Selective fascicular recording of the hypoglossal nerve using a multi-contact nerve cuff electrode

The use of nerve cuff electrodes as part of a closed loop functional electrical stimulation (FES) system has been demonstrated as a reliable alternative to artificial sensors (e.g., strain gauge). To circumvent the need for multiple electrodes to record neural activity from 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 and computational methods. This involved analyzing recorded action potentials from 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 at the fascicle level. The computed overall selectivity of the FINE was SI_FINE = 44.5 ± 11.2 and SI_FINE = 52.2 for the experimental (n = 7) and computational (n = 1) data, respectively. The results of this study indicate the feasibility of using the FINE as a means of selectively recording neural signals from a multifasciculated nerve.