tDCS – The Must-Have Tool of the 21st Century?

I’ve been completely fascinated by tDCS since I first learned of it a couple of months ago. What other technology is so simple yet has the potential to help so many – whether it be to treat depression, Alzheimer’s, ADHD, or just dramatically improve the ability to learn almost anything. What else does all of that with almost no risk or side-effects? Why this isn’t the lead story on the evening news and your local paper is hard to explain.

(A commercial tDCS device and electrodes.)

There are dozens of published scientific studies of tDCS and more than a hundred new studies underway. Consider this: “Air Force researchers were able to cut training time in half during instructional sessions on video simulators using tDCS. Utilizing an Army battle-training simulation video which requires soldiers to detect signs of danger in a landscape of dilapidated buildings and abandoned cars, and scan for things such as explosive devices and enemy gunmen, the tDCS group showed twice the improvement over a short period of time.” (From …Or this: “Stimulating the brain with a weak electrical current is a safe and effective treatment for depression and could have other surprise benefits for the body and mind, a major Australian study of transcranial Direct Current Stimulation (tDCS) has found.” (From

Briefly, tDCS involves running a tiny current (1 to 2 milliamps) through the skull via saline soaked sponges. For healing, typically a daily 20 minute treatment is repeated for 30 or 60 days – though there is wide variation depending on the objective of the treatment. Learning session may involve 30 minutes of tDCS once per day. Enhanced learning continues for up to hours after the tDCS session has ended. Studies show enhanced retention months later.

Because buying a tDCS unit normally requires a prescription and commercial units cost many hundreds or thousands of dollars, lots of amateurs have taken to building their own units – typically for $20 – $100. The best, very simple tDCS design I’ve seen is below – but there are probably plenty I am not aware of. The design below uses a type 23a small 12 volt battery instead of the more common 9 volt battery.

(Simple tDCS design using parts commonly available on the web.)

Where to place electrodes is another interesting aspect of tDCS. Functional maps of the brain are commonplace, so electrode placement is fairly well pinned down. There are many articles on the web that describe electrode placement in great detail. The diagrams below represent the best simple summary of popular electrode placements that I have seen. I do not know who created them – they show up in several places on the web. (I’d be happy to give credit or a link.)

(From the web)
(From the web)
(From the web)

(From the web)

Finally, there are interesting questions about tDCS that educators will have to deal with in the coming years. tDCS, as a learning technology, has been clearly shown to improve learning speed and retention in significant ways. High-schoolers and college students are figuring this out (see YouTube and elsewhere.) So how will we advise young people when it comes to tDCS use? Will students check out tDCS units like they would a laptop from the school media center? What about students who use it and excel vs. students who don’t and struggle? (A new kind of haves and have-nots.) There is a whole range of questions that will have to be tackled – tDCS WILL become a factor in the world of education – soon.

(It’s already happening. Scientific American. From the web.)

For anyone interested in tDCS, my best recommendation is to read, read, read. There is a wealth of information on the web and more appearing constantly as new experiments are performed and studies are published. Stay tuned, this is important!


5 thoughts on “tDCS – The Must-Have Tool of the 21st Century?

  1. Hello SpeakWisdom,

    I started learning about tDCS earlier in the year. And I agree with you, I cannot understand why the mobs are not breaking down the door of the FDA demanding that they allow commercial (read safety certified) devices.

    I went a little farther and began designing one myself (I’m using my prototype right now actually). I will have a manufactured unit in a month or two (see To sell to who, I am not sure yet.

    The regulation process to expect would be FDA regulation of tDCS devices for clinical use (which would require a doctors note). And the device acceptance could cost 10’s maybe 100’s of thousands of dollars; a process that a small company like mine could not undertake.

    Although this may be different. Because of the potential benefits, and such a relatively low cost to product (real devices should run about $200-$500), there may be a thriving “black market” or more demand for the FDA to move faster. It should be interesting…

    Oh yeah, regarding your design in this blogpost, it will work, but without any true current regulation, there will be a need to adjust the potentiometer every time you put the electrodes on as the resistence of the electrodes/head varies greatly between treatments and within treatments. I use current regulating diodes, they output the same current with a varying input and a varying load.

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