An electrode arrangement is described for sensing electrical activity in target tissue. An inner electrode has an elongate electrode body formed as a cylindrical section with an inner penetrating end for insertion into the stapedius muscle target tissue. An outer electrode fits over the inner electrode and an outer penetrating end for insertion into the target tissue. The two electrodes are joined together with their electrode bodies in parallel so that the penetrating ends of the electrodes penetrate in the same direction into the target tissue to sense electrical activity in the target tissue.