The first generation system received FDA marketing approval in 1997. The IJAT uses Hall-effect magnetic field sensors and a magnet to sense wrist angle. The magnet is inserted into the lunate and the sensors are inserted into the radius near the articular surface of the bone. Sensor outputs are relayed to the stimulator-telemeter device and transmitted out of the body through a radio frequency link using reflectance modulation. Elbow and forearm movement is controlled by voluntary activation of the antagonists.
Participants undergo at least one month of surface stimulation prior to surgery.
Implantation surgery is followed by three weeks of casting, and then a period of muscle conditioning using the implant stimulator. A two to three week rehabilitation training and evaluation period is used to complete the initial set up of the grasp and control parameters, train the individual in the use of the neuroprosthesis, and evaluate the function provided. The project is sponsored by MetroHealth Medical Center, Department of Veterans Affairs Rehabilitation Research and Development Service and National Institutes of Health Neural Prosthesis Program.