Development of a fully implantable EMG measurement system: Status report on the MyoPlant project

MyoPlant is a publicly funded research project that developed a fully implantable EMG measurement system. The system consists of a central implant, and single silicone electrodes that are placed on the muscles of choice. Electrodes are connected by means of subcutaneous cables. While electrodes were tested in rats, the complete system was tested in sheep and rhesus macaques. Electrodes showed good handling during surgery and were well tolerated by all animals without adverse reactions. No electrode defects were observed during the runtime of the project. Data from the animal trials showed that electrodes are well encapsulated after approximately eight weeks. The custom designed chip in the central implant performed as intended. Data transmission and inductive energy supply worked as designed. The latter was susceptible to coil misalignment. Electromyographic signals recorded with the system showed very good separation between electrodes, no cross-talk and no 50Hz noise. Amplitudes were consistent between sessions. Overall, we were able to demonstrate the technical feasibility of a fully implantable EMG measurement system. The recorded signals seem well suited to control modern myoelectric arm prostheses with multiple degrees of freedom in the future.