A programmable wireless oscillating field stimulator
While nerve cells in the brain were not previously thought to regenerate, previous studies have shown neuron regeneration after lesions in several regions of the cerebral cortex. In separate research, the application of dc voltage gradients within tissues of the spinal central nervous system has been shown to promote tissue development and repair. It has been hypothesized that miniaturized stimulator devices can promote neuronal regeneration after damaged caused as a result of Spinal Cord Injury (SCI). To comprehend the capability for electrically stimulated central nervous system repair, we developed a wirelessly programmable oscillating field stimulator. Our system monitors the electric field at the injury site and stimulates with various waveforms. The device printed circuit board (PCB) was designed to match the size of a circular, 25mm in diameter, battery. The PCB fabrication included the use of automatic pick-and-place machines, used to place the components with high speed and high precision. Currently wireless data transfer reliably up to distances of approximately 6 feet. To validate the system efficiency and biocompatibility we developed and performed in-vivo studies, stimulation was evaluated based on its quantified delivered amplitude in a rat model. Different stimulus where applied varying from 300uV/mm to 1200uV/mm. Therefore, we have proposed to examine various stimulus strengths and a range of frequencies to observe how the desired field strength is generated in the rat’s spinal cord. Also, improved outcomes through a closed-loop system with bio-impedance feedback were tested. It is expected that the application of a controlled optimal stimulus will lead to gradual improvement in repairing damaged spinal cord tissue.^
Pedro P. Irazoqui, Purdue University.