Journal of Pain Research (Jun 2021)
Gate Mechanism and Parameter Analysis of Anodal-First Waveforms for Improving Selectivity of C-Fiber Nerves
Abstract
Siyu He,1 Kornkanok Tripanpitak,2 Yu Yoshida,2 Shozo Takamatsu,3 Shao Ying Huang,4 Wenwei Yu2,5 1Graduate School of Engineering, Chiba University, Chiba, Japan; 2Graduate School of Science and Engineering, Chiba University, Chiba, Japan; 3Omron Healthcare Co., Ltd, Kyoto, Japan; 4Engineering Product Development, Singapore University of Technology and Design, Singapore; 5Center for Frontier Medical Engineering, Chiba University, Chiba, JapanCorrespondence: Wenwei YuGraduate School of Science and Technology, Building1-501, Yayoi-Cho, Inage-Ku, Chiba, 263-8522, JapanTel/Fax +81 043 290 3231Email [email protected]: Few investigations have been conducted on the selective stimulation of small-radius unmyelinated C nerves (C), which are critical to both the recovery of damaged nerves and pain suppression. The purpose of this study is to understand how an anodal pulse in an anodal-first stimulation could improve C-selectivity over myelinated nociceptive Aδ nerves (Aδ) and to further clarify the landscape of the solution space.Materials and Methods: An adapted Hodgkin–Huxley (HH) model and the McIntyre–Richardson–Grill (MRG) model were used for modeling C and Aδ, respectively, to analyze the underlying ion dynamics and the influence of relevant stimulation waveforms, including monopolar, polarity-symmetric, and asymmetric pulses.Results: The results showed that polarity asymmetric waveforms with preceding anodal stimulations benefit C-selectivity the most, underlain by the decrease in the potassium ion current of C.Conclusion: The optimal parameters for C-selectivity have been identified in the low-frequency band, remarkably benefiting the design of selective stimulation waveforms for the recovery of damaged nerves and pain management.Keywords: anodal-first stimulation, C-selectivity, ion dynamics, polarity-asymmetric waveforms
