Addressing the inconsistent electric fields of tDCS by using patient-tailored configurations in chronic stroke

Implications for treatment

Journal article (2022)

Authors

J. Van der Cruijsen Biomechatronics & Human-Machine Control - Mechanical, Maritime and Materials Engineering , Radboud University Medical Center, Erasmus MC
R.F. Dooren Precision and Microsystems Engineering , Erasmus MC
A.C. Schouten University of Twente, Biomechatronics & Human-Machine Control - Mechanical, Maritime and Materials Engineering
Thom F. Oostendorp Radboud University Medical Center
Maarten A. Frens Erasmus MC
G.M. Ribbers Erasmus MC, Biomechanical Engineering
Frans van der Helm Northwestern University, Biomechatronics & Human-Machine Control - Mechanical, Maritime and Materials Engineering
Gert Kwakkel Amsterdam UMC, Northwestern University
R.W. Selles Erasmus MC
Research Group
Biomechatronics & Human-Machine Control (Mechanical, Maritime and Materials Engineering) (TU Delft)
Copyright: © 2022 J. van der Cruijsen, R.F. Dooren, A.C. Schouten, Thom F. Oostendorp, Maarten A. Frens, G.M. Ribbers, F.C.T. van der Helm, Gert Kwakkel, R.W. Selles
DOI: https://doi.org/10.1016/j.nicl.2022.103178
More Info
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Published Date

2022

Language

English

Faculty

Mechanical, Maritime and Materials Engineering

Department

Biomechanical Engineering

Research Group

Biomechatronics & Human-Machine Control

Abstract

Transcranial direct current stimulation (tDCS) is a promising tool to improve and speed up motor rehabilitation after stroke, but inconsistent clinical effects refrain tDCS from clinical implementation. Therefore, this study aimed to assess the need for individualized tDCS configurations in stroke, considering interindividual variability in brain anatomy and motor function representation. We simulated tDCS in individualized MRI-based finite element head models of 21 chronic stroke subjects and 10 healthy age-matched controls. An anatomy-based stimulation target, i.e. the motor hand knob, was identified with MRI, whereas a motor function-based stimulation target was identified with EEG. For each subject, we simulated conventional anodal tDCS electrode configurations and optimized electrode configurations to maximize stimulation strength within the anatomical and functional target. The normal component of the electric field was extracted and compared between subjects with stroke and healthy, age-matched controls, for both targets, during conventional and optimized tDCS. Electrical field strength was significantly lower, more variable and more frequently in opposite polarity for subjects with stroke compared to healthy age-matched subjects, both for the anatomical and functional target with conventional, i.e. non-individualized, electrode configurations. Optimized, i.e. individualized, electrode configurations increased the electrical field strength in the anatomical and functional target for subjects with stroke but did not reach the same levels as in healthy subjects. Considering individual brain structure and motor function is crucial for applying tDCS in subjects with stroke. Lack of individualized tDCS configurations in subjects with stroke results in lower electric fields in stimulation targets, which may partially explain the inconsistent clinical effects of tDCS in stroke trials.