Increased selectivity of clinical peripheral nerve interfaces

Selective, spiral peripheral nerve interfaces have been implemented in several clinical applications. Modeling results and intraoperative validation studies of the Flat Interface Nerve Electrode (FINE) demonstrate that with single channel, monopolar stimulation the FINE can increase the selectivity of neural stimulation. We hypothesize the stimulation selectivity can be further improved and potentially equal to intrafascicular stimulation by more sophisticated stimulation fields and interfascicular placement of electrodes with directed stimulation surfaces. We have developed an accurate linear approximation to the double cable model that is fast enough to implement non-gradient descent optimization techniques. Simulations suggest that anodal surround field shaping and directed interfascicular stimulation can increase the stimulation selectivity without placing electrodes inside the fascicles.