Automating arm movement training following severe stroke: functional exercises with quantitative feedback in a gravity-reduced environment

IEEE Trans Neural Syst Rehabil Eng. 2006 Sep;14(3):378-89. doi: 10.1109/TNSRE.2006.881553.


An important goal in rehabilitation engineering is to develop technology that allows individuals with severe motor impairment to practice arm movement without continuous supervision from a rehabilitation therapist. This paper describes the development of such a system, called Therapy WREX or ("T-WREX"). The system consists of an orthosis that assists in arm movement across a large workspace, a grip sensor that detects hand grip pressure, and software that simulates functional activities. The arm orthosis is an instrumented, adult-sized version of the Wilmington Robotic Exoskeleton (WREX), which is a five degrees-of-freedom mechanism that passively counterbalances the weight of the arm using elastic bands. After providing a detailed design description of T-WREX, this paper describes two pilot studies of the system's capabilities. The first study demonstrated that individuals with chronic stroke whose arm function is compromised in a normal gravity environment can perform reaching and drawing movements while using T-WREX. The second study demonstrated that exercising the affected arm of five people with chronic stroke with T-WREX over an eight week period improved unassisted movement ability (mean change in Fugl-Meyer score was 5 points +/- 2 SD; mean change in range of motion of reaching was 10%, p < 0.001). These results demonstrate the feasibility of automating upper-extremity rehabilitation therapy for people with severe stroke using passive gravity assistance, a grip sensor, and simple virtual reality software.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Aged
  • Arm / physiopathology
  • Biofeedback, Psychology / methods*
  • Exercise Therapy / instrumentation*
  • Exercise Therapy / methods
  • Female
  • Humans
  • Male
  • Middle Aged
  • Motion Therapy, Continuous Passive / instrumentation*
  • Motion Therapy, Continuous Passive / methods
  • Paresis / etiology
  • Paresis / physiopathology
  • Paresis / rehabilitation*
  • Physical Stimulation / instrumentation
  • Physical Stimulation / methods
  • Robotics / instrumentation*
  • Robotics / methods
  • Stroke / complications
  • Stroke / physiopathology
  • Stroke Rehabilitation*
  • Telemedicine / instrumentation*
  • Telemedicine / methods
  • Therapy, Computer-Assisted / instrumentation
  • Therapy, Computer-Assisted / methods
  • User-Computer Interface
  • Weightlessness Simulation