Arthur Prochazka's Lab

ReJoyce Upper-extremity Workstation

About 5 million people in North America (0.5M in Canada) live with the after-effects of stroke. About 3M of these people (300,000 in Canada) have partly paralyzed (paretic) arms and hands. As a result, they have great difficulty performing manual tasks of daily life. In conventional therapy, patients perform simple motor tasks over and over again. This quickly becomes boring. Compliance drops off and functional improvements are less than ideal.

To fill this important gap, Drs. Jan Kowalczewski and Arthur Prochazka invented the ReJoyce (Rehabilitation Joystick for Computer Exercise), a novel spring-loaded arm holding attachments that simulate activities of daily life (ADLs). The device provides enjoyable exercises in the guise of computer games. Tasks involving range of motion as well as fine manipulation are included. Simple games, like driving, catching, pick-and-place and target-shooting, motivate patients to perform ADLs again and again, gradually increasing the difficulty levels (“shaping”). Sensors in the device measure movements and forces, allowing therapists and researchers to evaluate outcomes objectively (see below).

The ReJoyce is portable and affordable enough for in-home use in conjunction with Internet-based In-Home Tele-rehabilitation (IHT) system (see

So far all hand function tests have been administered and scored by therapists, introducing subjective value-judgements. The ReJoyce Automated Hand Function Test (RAHFT) is the first fully automated and quantitative test of upper extremity function, providing objective, standardized outcome measures, with scores for each task as well as an overall score.

Randomized controlled studies have shown that functional electrical stimulation (FES) of the paretic muscles in conjunction with daily hand exercises over several weeks can significantly improve hand function. ReJoyce can be used in combination with FES devices, like the Bioness H200 or a Rehabtronics Hand stimulator wristlet now under development.

In pilot studies, FES-assisted exercise sessions were supervised over the Internet for 1 hour/day by remote therapists using an Internet video-conferencing system. The supervisors controlled the users' computers remotely and provided encouragement and advice as well as choosing games and adjusting their difficulty according to the users' abilities. For FES assistance with hand opening we used a modified Impact Cuff (Prochazka et al., 1997, Arch Phys Med Rehabil, 78, 608-14), a FES-device comprising a garment with in-built electrodes. Two pilot studies on chronic and sub-acute stroke subjects (Gritsenko and Prochazka 2004; Kowalczewski et al. 2007: get pdfs below) were performed at the Glenrose Rehabilitation Hospital from 2002 to 2006. The overall conclusion was that daily FES-assisted exercise of the hemiplegic hand for three weeks results in clinically significant improvements in FES-assisted hand function. ReJoyce, and ReJoyce-based in-home therapy, will soon be commercially available at for clinics, and for people who have suffered a stroke, spinal cord, or other neurological injury resulting in loss of hand function.

Related Files:


Gritsenko V, and Prochazka A. A functional electric stimulation-assisted exercise therapy system for hemiplegic hand function. Archives of Physical Medicine and Rehabilitation 85: 881-885, 2004.


Kowalczewski J, Gritsenko V, Ashworth N, Ellaway P, and Prochazka A. Upper-extremity functional electric stimulation-assisted exercises on a workstation in the subacute phase of stroke recovery. Arch Phys Med Rehabil 88: 833-839, 2007.


None available at the moment