Different pulse shapes to obtain small fiber selective activation by anodal blocking - a simulation study

Vučković, A. , Rijkhoff, N. J. M. and Struijk, J. J. (2004) Different pulse shapes to obtain small fiber selective activation by anodal blocking - a simulation study. IEEE Transactions on Biomedical Engineering, 51(5), pp. 698-706. (doi: 10.1109/TBME.2004.826663)

Abstract

The aim of this study was to investigate whether it is possible to reduce a charge per pulse, which is needed for selective nerve stimulation. Simulation is performed using a two-part simulation model: a volume conductor model to calculate the electrical potential distribution inside a tripolar cuff electrode and a human fiber model to simulate the fiber response to simulation. Selective stimulation is obtained by anodal block. To obtain anodal block of large fibers, long square pulses (>350 μs) with a relatively high currents (1-2.5 mA) are usually required. These pulses might not be safe for a long-term application because of a high charge per pulse. In this study, several pulse shapes are proposed that have less charge per pulse compared with the conventional square pulse and would therefore be safer in a chronic application. Compared with the conventional square pulse, it was possible to reduce the charge with all proposed pulse shapes, but the best results are obtained with a combination of a square depolarizing pulse and a blocking pulse. The charge per pulse was up to 32% less with that pulse shape than with a square pulse. Using a hyperpolarizing anodal prepulse preceding a square pulse, it was not possible to block nerve fibers in a whole nerve bundle and to obtain reduction of a charge per phase. Reduction of the charge could be achieved only with spatially selective blocking. The charge per phase was larger for the combination of a hyperpolarizing anodal prepulse and a two-step pulse than for the two-step pulse alone.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Vuckovic, Dr Aleksandra
• Authors: Vučković, A., Rijkhoff, N. J. M., and Struijk, J. J.
• College/School: College of Science and Engineering > School of Engineering > Biomedical Engineering
• Journal Name: IEEE Transactions on Biomedical Engineering
• Publisher: IEEE
• ISSN: 0018-9294
• ISSN (Online): 1558-2531