Recording intramuscular EMG signals using surface electrodes

The control of multifunctional myoelectric prostheses is a substantive area of research with the potential to dramatically improve the independence of transradial amputees. We present preliminary data for the development of a new technique for obtaining multiple electromyographic (EMG) signals for controlling multifunctional myoelectric hand and wrist prostheses. A completely embedded passive conductor is proposed to transmit intramuscular EMG signals to a distant location just beneath the skin surface with a subcutaneous terminal. These signals can then be recorded with conventional surface electrodes. The surface recorded intramuscular EMG (SRI EMG) signals would closely follow the electrical potential at the muscle fiber source. They would be extremely selective, and the well-known effect of spatial filtering, which reduces the amplitude and frequency content of surface EMG signals, would be virtually eliminated. It would, therefore, be possible to access control signals from deep or small muscles that would otherwise be unavailable. Based on this technique, a new generation of multifunction myoelectric prostheses can be developed. The technique is a simple, inexpensive, and robust alternative to implanted telemetry systems and percutaneous electrodes.