Optimal electrode placement in transcranial direct current stimulation via genetic algorithm

Transcranial direct current stimulation (tDCS) is thought to be more appropriate for stimulating deeper brain areas rather than conventional techniques. Effectiveness of tDCS, however, strongly depends on electrode positions and the amount of injected currents. This paper is aimed to apply the genetic algorithm method for determining optimal location of electrodes and relative injected currents in a multiple electrode scheme. The objective of the presented technique is to maximize average magnitude of current densities delivered to the target area. Here, a 3D finite element method in ANSYS software package is employed for calculating delivered current densities. The proposed approach also considers safety constraints such as maximum allowed current injection. The effectiveness of the proposed algorithm is demonstrated through a standard four-layer head model. Owing to the results, the presented approach provides a promising tool for neurologists to stimulate patients more effectively.