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Application of tilt sensors in functional electrical stimulation
R Dai1, R B Stein, B J Andrews
1Division of Neuroscience, University of Alberta, Edmonton, Canada.
IEEE Transactions on Rehabilitation Engineering : a Publication of the IEEE Engineering in Medicine and Biology Society
|June 1, 1996
Summary
This study shows that miniature tilt sensors can effectively control Functional Electrical Stimulation (FES) to improve gait for stroke and spinal cord injury (SCI) patients. The device offers improved cosmesis and ease of use, aiding in foot drop correction.
Area of Science:
- Biomedical Engineering
- Rehabilitation Technology
- Neuroscience
Background:
- Functional Electrical Stimulation (FES) is used to improve gait in individuals with stroke or incomplete spinal cord injury (SCI).
- Traditional FES control methods often rely on external sensors or foot switches, which can be cumbersome or less effective.
- Tilt sensors (inclinometers) offer a potential solution for more integrated and responsive FES control.
Purpose of the Study:
- To investigate the efficacy of tilt sensors for controlling FES to enhance gait in stroke and SCI populations.
- To develop and evaluate a miniature, integrated footdrop stimulator utilizing a magnetoresistive tilt sensor.
- To assess the device's performance in detecting step intention and controlling FES for improved foot clearance and gait.
Main Methods:
- Utilized low-pass filtering (1.5-2 Hz) to minimize acceleration artifacts from tilt sensor data.
- Employed a finite state approach for the tilt sensor fixed on the shank to detect step intention.
- Designed and integrated a magnetoresistive tilt sensor into a miniature footdrop stimulator, eliminating external cables.
- Adjusted stimulation parameters (thresholds, duration, intervals) for personalized FES control.
Main Results:
- Identified distinct lower leg signal patterns with tilt sensors in control and footdrop subjects during level walking.
- Demonstrated effective detection of step intention and FES control using the tilt sensor-based finite state approach.
- Initial trials showed substantial gait improvements in some stroke and SCI subjects.
- Subjects reported positive feedback on the device's cosmesis and ease of use.
Conclusions:
- Miniature tilt sensors integrated into FES devices are effective for improving gait in individuals with stroke and SCI.
- The developed footdrop stimulator offers advantages over traditional devices in terms of integration, cosmesis, and user-friendliness.
- Tilt sensor-based FES control represents a promising advancement in neurorehabilitation technology for gait assistance.