Novel thin film cuff electrode for neural stimulation

One approach to reestablish disabled functions or to treat chronic diseases of patients is the electrical stimulation of nerves. This requires, in addition to special stimulator electronics, a dedicated electrode in close contact with the specific nerve. We present a new type of spiral self-sizing nerve cuff electrode capable of selective activating specific regions of a nerve trunk. The cuff consists of eight active contacts produced by technologies taken from microelectronics. A platinum metallization for contacts and connection wires was made on a sandwich flexible bi-layer polyimide foil substrate embedded in a biocompatible insulation (silicone). With such a design wrap thickness under 40μm were obtained. The spiral-like arrangement of the cuff placed around the nerve trunk allows a tight cuff to nerve contact without penetrating the nerve. The miniaturized active contact area along with the increased number of electrodes imply a highly spatial selectivity together with the need for a high charge transfer. Therefore we are focusing our research on alternative coatings like iridium oxide which promises to enable high current densities. The electrode´s design, requirements and production are described.