Shockingly, DARPA’s Brain Stimulator Might Not be Complete Nonsense

Where does your mind jump when you hear the mention of electroshock therapy? The use of electrical current to treat various medical conditions has a long and controversial history. Our fascination with the medical applications of electricity have produced everything from the most alarming of patent medicines to life-saving devices like pacemakers and the Automatic External Defibrillator.

The oldest reference I could find is the use of the torpedo fish to allegedly cure headaches, gout, and so on in 43 CE. Incidentally, Torpedo torpedo is an awesome species name.

Dosage: Apply live fish as needed to face? Source

Much more recently, there has been interest in transcranial direct current stimulation (tDCS). In essence, it’s a technique by which you pass an electrical current (typically about 2 milliamps) between strategically positioned electrodes on your head. The precise reason to do this is a bit unclear; different journal articles have suggested improvements in cognition, learning, and/or the potential treatment of various diseases.

I think most of us here spend a lot of time studying. The idea that a simple, noninvasive device can accelerate that is very attractive. We’ve covered a few people building their own such devices.

Unfortunately, what we want to be true is irrelevant. Superficially, this looks like a DARPA-funded panacea with no clearly established mechanism of action. Various commercial products are being sold that imply (but as usual, don’t directly state) that tDCS is useful for treating pretty much everything, with ample use of ‘testimonials’.

While tDCS can be prescribed by a physician in some countries to complement a stroke rehabilitation regime, for off-label purposes you may as well just go apply a fish to your face. Let’s dig into the literature and products that are out there and see if we can find the promise hiding amidst the hype.

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Transcranial Electrical Stimulation With Arduino, Hot Glue

The advance of electronic technology has been closely followed by the medical community over the past 200 years. Cutting edge electronics are used in medical imaging solutions to provide ever greater bandwidth and resolution in applications such as MRI machines, and research to interface with the human nervous system continues at a breakneck pace. The cost of this technology – particuarly in research and development – is incredibly high. Combine this with the high price of the regulatory approvals necessary for devices which deal in terms of life and death, and you’ll find that even basic medical technology is prohibitively expensive. Just ask any diabetic. On the face of things, there’s a moral dilemma. Humanity has developed technologies that can improve quality of life. Yet, due to our own rules and regulations, we cannot afford to readily distribute them.

One example of this is that despite the positive results from many transcranial electrical stimulation (TCS) studies, the devices used are prohibitively expensive, as are treatment regimens for patients. Realising this, [quicksilv3rflash] decided to develop a homebrew, open source transcranial electrical stimualtion device, and published it on Instructables. Yes, that’s the world we’re now living in.

It’s important to publish a warning here: Experimenting with this sort of equipment can easily kill you, fry your brain, or have any number of other awful results. If you don’t have a rock solid understanding of the principles behind seperate grounds, or your soldering is just a little sloppy, you don’t want to go anywhere near this. In particular, this device cannot be powered safely by a wall-wart.

To be honest, we find it difficult to trust any medical device manufactured out of modules sourced from eBay. But as a learning excercise, there is serious value here. Such a project requires mastery of analog design to avoid dangerous currents being passed to the body. The instructions also highlight the importance of rigorously testing the device before ever connecting it to a human body.

The equipment is based around an Arduino Nano receiving commands from a computer over serial, fed by an application written in Python & PyGame. To think, this writer thought he was being bold when he used it to control a remote control car! The Arduino Nano interprets this data and outputs it over SPI to a DAC which outputs a signal which is then amplified and fed to the human brain courtesy of op-amps, boost converters and sponge electrodes. The output of the device is limited to +/-2.1mA by design, in accordance with suggested limits for TCS use.

It should be noted, [quicksilv3rflash] has been experimenting with homebuilt TCS devices for several years now, and has lived to tell the tale. It’s impressive to see a full suite of homebrew, opensource tools being developed in this field. [quicksilv3rflash] reports to have not suffered injuries from the device, and several devices have been shipped to redditors. We’ve only found minimal reports on people receiving these, but nothing on anyone actually using the hardware as intended. If you’ve used one, get in touch in the comments.

It goes without saying – this sort of experimentation is dangerous and the stakes for getting it wrong are ludicrously high. We’ve seen before what happens when medical devices malfunction – things get real ugly, real fast. But hackers will be hackers and if you were wondering if it was possible to build a TCS device for under $100 in parts from eBay, well, yes. Yes it is.