Which tDCS Protocols Actually Work?
Transcranial direct current stimulation (tDCS) involves applying a low level electrical current to specified brain regions to modulate the neural circuits/highways in the brain (What is tDCS?). By electrically stimulating or inhibiting different regions of the brain, the hypothesis is that one can stimulate or inhibit specific neural circuits, and hypothetically strengthen or weaken those circuits over time (see my article on Neuropriming). There is a growing body of evidence that supports the effectiveness of tDCS in various psychiatric and neurological disorders. There are also studies that suggest that tDCS can enhance cognitive functions in healthy individuals.
There are many tDCS protocols using different montages for various purposes. Remember that a ‘montage’ is the manner in which the electrodes are placed on the head. Electrodes should be placed on the head with precision to ensure that the desired region(s) of the brain is being stimulated. Precision of electrode placement is obtained by using a head measuring system called, the “10-20 System.”
Certain montages have been studied more than others. For some of these montages, there is significant evidence that they are probably effective for their desired purpose. For other montages, there is sufficient evidence in the scientific literature to support that they probably do not work. And then, there are other montages which have not been studied enough to show whether they work or not (Side note - one must always be aware of publication bias in the tDCS brain stimulation world because many negative results have not been published, resulting in a plethora of positive tDCS effect publications.).
This article summarizes which montages have sufficient evidence to show that they probably work (no montages have sufficient evidence to show that they definitely work).
The second part of the article summarizes the montages that probably are not effective based on knowledge acquired through many studies. If you are interested in more detailed information see this publication.
Protocols that have sufficient evidence to show they are probably effective:
Major Depressive Episode, not resistant to medical therapy: Anodal tDCS of left dorsolateral prefrontal cortex (DLPFC) (F3) and cathodal stimulation of the right orbitofrontal region (Fp2)
Addiction/craving in drug addiction, obesity, and eating disorders: Anodal tDCS of the right DLPFC (F3) and cathodal stimulation of the left DLPFC (F4).
Fibromyalgia/chronic pain: Anodal tDCS of left primary motor cortex (C3) and cathodal tDCS of the right orbitofrontal region (Fp2)
Protocols that have sufficient evidence to show they are probably not effective:
Major Depressive Episode, resistant to medical therapy: Anodal tDCS of left DLPFC (F3) and cathodal tDCS of right orbitofrontal region (Fp2)
Tinnitus: Anodal tDCS of left temporo-parietal cortex (between C3 and T5, or between C3 and T3) and cathodal stimulation of right supraorbital region (F8).
Protocols that do not have enough data to demonstrate efficacy:
Note: this does not mean necessarily that these protocols are not effective, only that there is not enough data to show whether or not they are effective.
Major Depressive Episode: Anodal tDCS of left DLPFC (F3) and cathodal tDCS of the right DLPFC (F4).
Obsessive Compulsive Disorder: Preliminary studies of tDCS for OCD are promising, however further evaluation with randomized control trials are necessary. (Anodal tDCS of left DLPFC (F3) and cathodal tDCS Fp2; Anodal stimulation left Supplementary Motor Cortex (SMA) or pre-SMA and cathodal stimulation of Fp2 or right deltoid.)
Alzheimer’s Disease: Anodal tDCS of left DLPFC (F3) or left temporal cortex (T3) and cathodal tDCS of right supraorbital region (Fp2) or right deltoid muscle
Aphasia (word-finding difficulties): Anodal stimulation of left Broca’s area (between T3-Fz and F7-Cz) and cathodal tDCS right supraorbital region (Fp2)
Motor deficits in stroke: Cathodal stimulation of contralesional motor cortex (C3 or C4) and anodal stimulation of opposite supraorbital region (Fp2/Fp3)
Schizophrenia - Although preliminary results indicate that tDCS is a promising technique in treatment of schizophrenia, the current evidence is not robust enough. More trials are needed to further evaluate.
For more detailed information about research consensus of the tDCS protocols above, refer to this research article.
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Disclaimer: Brain augmentation techniques such as those described in our website are not reviewed or approved by the FDA. The long-term consequences of tDCS may not be well understood. However, we accept that use of these techniques occur, and we believe that offering responsible, harm-reduction, and scientifically-recognized information is imperative to keeping people informed. For that reason, the articles, guides, courses, and videos in our website are designed to expand knowledge of those who decide to pursue/research these techniques.
The information and devices displayed on this site are not intended to treat, cure, or prevent any medical disease, and this article is not considered to be medical advice. If a reader decides to purchase and use a tDCS machine, it is his or her responsibility to use it correctly and safely and ensure that it works correctly.