Characterization of Electrodes for Kilohertz Electrical Stimulation

Abstract

Kilohertz electrical stimulation (KES) induces repeatable and reversible conduction block of nerve activity and is a potential therapeutic option for various diseases and disorders resulting from pathological or undesired neurological activity. However successful translation of KES nerve block to clinical applications is stymied by many unknowns such as the relevance of the onset response, acceptable levels of waveform contamination, and optimal electrode characteristics. We investigated the role of electrode geometric surface area and electrode contact material on the KES nerve block threshold using 20 and 40 kHz current-controlled sinusoidal KES. Electrodes were electrochemically characterized and used to characterize typical KES waveforms and electrode charge characteristics. KES nerve block amplitudes, onset duration, and recovery of normal conduction after delivery of KES were evaluated for effective KES nerve block. Results from this investigation demonstrate that increasing electrode geometric surface area provides for a more efficient KES nerve block and different materials has no effect on KES nerve block thresholds. Reductions in block threshold by increased electrode surface area were found to be KES frequency dependent, with block thresholds reduced by >2x with 20 kHz KES waveforms and >3x for 40 kHz KES waveforms.