada)
In this paper new possibilities are described for the control of FES ambulation systems. These involve the application of artificial intelligence and neuro-fuzzy computing techniques. Improved control techniques have also been augmented by parallel development of new sensing technology involving the use of cuff electrodes to sense signals from natural sense organs and the application of micro-machined sensors such as accelerometers and rate gyroscopes.
For some, FES can be usefully combined with advanced bracing techniques in so called "Hybrid Systems". These offer improved ambulatory performance by reducing FES induced muscle fatigue, enhanced joint motion control, reduced physical effort and increased stability.
The presentation will be illustrated by describing a recently developed hybrid system comprising a Cochlear-22 channel implanted electrode FES system and a new two-part brace system.
S-2-09-06
A NEW SYSTEM TO ASSIST WALKING WITH FUNCTIONAL ELECTRICAL STIMULATION
R.B. Stein, M. Wieler and W.G.R Gibson (University of Alberta and NeuroMotion Inc., Edmonton, Canada)
Functional electrical stimulation (FES) was first introduced to assist in the gait of persons with footdrop over 35 years ago, but has not found widespread clinical application. The most common device remains an ankle-foot orthosis, although the common plastic brace has several deficiencies. Recently, a multi-centre trial has been conducted across Canada (Montreal, Toronto, Edmonton, Vancouver) using simple, surface FES devices (1-4 channels of stimulation). Over 40 persons participated who had a spinal cord injury or stroke, but could only walk at slow speed (<0.8 m/s). The results showed an average early increase of 20% in walking speed and a further 20% increase over the next 6 months or more. A questionnaire indicated that walking was easier with FES and acceptance of the devices was very good. Suggestions from the trial have been incorporated into a new device (WalkAide) that will be demonstrated at the meeting and will shortly be available commercially. WalkAide is self-contained with electrodes, a sensor and a microprocessor-controlled, single channel stimulator in a cuff that fits on the leg reproducibly from day to day. A person with only one functional hand can easily put the device on and no external wires are normally needed to hand or foot switches. An inbuilt tilt sensor measures the orientation of the leg with respect to gravity and the microprocessor automatically uses the sensory information to turn stimulation on and off. A hand-held clinician system allows the parameters of stimulation to be optimized for each person. The batteries can be recharged without removal, simply by placing the whole device in a specially designed charger.
Multi-centre trials supported by the Medical Research Council and the Neuro Science Network of Canada.
