The influence of interelectrode distance on bipolar recording of sensory nerve action potential. A mathematical study.

Bipolar recording of Extracellular Single Fiber Action Potential (ESFAP) and Sensory Nerve Action Potential (SNAP) were simulated mathematically. The study attempts to analyze the influence of interelectrode distance on the amplitude of bipolar recordings. Simulations of bipolar recordings of ESFAP and SNAP presented four major peaks whose relations changed with the distances between the electrodes which compose the derivation. The maximum amplitude of bipolar ESFAP was produced at similar interelectrode distances for the range of fibers studied in clinical practice. In bipolar recordings of SNAP, the interelectrode distance producing the maximum amplitude increases with the distance between the place of stimulation and the place of recording.