Two developments over the past month signaled the growing popularity of transcranial direct current stimulation, commonly referred to as tDCS, in America. In late July, the U.S. Defense Department announced that Halo Sport would partner with a Pentagon start-up company (Defense Innovation Unit Experimental hyperlink) to use the device to bolster the athleticism of elite American special operations troops, already highly-skilled professional soldiers who train hard to maintain top physical conditioning. “This new approach is already generating lots of enthusiasm,” Secretary of Defense Ash Carter said during an official launch of the partnership. “Our military services, combatant commands, and defense agencies like the speed and agility it affords.” Days later, a handful of American Olympians arrived in Rio for the 2016 games, having used Halo’s electricity-generating headphones to train and prepare for competition. Which begs the question: does it work? “There’s quite a bit of evidence showing that brain stimulation over the motor cortex improves motor performance,” said Anna Wexler, a Ph.D. candidate at the Massachusetts Institute of Technology, who is closely studying tDCS devices, in particular the "do-it-yourself" communities. “Halo is on relatively solid scientific ground.” The company’s CTO and co-founder Brett Wingeier, formerly an engineer and clinical scientist at NeuroPace with 25 patents to his name, explained the process as targeting a specific area of the brain that governs how we move our bodies. “A lot of high physical performance is actually due to your brain optimally controlling your body, and one thing that happens when you train is that your brain constantly itself,” Wingeier said. During a 20-minute session, Halo, he said “…accelerates the neurological improvements with training, so your brain gets a little better a little bit faster at controlling your body.” Research conducted in scientific laboratories backs up that claim. Neuroscience According to Wexler, the study of tDCS really got going around 2001. And the idea of brain stimulation has gone far beyond improving learning and athletic skills to look for answers in treating serious illnesses — epilepsy, Parkinson’s Disease, chronic pain and depression and anxiety. Among the 1,000 peer-reviewed scientific studies now completed, Wexler, who has done a lot of research on devices made at home (direct to consumer) by the so-called “do-it-yourself” (DIY) community, has written there is reason to think the therapy could be beneficial for such conditions. “There’s one side, the direct-to-consumer side, which is a little more iffy. And then there the laboratory studies, which are more controlled, which I am inclined to trust more,” Wexler said. “But there has been a lot of hype about studies with really small sample sizes. DIY video for a homemade tDCS device: Wexler believes it’s doing “something,” pointing out the many great neuroscientists who are working on tDCS. Still, she is cautious. “The reports of benefits may be hyped up at this point, but I think it’s too early to tell,” she said. Regulation One frontier in the world tDCS is regulation. One obvious U.S. organization that would consider such products is the Food and Drug Administration (FDA), which has a somewhat fuzzy ruling on brain-stimulating devices. “The FDA has not cleared or approved any tDCS devices,” said Deborah Kotz, a spokeswoman with the agency. But it will if the device meets the definition of “medical device:” according to Kotz, some examples would be “reducing muscle soreness, shortening injury recovery time or increasing blood circulation.” Which raises the question about those who are using brain stimulation (many of whom exchange tips on how to use or build a device in online communities) to enhance overall brain function or learning or to just feel better overall. As for Halo, it’s not yet on the market. According to Wingmeier, they’ve taken in many pre-orders and plan to open its online shop to all later this year. Because the device is classified non-invasive and not intended to treat disease, the headphones didn't need FDA approval.