Signal strength versus cuff length in nerve cuff electrode recordings

Abstract

When a nerve cuff electrode is used for the recording of signals from peripheral nerves, cuff dimensions have to be chosen. Traditionally, the peak-to-peak amplitude of the single-fiber action potential (SFAP) is optimized through the choice of cuff diameter and cuff length. In this paper, the dependency of the root-mean-square (RMS) value of the nerve signal on the cuff dimensions was studied and compared with the peak-to-peak value of the SFAP. A simple approximation for signal optimization by cuff dimensioning is suggested. The results were obtained from modeled SFAPs and from the electroneurogram (ENG) created by superimposed SFAPs, obtained from an inhomogeneous volume conductor model. The results show that the RMS value of the nerve signal is considerably more sensitive to the cuff length than the SFAP peak-to-peak amplitude, and that the RMS of the ENG is a linear function of the fiber diameter.

Self-Closed Parylene Cuff Electrode for Peripheral Nerve Recording

“…Except for the blue color marked channels (channel 2, 11 and 16), a clear CAP can be found in every channel. These signals looked like as expected, the amplitudes of the signals are also comparable with the literature reported by Donaldson [29], [71] and Struijk [19], [45], [72], [73] which are hundreds of microvolts. Due to signal shunting by lower resistivity saline, a cuff that is too large and fits too loosely will produce smaller signals.…”

“…The limits of bonding methods of the electrodes and the external systems are another reason for the failure of multichannel. In many recording situations, the length of the cuff should be as long as possible unless the space is restricted due to anatomical properties [45]. Even a small increasing of length would increase the root mean square (RMS) value of the neural signals [46].…”

Model-based evaluation of the short-circuited tripolar cuff configuration

“…The change of the SFAP amplitude is much smaller than the change of the CAP, which could be explained by the tendency of the RMS of a more compound nerve signal to be more sensitive to cuff length than the amplitude of a SFAP [3].…”

“…This configuration has been widely used because of its ability to reduce interfering signals. Lately, more effort has been put into optimization of the recordings, both by studying the effect of cuff dimensions on the nerve signal [3,5,17,20,22] and by creating new configurations and cuffs designs that further reduce the interference pick-up [1, 2, 4, 14-16, 22, 23]. Some new configurations involve multiple amplifiers [14,16], such as in the true tripolar or screened tripolar configurations, where two amplifiers are used, resulting in recordings with twice the nerve signal amplitude as compared with the traditional tripolar configuration having just one amplifier.…”

Progress of Flexible Electronics in Neural Interfacing – A Self‐Adaptive Non‐Invasive Neural Ribbon Electrode for Small Nerves Recording

“…J. Struijk and L. Andreasen showed that an optimized confi guration and closure of the cuff electrode contributes to the neural signal acquisition. [ 34,35 ] T. Stieglitz et al developed processing technology for fl exible, light-weight, micromachined, multichannel cuff electrodes. [ 36 ] With this device, X. Navarro et al were able to selectively stimulate the fascicular of a rat's sciatic nerve.…”