Thoughts on the Use of tDCS in Education Settings

Why the Interest in tDCS?

Research studies and anecdotal evidence show that tDCS, a simple and safe way to stimulate the brain, does have the ability to enhance memory, speed learning, improve physical skill, and enhance creativity.  There are now well over 1,000 published studies of tDCS with more underway and research participation of institutions ranging from Harvard Medical, MIT, Emory University, to the University of Alabama and dozens more.


(tDCS headset. http://www.foc.us)

Already, high-school and college students are catching on to just what tDCS may do for them.  There are many YouTube and blog posts from and by students discussing their experience with tDCS and others asking for help in setting up and using a tDCS device.  Some indicate substantial improvement in their performance with tDCS. As tDCS devices become more accessible and word of it continues to spread through popular press and internet resources (NYT, Nature, Scientific American and many others have already published tDCS articles), educators can eventually expect to be confronted with some significant ethical and policy questions.

While it’s difficult to pin-down an exact percentage improvement students see in their work, (more studies are required), students use words like “significant”, “substantial”, and “surprising” in their comments. As time goes on, not only will more students demand access to tDCS, it is likely that parents, seeking greater success for their children, will encourage its use.

How Might tDCS Be Used by Students

  • During study for tests – including high-stakes (SAT, etc.)
  • Learning lists of material (names, dates, places, events, etc.)
  • Learning new languages (spoken and written)
  • Improving athletic skill
  • Enhancing creativity in writing, art, film production, etc.
  • To reduce or eliminate depression (a common problem in student populations)

Ethical Issues

Educators must face the reality that certain students will “brain boost” using tDCS and by doing so, improve their classroom performance as well as on assorted tests that are common in education settings. Even “high-stakes” test outcome could be positively influenced for students making proper use of tDCS. Student athletes may use tDCS to improve their performance on the tennis court or football field.

  • If a student using tDCS for study can perform 10% better on an SAT test than an equally talented student who does not possess a tDCS device, is there a fairness or ethical issue?
  • If a student has a learning disability and through the use of tDCS is able to perform at “non-disability” levels, is there a fairness or ethical issue?
  • Will we now enter a new era of “haves and have not’s” in K-12 and higher-education learning?
  • Will students from middle-class and above families, able to afford a device and related training, take advantage of it while lower income, less advantaged students will go without?

If tDCS, well used, can improve test scores, is that not ultimately going to be very significant in the lives of some students?


(George Mason University)

Policy Questions

If tDCS is going to play some role in the lives of K-12 and higher ed students in the coming years, then perhaps it’s time to begin creating policy to address tDCS – including:

  1. Will tDCS use be permitted (even though it will be impossible to regulate home use)?
  2. Will students be trained in proper tDCS use in school? (or after school)
  3. Will schools provide tDCS devices for students when the family cannot afford it?
  4. Will schools encourage tDCS as a means to improve test scores?
  5. Will school clinics offer tDCS treatments for those suffering with depression (rather than medicate them?)
  6. Will legal liability issues limit the ability of schools to responsibly encourage and direct the use of tDCS in education settings?

tDCS is a wonderful thing! It has the potential to help the human condition on so many levels – from depression to Parkinson’s disease, with learning enhancements thrown in as a bonus. How will we, as educators, respond to this fascinating new capability – which students have already discovered?

Let the dialog begin!

Contact me via brent@speakwisdom.com

For more information on tDCS see www.speakwisdom.com, http://www.diytdcs.com, http://www.transcranialbrainstimulation.com, http://www.pubmed.gov, and Google!

Can a 9 Volt Battery Save A Life – Even Yours?

 

A 9 Volt Battery???

It’s becoming very clear that persons with serious brain related issues can, in many cases, be very effectively treated with the simple application of an extremely low current to the scalp, sourced from a common battery! Nothing painful, exotic, complicated, or dangerous is involved. Yes, transcranial direct current stimulation (tDCS) can be used to treat depression, chronic pain, and is being researched as an aid for Parkinson’s and Alzheimer’s patients. But TDCS has also been shown to be an effective way to speed learning, ease memorization, and enhance creativity. As an example of how far ranging tDCS use is, the US Air Force and Army have apparently been using tDCS techniques to improve cognitive capabilities for years!


(Scientific American)

I’ve been completely fascinated by tDCS since I first learned of it. What other technology is so simple yet has the potential to help so many – whether it be to treat depression, chronic pain, or just dramatically improve the ability to learn or memorize 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.

Think this is all hocus-pocus? Many big name research institutions around the world are now involved in tDCS including MIT, Harvard Medical School, Emory University, University of Michigan, the Spaulding Rehabilitation Hospital,  Massachusetts General Hospital, University Medicine Berlin, The City College of New York and many more. A quick look at http://www.pubmed.gov will reveal that over 900 studies of tDCS have now been published!

What is the treatment?

tDCS basically involves using a tiny amount of energy from a battery applied in particular locations on the scalp, depending on the effect desired. A one or two milliamp ( 0.001 amp) direct current is applied via saline-wetted sponges to two points on the head. For example, for depression the negative lead is placed just above the right eye on the forehead and the positive lead goes high on the left-forehead.) For depression, typical treatment lasts about 20 minutes once a day for about 30 days and the person receiving the treatment feels nothing other than a slight tingle. Treatment can easily done at home. That’s it. No expensive medications with unpredictable results and terrible side effects. It works! Wow! Big pharma is not going to be happy about this!

tDCS treatment hardware is so simple that people (sometimes desperate for help and at the end of their rope) are building their own tDCS treatment systems (about $50 in parts at Radio Shack will do! Instructions are on the web.)

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(An example tDCS device built by the author)

While assembled tDCS equipment sold by vendors in the US normally requires a prescription (raising the price to $300 or more), the safety record of tDCS has caused the FDA and suppliers to “look the other way” allowing a number of vendors to now begin offering tDCS equipment directly to individuals. For example, a company by the name of foc.us has recently started shipping a feature laden tDCS headset which sells for about $250.  

There are doctors and clinics now offering tDCS services. Transcranial Direct Current Stimulation (tDCS) is a safe, non-invasive therapy for treatment-resistant neurologic, psychiatric and chronic pain disorders. You can increase memory and learning with tDCS, too. Effective, easy-to-do, inexpensive and without side effects, tDCS can be done in the outpatient clinic or, for the appropriate patient, in the home which provides obvious advantages.

So, Can a 9 Volt Battery Save a Life – Even Yours?

The Centers for Disease Control reports that about 10% of Americans are clinically depressed and either on medication or in need of it.  Also, about 40,000 people per year commit suicide in the US! This huge depression/suicide problem is not being effectively addressed because many who need treatment will not seek it out.  Why? There are several possible reasons including the stigma of depression and its treatment, lack of access to appropriate care, the high cost of treatment and medications, etc. tDCS is inexpensive, simple, side-effect free, and shown to have positive effect in many scientific studies. In my opinion, It should be in the “tool kit” of every doctor and mental health professional.

I’ll close for now and provide you with some links to investigate. tDCS looks to be a bombshell that could literally transform the lives of many, many people. It probably deserves your awareness!

To get you started: 


I have a large number of tDCS related articles and links on my website:

www.speakwisdom.com

General Interest Wikipedia Article:

http://en.wikipedia.org/wiki/Transcranial_direct-current_stimulation

tDCS – Scientific American and the Air Force:

http://www.scientificamerican.com/article.cfm?id=amping-up-brain-function

General Interest Article with Many References

http://www.mindalive.com/articlenten_Transcranial_DC_Stimulation.htm

British Journal of Psychiatry:

http://bjp.rcpsych.org/content/200/1/52.abstract

http://bjp.rcpsych.org/content/200/1/10.abstract

Interesting Video and Text about Electrode Positioning:

http://www.jove.com/video/2744/electrode-positioning-montage-transcranial-direct-current

tDCS Headset:

www.caputron.com

Links to more tDCS information

http://www.diytdcs.com

DIY tDCS Safety Standards

The do-it-yourself transcranial direct current stimulation (DIY tDCS) community is growing in numbers and sophistication – particularly as new studies are published and tDCS devices emerge in the marketplace.  It may be time to be a bit more proactive in providing safety information to many who will become curious enough about tDCS to want to try it.

I’d like to propose DIY tDCS Safety Standards (better name welcome).  Below is a draft for your comment.  Perhaps if we can get some agreement on content and wording, those of us who publish tDCS blogs and websites as well as vendors could consider posting it somewhere on their site.

By proposing this code of safety, I’m not encouraging anyone to try tDCS, but I know it’s happening – so guidance is appropriate and necessary.

DRAFT DRAFT DRAFT (Your comments welcome. I’ll repost blog this as I edit it with your suggestions.)

DIY tDCS Safety Standards

As a potential or current do-it-yourself tDCS user I agree to the following:

1.   I will, if reasonably possible, seek out a medical professional for tDCS advice, treatments and follow-up.

2.   If I have cranial scar tissue, an implant, or other unusual medical condition, I will seek clearance from my doctor before using tDCS. If I have a seizure disorder I will refrain from using tDCS or use it only under direct supervision of qualified medical personnel.

3.   I will not, under any circumstances, directly connect a battery to my head. I understand that I could greatly exceed the maximum 2 mA current limit used by tDCS researchers, possibly harming myself in the process.

4.   I understand that electronic components can fail unpredictably. For this reason, I will never plug a tDCS device directly or indirectly into an electrical outlet. I understand that by doing so a simple component failure could result in death (or worse).

4a. If I do not have a solid understanding of electrical and electronic concepts, components, and procedures, I will not attempt to build a tDCS device.

5.   I will not exceed 30 minutes in a tDCS session. This is the maximum used in tDCS research. I will use the “buddy system” and never proceed with a tDCS session without someone else present who is familiar with the shutdown process for my tDCS device – or who can at least remove electrodes and summon additional help should that be necessary.

6.   I will use some means to verify the current level being produced by my tDCS device. This could be from a built-in ammeter or an external digital volt meter (DVM). I will never exceed the 2 mA limit used by tDCS researchers.

7.   I will use electrode placements that have been studied and published by respected researchers and not simply guess or experiment with electrode placement. I will do my best to stay abreast of tDCS research and development.

8.   If I detect any undesirable effect from tDCS, I will immediately cease use until the cause is clearly understood and corrected.

9.   I will not experiment on friends, family, associates, or others. It is up to each individual to read, research, and understand the risks, benefits, and limitations of tDCS and make their own decision about its appropriateness to their situation, preferably in consultation with a medical professional. I will never use tDCS on children or animals.

10. I understand that, with regard to DIY tDCS and any actions I might take, I am responsible for my own well-being and above all else, safety and wise decisions will be my primary concerns.

My tDCS Wish List

I have been reading studies, attending training, experimenting with, and writing about transcranial direct current stimulation (tDCS) for about two years now.  Needless to say, I am enthusiastic about what tDCS can do for many people who use it for depression, chronic pain, enhanced creativity, and memory. It may also may have positive effect for other important conditions such as stroke, Parkinson’s and Alzheimer’s – there are certainly studies that show that to be the case.


(Scientific American)

Given that it has positive effect on many who try it, it could improve the quality of life of millions of people around the world. All of this without drugs, without the cost of drugs, and with no significant side-effects.

With all the great things I’ve learned about tDCS, I thought I’d share a little of my tDCS Wish List for the next five years:

In The Next Five Years I Wish That:

  1. every appropriate medical practitioner (and counselor) would at least become aware of tDCS. A treatment this good, this simple, this safe, with so much positive effect should not be overlooked. It should be a tool in the kit of considered-treatments for every practitioner.
  2. that the popular press would at least make an attempt to write sensible and factual articles about tDCS. For example, it would be great to stop comparing tDCS to electro-shock treatment. Could they be any more different? Such mindless hype scares people who might be helped greatly by tDCS.
  3. that funding could be found to “get the word out” about tDCS. Because there are no drug company $ billions for magazine ads, TV commercials, and infomercials, it looks as though tDCS will always be a niche treatment, known by a lucky few – missed by millions it could help. I wonder how many lives could be vastly improved (or saved) if tDCS were as well-known as Viagra?
  4. that I could find one or more well-known, depressed, troubled Hollywood star(s), known for appearances in People Magazine and on TMZ – who would agree to a course of tDCS treatment. Once improved, those stars would have to be willing to speak about tDCS – the treatment that got them out of the pit. For better or worse, we live in a “star” powered society – such articles appearing in Hollywood rags and read and seen by millions could really help push tDCS towards a tipping point.
  5. that my second career be all about researching, writing, and speaking about the practical side of tDCS. There is a whole world full of people who need the help that this simple treatment can offer. A tDCS device can be as simple as a 9 volt battery, an inexpensive CRD diode, and a couple of sponges. Imagine the good that could be done!
  6. that I could find one or more philanthropists willing to join in the good work related to tDCS – and help a whole lot of people in the process! There are $ millions of research dollars flowing to universities and research centers all around the world looking at tDCS. But there is very little being done to get tDCS to the people who can benefit from it. If you are a philanthropist who really wants to make a difference in a very tangible way, feel free to contact me. Let’s get something started!


(One of the most important contributions of tDCS:
a simple treatment for the depression epidemic.)

Mark the date. At this point, for certain types of treatment, tDCS is well researched, simple, and considered safe. We all know that tDCS is barely known among the masses and the medical community. Ask any doctor you know  – I’d say the odds are about 1 in 100 that they know anything at all about tDCS.

What will things be like in 2018? By 2018, how many millions will have suffered for lack of access to a tDCS device and a tDCS trained professional? Can you help?

foc.us-mal-female-london-thumb
(A self-contained tDCS treatment headset. http://www.foc.us)

Just for Fun: tDCS in a Bottle

If you have been reading my blog, you know that I have built a number of tDCS devices – from the simple to the complex. All do basically the same thing – deliver a very low current for the purpose of various tDCS treatments. I mentioned in my last post that Keith Spaulding of http://dcstim.blogspot.com has come up with what must be the simple tDCS design of the decade. It works, too! Keith plans to market a line of tDCS devices and I’ll review his first in my next post.

I decided to borrow Keith’s design one more time and build a simple tDCS device into an old pill bottle, just to show how easy it is to build a current regulated tDCS device – and to show how small they can be. My latest creation could easily be carried in a pocket or tucked in a hat. I call it “tDCS in a Bottle” and yes – I decided to copyright the name – hey why not?

100_1376

My simple circuit consists of a type 23A 12v volt battery, a 2.2 k Ohm resistor, a current regulating diode (CRD), a pill bottle, and some lead wires. You could build one yourself in 15 minutes or less!

100_1360

(Wired and tested tDCS components ready to stuff in a pill bottle. Yes, I did peel the old labels off of the bottle.)

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(Closed up, ready for new labels. Small, very portable, works!)

After I completed construction, I checked regulated current output with a DVM – and plan to do so periodically to verify battery condition.

It’s sort of an ironic twist to build a tDCS device into a pill bottle – just think how many people might be able to get off of pills if tDCS were in wide use by the medical community! Wow! Anyway – “tDCS in a Bottle” works and works well – delivering a current regulated 1, 1.5, or 2 mA depending on which CRD is used.

If anyone is interested in partnering to sell these at the check-out at Walmart, let me know. We could do the country a lot of good! Pharma would not be happy. Think the FDA would be ok with it? 🙂

Disclaimer: As always, your use of any information posted here is at your risk.

A Very Simple Current Regulated tDCS Device

Simple tDCS

The Holy Grail of tDCS seems to be availability of a very simple, current regulated device that is easy to build and use.  Keith Spaulding of http://dcstim.blogspot.com got us about as close as we are likely to get with this design:

simpletdcscctU

I decided to use Keith’s design, with some minor variations, and build a tDCS device.  Keith’s tDCS design is based on using a current regulating diode (CRD).  CRD’s are available in many variations including three values that are of particular interest to DIY tDCS.  They are 1 mA, 1.5 mA, and 2 mA.  You pick the value you desire, build Keith’s circuit and away you go – current limited tDCS.  Here are some plus and minus items to consider:

PLUS

  1. Very simple to build
  2. Current limited by resistor if CRD shorts in failure

MINUS

  1. Current is fixed – you can’t ramp it up or down.
  2. You may see a phosphene at start or end of tDCS session
  3. Keith’s design does not include a meter to confirm current level

I decided to make the following changes to Keith’s design:

1. Use a single type 23A 12 volt battery instead of two 9 volt batteries. This limits CRD failure current to 12 / 2200 = 5.5  mA instead of 8.2 mA in Keith’s design. Neither is dangerous according to studies published on the web. Both would be very irritating and immediately noticable to a user! I do use a 9 volt battery to power the display (below). You can expect 3-6 months of battery life from the type 25a tDCS battery and a year or more from the 9 volt display battery given regular use.
2. Added a digital mA panel meter so that actual current delivered can be monitored
3. Added a DPST switch to act as an on-off switch for the tDCS circuit and on-off for a separate battery and resistor to power the meter.  The digital meter I purchased needs 5 volts to operate. I use a 9 volt battery with a 1 k Ohm resistor in series to achieve the desired operating voltage.

Before I built a “permanent” CRD tDCS device, I built a test unit using a breadboard.

000_0007

The type 23A battery is at the left side of the pic, the leads that go to the sponge electrodes are at the right.  Follow the red lead from the battery and you will see the CRD. It’s tiny! In the breadboard example I used two 1 k Ohm resistors (what I had handy), one in series with the plus lead of the battery and one in series with the negative lead (instead of a single 2 k Ohm resistor in series with the plus lead.  Either method is fine.)  I also threw in a 100 uF capacitor (the blue cylinder) across the leads to the sponges to ease start-up and shut-down current.  I did away with it in the final build – it didn’t seem that helpful.

000_0012

Close-up of the CRD.  Note the black band is away from the plus of the battery. I decided to use a 1.5 mA CRD.  Why?  Studies posted on the web show that 2 mA is better than 1 mA for treatment effectiveness.  However, it is my experience that 2 mA irritates the skin of many individuals causing them to cease using tDCS.  As odd as it seems, backing the current off to 1.5 mA reduces reports of irritation to almost zero.

For the final build, I used a RS project box I had on hand.  You could build a CRD based tDCS device into something much smaller and more attractive.

000_0024

In the bottom left is the digital mA meter circuit. To its right is a DPST switch. The left portion of the switch is used as on-off for the meter.  A 1 k Ohm resistor is in series with a 9 volt battery and the switch to provide the 5 volts needed by the meter.  The right portion of the switch is the on-off connecting the 12 volt type 23a battery to the series connected 2.2 k Ohm resistor, the CRD and the electrodes. You can see the CRD at top-center of the pic, just before I placed heat-shrink tubing over it to protect it.

000_0026

Wires dressed, ready to close up the box.

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Completed unit with electrodes attached shows it’s regulated current level, 1.5 mA.

So Where Do the Parts Come From?

The case, switch, resistor, battery clips, heat-shrink tubing, and leads all come from Radio Shack. The CRD came from www.mouser.com. I used PN 954-E-152, a 1.5 mA CRD with axial leads.  Be careful not to buy a surface-mount device unless you are well prepared to deal with one. The “3 digit Mini Blue LED DC 100mA meter” came from “Coldfusionx” via EBay.  They are in California – not China – so delivery was quick. I use Amrex electrodes which are available via Amazon and other suppliers.

By the way, I found the meter, as delivered, to be slightly out of calibration (it read too high).  I was able to check and recalibrate  it (adjustment screw) against a couple of DVMs.

Total cost for this project was about $50.

Wrap-Up

Keith’s design is as simple as it gets.  If you want more flexible current control, you could add a selector switch and CRDs of different values – or you could use one of the many LM device designs on the web and build a tDCS device with fully variable control.  Either way, tDCS is an amazing and wonderful thing.  Please proceed with caution and read all that you can before attempting to build your own device – especially read safety related articles and papers!  Best of all would be for you to seek out a medical professional like www.transcranialbrainstimulation.com .

Disclaimer

The information presented in this article represents an accumulation sourced from articles, papers, popular press, and other sources easily accessed on the internet. While evidence so far indicates that tDCS is very safe, your use of information in this article is completely at your risk. You are  advised to seek out a trained medical professional for assistance with tDCS.

#4 in the YouTube Series: Treating Depression with tDCS

(Image from the web)

Depression

Depression is a significant national problem affecting individuals and their families and friends.  tDCS has been show to have a positive effect in the treatment of depression. The tDCS treatment is very simple and has trivial side effects.

In this YouTube video, the forth in a series, I present information about treating depression with tDCS.  I hope you will find it useful and pass along what you learn.

http://www.youtube.com/watch?v=qZKGhTa7c1M

 

The tDCS “Cat” is Out of the Bag

Miracle Medication

Aspirin is a miracle medication. Isolated by Hoffman in 1897, it is a simple compound that, these days, can be created by anyone who has had a high-school chemistry course. Aspirin can, of course, be purchased in commercial form and most people are familiar with certain maladies that can be treated by it. On the fringes, there are esoteric uses for aspirin, but in the main, it is well understood and used by millions of people every day.

images

What about transcranial direct current stimulation (tDCS)? It’s simpler and (apparently) safer than aspirin – when used correctly – and is effective in treating depression, chronic pain, enhancing learning and much more in otherwise healthy people. So why can’t the average person on the street buy a tDCS device and self-administer treatment?

20120813-200950.jpg

(neura.edu.au)

There are at least three reasons. First, tDCS is relatively new and studies that confirm its effectiveness and safety are just emerging. Two, certain tDCS treatment scenarios can be pretty complex, well beyond the ability of an average person to carry out. Third, there is no way for big-pharma to cash in on tDCS (yet). It’s very unlikely you will ever see expensive commercials during your favorite TV show advertising tDCS to treat some focus-group tested three-letter malady. It won’t happen. tDCS devices are extremely simple to build (or buy) and treatment protocols for certain ailments ARE simple and are all over the internet.

The average Joe will learn about tDCS and start demanding access to it because a bunch of do-it-yourself (DIY) folks and a few physicians will have succeeded in a grass-roots effort to get the word out. Yes, there is also a small and growing group of doctors that see the obvious benefits of tDCS (and lack of risk) and are starting to use it with their patients – and their patients are becoming some of the best spokes-persons for tDCS.

Problems, Problems

According to the CDC, about 1 in 10 adults in the US uses some form of antidepressant.  Their depression may or may not be well controlled and they likely suffer at least some noticeable side effects. Sources vary, but about $3 billion is spent on antidepressants every year. These numbers do not reflect a significant number of individuals who ARE depressed but not receiving any treatment – due to costs, social pressures, etc.

It’s hard to believe, but various sources report that as many as 1 in 3 Americans suffer from chronic pain.  Cost? $500-600 billion per year!

The tDCS Triad

Transcranial Direct Current Stimulation has been shown to provide relief for depression and chronic pain, and to enhance learning (the tDCS triad) – and much more. When treating the “triad”, it is simple, apparently very safe, and has no significant side effects. Can similar claims be made for any other other treatment (medication)?

Does it work for everyone? The simple answer is no, but for many it does – and for many who failed to get relief (or enhancement) from medications.

tDCS is not just about depression, chronic pain, and learning enhancement. As mentioned above, there are very broad areas of research seeking potential use in treating Alzheimers, stroke, brain trauma, etc. Treatment for those less understood ailments can be quite complex and require MRI or FMRI to design an appropriate regimen and the use of “high definition” tDCS, using ten electrodes or more, as part of the treatment. This is well beyond the ability of the DIY community.

But the “triad” (depression, chronic pain, learning enhancement) is normally treated with simple “bipolar tDCS” – two electrodes are placed in very specific locations on the scalp, which are well known, as part of normal treatment.

Because bi-polar tDCS involves such simple equipment and procedures, a rather sizable “do-it-yourself” community has taken up the mantle of treating themselves and helping friends reap the benefits of tDCS.

DIY tDCS is growing because most doctors have no idea what tDCS is – or what it can do. Further, doctors who do use tDCS cannot bill insurance for tDCS treatments (it is not yet “recognized” by the FDA.) So treatment can be expensive – out of reach for many – and simply unavailable in most areas of the US. So it seems that the DIY community will continue to build tDCS devices, use tDCS to treat the “triad”, and spread the word via emails and blogs. Meanwhile, research centers, Universities, and the like will continue their work on all areas of tDCS using their more sophisticated equipment and techniques to push the boundaries of tDCS application.

tDCS for Everyone?

One day, tDCS may be as commonly used as aspirin for treating certain issues – but we have a long, long way to go to get to that point. Like aspirin, tDCS won’t help everyone – but scientific and anecdotal evidence says it can help many. So while we wait, millions go untreated (or poorly-treated) and live lesser lives due to lack of access to tDCS triad treatments and all the benefits they can bring. Come on medical community, come on FDA.

Very Interesting tDCS Design

I ran into a design for a very simple tDCS device via the http://www.diytdcs.com blog.  It’s by Keith Spaulding and uses a current regulating diode rather that a current regulating IC.  I’ve ordered some CRD’s and will report on building a device in the near future.  This is about as simple as a good tDCS device could get! I will add an on/off selector switch and a ramp up/down capacitor to Keith’s idea. I might also use a type 25A 12v battery just to keep things as small as possible.  Little need for a meter or other circuit complications! Here is his schematic and a link to his blog… Thank you Keith.

http://dcstim.blogspot.com/