On the importance of configuration and closure of nerve cuff electrodes for recording

The extraction of neural information for feedback in functional electrical stimulation is limited by the poor signal to noise ratio (SNR) in the nerve recordings. Cuff electrodes have been successful in improving the SNR, but many parameters such as cuff dimensions, configurations and closing methods affect the obtainable SNR. In the present work we studied the effect of the monopolar and tripolar configuration on signal and noise in cuff recordings. Further, we compared two different cuff closures, the slit closure and the closure using interdigitating tubes. The cuff recordings were performed with an artificial nerve fiber set-up, and the results showed that the tripolar configuration gave a 2.4 times higher SNR than the monopolar configuration. A slit closure with a flap resulted in a 6% reduction of the nerve signal amplitude whereas the closure using interdigitating tubes reduced the signal with 19%.