Selective Fascicular Recording of the Hypoglossal Nerve Using a Multi- Contact Nerve Cuff Electrode

The use of nerve cuff electrodes as p a r t of a closed loop functional electrical stimulation (FES) system has been demonstrated as a reliable alternative to artificial sensors (e.g., strain gauge). T o circumvent the need for multiple electrodes to record neural activity f rom different fascicles within a nerve, the flat interface nerve electrode (FINE) is presented as a potential approach to discern spatially disparate sources using a single implantable device. The recording selectivity of the FINE was investigated using both experimental a n d computational methods. This involved analyzing recorded action potentials f rom six acute beagle experiments and a finite element model, which was constructed from a nerve image obtained from one experiment. The performance of the electrode was assessed by a selectivity index that quantified the recording selectivity a t the fascicle level. T h e computed overall selectivity of the FINE was SI-FINE = 44.5 f 11.2 and SI-FINE = 52.2 for the experimental (n=7) and computational (n=l) data, respectively. The results of this s tudy indicate the feasibility of using the FINE as a means of selectively recording neural signals f rom a multifasciculated nerve. Keywords-selectivity index, flat interface nerve electrode, hypoglossal nerve, action potential; neural recording