Résumé
Cuff electrodes have several advantages for in situ recording of ENG signal. They are easy to implant and not very invasive for the patient. Nevertheless, they are subject to parasitic background noise, especially the EMG generated by the muscles. We show that the use of large numbers of poles can increase the sensitivity of cuff electrodes as well as their selectivity with respect to a efficient noise rejection. We investigate several configurations and compare the performances of a tripolar cuff electrode versus a multipolar one in numerical simulation. One the other hand the use of cuff electrodes leads to the recording of the sum of the signals generated by all the axons within the nerve. This puts in evidence the need of signal separation techniques that require a large amount of information. Again, we show that multipolar electrodes can solve this problem since poles can be switched one to another, provided that they are distributed along a regular tessellation. Finally, we present the structure of an ASIC preamplifier aimed to obtain the Laplacian of the potential by spatial filtering and rejecting low-frequency noise.