Surface EEG-Transcranial Direct Current Stimulation (tDCS) Closed-Loop System

Jorge Leite, Leon Morales-Quezada, Sandra Carvalho, Aurore Thibaut, Deniz Doruk, Chiun-Fan Chen, Steven C. Schachter, Alexander Rotenberg, Felipe Fregni
2017 International Journal of Neural Systems  
Conventional tDCS protocols rely on applying electrical current at a fixed intensity and duration without using surrogate markers to direct the interventions. This has led to some mixed results; especially because tDCS induced effects may vary depending on the ongoing level of brain activity. Therefore, the objective of this preliminary study was to assess the feasibility of an EEG-triggered transcranial direct current stimulation (tDCS) system based on EEG online analysis of its frequency
more » ... . Six healthy volunteers were randomized to participate in a double-blind sham-controlled crossover design to receive a single session of 10 min 2mA cathodal and sham tDCS. tDCS trigger controller was based upon an algorithm designed to detect an increase in the relative beta power of more than 200%, accompanied by a decrease of 50% or more in the relative alpha power was used based on baseline EEG recordings. EEG-tDCS closed-loop-system was able to detect the predefined EEG magnitude deviation and successfully triggered the stimulation in all participants. This preliminary study represents a proofof-concept for the development of an EEG-tDCS closed-loop system in humans. We discuss and review here different methods of closed loop system that can be considered and potential clinical applications of such system.
doi:10.1142/s0129065717500265 pmid:28587498 fatcat:l6kabbs2zva2porvsrdic3j6c4