repetitive strain injury

Generic term for various kinds of work-related musculoskeletal injuries, such as carpal tunnel syndrome and tendonitis. Symptoms of RSI include inflammation of tendon sheaths, mainly in the hands and wrists, which may be disabling. It is found predominantly in factory workers involved in constant repetitive movements, and in those who work with computer keyboards. The symptoms include aching muscles, weak wrists, tingling fingers, and in severe cases, pain and paralysis. Some victims have successfully sued their employers for damages.

In many RSI cases, there is no actual sign of tissue damage and some researchers are beginning to believe that the origin of the pain may be due to a problem in the brain rather than the tissues, with the brain rewiring its neurones to cope with continual repetitive movements until it loses awareness of which finger is which.

Focal hand dystonia, commonly known as writer's or musician's cramp, one of the most disabling forms of RSI, is characterized by spasms of the fingers and wrist causing uncontrollable hand movements. It has proved notoriously difficult to treat but responds well to a form of sensory retraining therapy (pioneered by US physical therapist Nancy Byl), where patients slowly relearn sensory distinctions by performing structured delicate tasks while blindfolded.