Non-rectangular waveforms for neural stimulation with practical electrodes.

Document Type

Article

Publication Date

1-1-2007

Abstract

Historically the rectangular pulse waveform has been the choice for neural stimulation. The strength-duration curve is thus defined for rectangular pulses. Not much attention has been paid to alternative waveforms to determine if the pulse shape has an effect on the strength-duration relation. Similarly the charge injection capacity of neural electrodes has also been measured with rectangular pulses. In this study we questioned if non-rectangular waveforms can generate a stronger stimulation effect, when applied through practical electrodes, by minimizing the neural activation threshold and maximizing the charge injection capacity of the electrode. First, the activation threshold parameters were studied with seven different pulse shapes using computer simulations of a local membrane model. These waveforms were rectangular, linear increase and decrease, exponential increase and decrease, Gaussian, and sinusoidal. The chronaxie time was found to be longer with all the non-rectangular pulses and some provided more energy efficient stimulation than the rectangular waveform. Second, the charge injection capacity of titanium nitride microelectrodes was measured experimentally for the same waveforms. Linearly decreasing ramp provided the best charge injection for all pulse widths tested from 0.02 to 0.5 ms. Finally, the most efficient waveform that maximized the charge injection capacity of the electrode while providing the lowest threshold charge for neural activation was searched. Linear and exponential decrease, and Gaussian waveforms were found to be the most efficient pulse shapes.

Identifier

47049107739 (Scopus)

Publication Title

Journal of Neural Engineering

External Full Text Location

https://doi.org/10.1088/1741-2560/4/3/008

ISSN

17412560

PubMed ID

17873425

First Page

227

Last Page

233

Issue

3

Volume

4

Grant

R21NS050757

Fund Ref

National Institute of Neurological Disorders and Stroke

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