Developing and Evaluating a Flexible Wireless Microcoil Array Based Integrated Interface for Epidural Cortical Stimulation.

Stroke leads to serious long-term disability. Electrical epidural cortical stimulation has made significant improvements in stroke rehabilitation therapy. We developed a preliminary wireless implantable passive interface, which consists of a stimulating surface electrode, receiving coil, and single flexible passive demodulated circuit printed by flexible printed circuit (FPC) technique and output pulse voltage stimulus by inductively coupling an external circuit. The wireless implantable board was implanted in cats\u27 unilateral epidural space for electrical stimulation of the primary visual cortex (V1) while the evoked responses were recorded on the contralateral V1 using a needle electrode. The wireless implantable board output stable monophasic voltage stimuli. The amplitude of the monophasic voltage output could be adjusted by controlling the voltage of the transmitter circuit within a range of 5-20 V. In acute experiment, cortico-cortical evoked potential (CCEP) response was recorded on the contralateral V1. The amplitude of N2 in CCEP was modulated by adjusting the stimulation intensity of the wireless interface. These results demonstrated that a wireless interface based on a microcoil array can offer a valuable tool for researchers to explore electrical stimulation in research and the dura mater-electrode interface can effectively transmit electrical stimulation

An Implantable High-Voltage Cortical Stimulator for Post-stroke Rehabilitation Enhancement with High-Current Driving Capacity

This paper presents a high-voltage, high-current implantable cortical stimulation integrated circuit aiming at supporting rehabilitation of patients suffering from stroke. In this context, a large area of the motor cortex needs to be stimulated, requiring high current densities at the electrode-electrolyte interface. The designed integrated circuit contains eight fully programmable stimulation channels generating biphasic constant current pulses up to 8mA from a 20V supply. The current mismatch between positive and negative pulses has been evaluated at 0.03 per cent. The chip has been fabricated in a AMS 0.18m high voltage CMOS process, and has a die area of 5mm2