Variability of E-field in Dorsolateral Prefrontal Cortex Upon a Change in Electrode Parameters in tDCS.

Abstract

Transcranial direct current stimulation (tDCS) is a part of the transcranial electrical stimulation method widely used for treating patients with neurological and psychological abnormalities, along with application in cognitive improvements. With a simple design and operating procedure, tDCS is considered a safe and effective therapy choice. With predefined treatment protocols, it is possible to achieve the required electric field within the inner structures of the brain to excite and inhibit neuronal activity and its outcomes. The generated electric field shows variation among individuals due to anatomical and functional changes in the brain tissues. In-situ modeling of therapeutic procedures can help to assure the probabilistic outcome of tDCS. In this study, we have obtained results for electric field strength variability in a cognitively normal subject. We have simulated the subject with variation in stimulating electrode size and shape, a combination of electrode-Gel and electrode-sponge with SimNIBS Ver (3.2.6), and measured electric field strength and focality. Simulated results show less dependence on gel or sponge thickness and more reliance on electrode size and shape for E-field and focality. The increasing size of electrodes reduces electric field strength and focality with asymmetrical E-field distribution, whereas decrement generates a more symmetrical and focused E-field with higher strength.