Abstract: An input command controller (A) provides logic function selection signals and proportional signals. The signals are generated by movement of a ball member (12) and socket member (14) relative to two orthogonal axes. When the joystick is implanted, a transmitter (50) transmits the signals to a patient carried unit (B). The patient carried unit includes an amplitude modulation algorithm such as a look-up table (124), a pulse width modulation algorithm (132), and an interpulse interval modulation algorithm (128). The algorithms derive corresponding stimulus pulse train parameters from the proportional signal which parameters are transmitted to an implanted unit (D). The implanted unit has a power supply (302) that is powered by the carrier frequency of the transmitted signal and stimulation pulse train parameter decoders (314, 316, 318). An output unit (320) assembles pulse trains with the decoded parameters for application to implanted electrodes (E).

Abstract: A helix (10) is defined by two lengths of multistrand wire (14) each surrounded by flexible, biocompatible insulation (18). A silicon elastic sheath (30) surrounds the helix and extends to a terminal end of the electrode. At the terminal end, a portion of the wire is wrapped around a periphery of the sheath to define a tissue contacting surface (34). A shaft (42) of a polypropylene anchor (40) is inserted into a hollow core (20) of the helix and thermally deformed into mechanical engagement with the helix. The anchor has a plurality of polypropylene tines or barbs (44) which firmly engage the tissue within which it is inserted but which yield for electrode removal without ripping the tissue.