Logo for the Journal of Rehab R and D

Volume 46 Number 2, 2009
   Pages 243 — 256

Abstract - Wireless wearable controller for upper-limb neuroprosthesis

Christa A. Wheeler, MS;1* P. Hunter Peckham, PhD1-3

1Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH; 2Center of Excellence in Functional Electrical Stimulation, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH; 3Department of Orthopaedics, MetroHealth Medical Center, Cleveland, OH

Abstract — The objective of this project was to develop a wireless, wearable joint angle transducer to enable proportional control of an upper-limb neuroprosthesis by wrist position. Implanted neuroprostheses use functional electrical stimulation to provide hand grasp to individuals with tetraplegia. Wrist position is advantageous for control because it augments the tenodesis grasp and can be implemented bilaterally. Recently developed, fully implantable multichannel stimulators are battery-powered and use wireless telemetry to control stimulator outputs. An external wrist controller was designed for command signal acquisition for people with cervical-level spinal cord injury to control this implantable stimulator. The wearable controller, which uses gigantic magnetoresistive sensing techniques to measure wrist position, is worn on the forearm. A small dime-sized magnet is fixed to the back of the hand. Results indicate that the device is a feasible control method for an upper-limb neuroprosthesis and could be reduced to a small "wristwatch" size for cosmesis and easy donning.

Key words: control, functional electrical stimulation, gigantic magnetoresistance, hand grasp, joint angle sensor, neuroprosthesis, rehabilitation, spinal cord injury, tetraplegia, wireless, wrist angle.

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