Updated Technique for Reliable, Easy, and Tolerated Transcranial Electrical Stimulation Including Transcranial Direct Current Stimulation

Abstract

Transcranial direct current stimulation (tDCS) is a noninvasive method of neuromodulation using low-intensity direct electrical currents. This method of brain stimulation presents several potential advantages compared to other techniques, as it is noninvasive, cost-effective, broadly deployable, and well-tolerated provided proper equipment and protocols are administered. Even though tDCS is apparently simple to perform, correct administration of the tDCS session, especially the electrode positioning and preparation, is vital for ensuring reproducibility and tolerability. The electrode positioning and preparation steps are traditionally also the most time consuming and error-prone. To address these challenges, modern tDCS techniques, using fixed-position headgear and pre-assembled sponge electrodes, reduce complexity and setup time while also ensuring that the electrodes are consistently placed as intended. These modern tDCS methods present advantages for research, clinic, and remote-supervised (at home) settings. This article provides a comprehensive step-by-step guide for administering a tDCS session using fixed-position headgear and pre-assembled sponge electrodes. This guide demonstrates tDCS using commonly applied montages intended for motor cortex and dorsolateral prefrontal cortex (DLPFC) stimulation. As described, selection of the head size and montage-specific headgear automates electrode positioning. Fully assembled pre-saturated snap-electrodes are simply affixed to the set position snap-connectors on the headgear. The modern tDCS method is shown to reduce setup time and reduce errors for both novice and expert operators. The methods outlined in this article can be adapted to different applications of tDCS as well as other forms of transcranial electrical stimulation (tES) such as transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS). However, since tES is application specific, as appropriate, any methods recipe is customized to accommodate subject, indication, environment, and outcome specific features.

Applications of Non-invasive Neuromodulation for the Management of Disorders Related to COVID-19

“…Bifrontal protocols would position the anode over F2, and cathode over the F4 scalp position (10–20 EEG System) or in the bifrontal “OLE” montage which can optimize current delivery to DLPFC ( 11 – 13 ). Targeted tDCS of DLPFC can be achieved using 4x1-tDCS centered over DLPFC ( 142 , 143 ). High-frequency rTMS protocols would target the left DLPFC with 10 Hz, trains of 50 pulses, with intertrain intervals of 25–50 s, at 90–120% of the resting motor threshold, until 3,000 pulses per session, with figure-of-eight coils positioned at the F3 scalp position or using neuronavigation ( 14 ).…”

“…It is suggested that tDCS may be used with the anode positioned at the T3 scalp position, and cathode at the T4 scalp position, with 2 mA for 20 min, using 5 × 5 cm or 5 × 7 cm electrodes, together with exercises directed to respiratory function. For targeted temporal cortex tDCS the 4x1 HD-tDCS can be used ( 142 , 143 ).…”

“…Training should cover sponge preparation, electrode placement, stimulation initiation with ramp up until the target intensity, and standard operating procedures for troubleshooting common problems. Customized head-bands that facilitate electrode positioning and improve compliance could also be provided ( 142 , 220 , 222 ). Parameters used in most clinical trials are similar to what is usually employed in care facility settings ( 220 ).…”

Guidelines for TMS/tES clinical services and research through the COVID-19 pandemic

“…As outlined in case examples (Sections 8.1, 8.2), for those centers already engaged in remote supervised tDCS, strategic and incremental protocols changes allow continuation (and even expansion) of protocols. For those centers exploring transition of in-center tDCS to remotely supervised tDCS, there are well-established principles under the Remote Supervised rubric that allow homebased tDCS with compromising reproducibility [46] and detailed supporting documentation [45,56,65,66].…”

Effectiveness of TES and rTMS for the Treatment of Insomnia: Meta-Analysis and Meta-Regression of Randomized Sham-Controlled Trials

“…It is hypothesized that TES could interfere with slow oscillation in the brain, which could increase the slow wave activity and enhance the lowfrequency electroencephalogram (EEG) activity (i.e., a marker of arousal) (23)(24)(25). Due to its portable features and convenience to use, TES is suitable for self-administration at home (26,27). However, TES is not free of limitations, and it has been criticized for poor spatial accuracy (28).…”