I’ve been hearing whispers about TDCS or Transcranial Direct Current Stimulation and related TMS Transcranial Magnetic Stimulation for a while now, but only recently decided to do some digging. The premise is that a small amount of electrical or magnetic stimulation can enhance or reduce the ability of neurons to fire (depending on the polarity). The premise seems plausible as neurons fire in response to tiny changes in the potential across neuronal membranes. There is no shortage of press on the subject. Some good ones include this article in Nature and another one in Wired. Amazingly, peer-reviewed papers back up the fact that TDCS can have a biological effect on people. A fantastic and highly entertaining introduction to TDCS can be heard on the podcast RadioLab.
The technology is almost stupidly simple and this might be its greatest strength and weakness. Basically a TDCS device consists of a 9-volt battery, a variable resistor and some electrodes. People connect the electrodes to various parts of the scalp, face or body and and get a small zap (~1m amp) for about 20 minutes. Users know the machine is on due to a tingling sensation and sometimes a metallic taste in their mouths. Supposedly, depending on the placement of the electrodes different neuronal clusters can be stimulated or repressed. What is really interesting is that people feel a bit different even after stopping TDCS and this might be due to a increase in certain neuronal receptors (like the same ones that respond to drugs like PCP and ketamine). Anecdotal evidence suggests that TDCS is relatively safe with skin irritation and seeing a flash of light depending on where the electrode is placed, being reported, but no long-terms studies have been done.
Because the technology is so accessible almost anyone can build or buy a machine. However this leads to many different machines, protocols voltages, electrode types and placements. This means it is quite difficult for one person to compare data with another.
There are claims that the technology can help people with chronic pain, depression and even improve memory, but more on that later. TDCS it is far from a proven technology. Proving that something like this works in conditions that are highly susceptible to the placebo effect can be challenging, but results are promising and I know of at least 1 start-up attempting clinical trials with this kind of technology.
It will be amazing if this technology is proven to work as there is some evidence that it can improve reaction speed, reading ability and even creativity. I may try to build a simple machine and will share my results on the blog if I do. Of course for those people who are hesitant to use an unproven technology especially when it includes electrically altering your brain there is always Think Gum. As you know, a peer-reviewed study demonstrated that Think Gum improved memory by over 25%. We’ll have to see how TDCS stacks up.