A new clinical study by the Veterans Health Administration will involve about 200 patients who have had brain injuries or strokes that impair the ability to move their limbs. While conventional physical therapy can assist patients in compensating for the damage, many patients plateau in their recoveries after a few weeks. However, some patients have been able to continue progressing due to an experimental robot that has been used for arm rehabilitation since the early 1990s. The machine and three other similar ones, are being used in large-scale testing that is comparable to late-stage drug trials. These are the first such trials for therapeutic robots. Randomized trials will begin in 2006 and will continue for three years in multiple hospitals to test the robots and compare them with conventional therapy. If results of testing appear to improve recovery, the clinical study could provide the evidence required to allow adoption of the clinical use of the robot throughout the VA system and further, says Albert Lo, a Yale University neurologist and principal investigator in the trials. The robots were built by two Massachusetts Institute of Technology (MIT) engineers, Neville Hogan and Hermano Igo Krebs, who also founded Interactive Motion Technologies to commercialize the invention. Physical therapy treatments move a patient's limbs repeatedly in a pattern, but the arm robot uses the patient as a participant and only provides help when needed. The software in the robot adjusts to the progress of the patient, and the device has a video game component that directs therapy and helps maintain patient motivation.