Thync’s strategy is to bypass the brain and instead use pulsed currents to stimulate peripheral nerves closer to the surface of the skin, with the goal of modulating the user’s stress response.
“We spent a year and a half optimizing the wave forms to the point that we felt really confident in the science,” said Jamie Tyler, the company’s chief science officer. His team has tested about 3,300 people in single-blind and double-blind, placebo-controlled studies.
Wave forms refer to a series of electric pulses that change frequency and amplitude over time. Like a sound equalizer, the theory goes, the parameters can be “tuned” to produce an intended biological effect.
Soon into my 20-minute demonstration, I feel a sharp, slightly painful tingling above my eye, like vibrating pinpricks. I brace myself, awaiting relaxation.
According to Dr. Tyler, the “calm vibe” at its peak produces a relaxation greater than that provided by three Benadryls, according to a common statistical measure for effect size. The “energy vibe” is said to be stronger than that produced by a 20-ounce can of Red Bull. Each mood lasts for about 45 minutes without a subsequent crash, Thync says.
But some experts are skeptical, insisting that the company show evidence of peer-reviewed, independently replicated results.
Very well researched and well-balanced article from Mark Harris at The Economist.
Hardly surprising, then, that DIY brain hackers want in on the action. Christopher Zobrist, a 36-year-old entrepreneur based in Vietnam, is one of them. With little vision he has been registered as blind since birth due to an hereditary condition of his optic nerve that has no established medical treatment. Mr Zobrist read a study of a different kind of transcranial stimulation (using alternating current) that had helped some glaucoma patients in Germany recover part of their vision. Despite neither the condition nor the treatment matching his own situation, Mr Zobrist decided to try tDCS in combination with a visual training app on his tablet computer. He quickly noticed improvements in his distance vision and perception of contrast. “After six months, I can see oncoming traffic two to three times farther away than before, which is very helpful when crossing busy streets,” he says.
Equally troublesome is a meta-analysis of the cognitive and behavioural effects on healthy adults that Mr Horvath subsequently carried out. As before, he included only the most reliable studies: those with a sham control group and replicated by other researchers. It left 200 studies claiming to have discovered beneficial effects on over 100 activities such as problem solving, learning, mental arithmetic, working memory and motor tasks. After his meta-analysis, however, tDCS was found to have had no significant effect on any of them.
If tDCS alters neither the physiology of the brain nor how it performs, thinks Mr Horvath, then evidence suggests it is not doing anything at all. Marom Bikson, a professor of biomedical engineering at City University of New York, disagrees. “I can literally make you fall on your butt using the ‘wrong’ type of tDCS,” he says. Dr Bikson thinks the biggest challenge for tDCS is optimising techniques, such as the dose.
Zap goes the effect
The team pooled the results of more than 400 studies that reported a change in cognitive skills following a session of tDCS.
“Most studies have more than one outcome measure, such as accuracy, speed, errors made and so on,” explains Horvath. And while one study may show, for example, improved accuracy on a memory task after tDCS but no effect on speed or errors, another memory study may show improved speed, with no effect on accuracy or errors. When put together they cancel each other out. This pattern played out in studies of memory, processing speed and mathematical ability, Horvath found.
Roi Cohen Kadosh, a neuroscientist at the University of Oxford who has studied the effects of tDCS on mental arithmetic, is far from convinced by this argument. “My feeling is that it is very premature to do what they did,” he says. “They did have a large sample size, but they fractured it so that they are comparing the results of three or four studies and expecting to see something meaningful. It’s the easiest thing in science to not find results,” he says.
They found that participants with high maths anxiety made correct responses more quickly and, after the test, showed lower levels of cortisol, an indicator of stress. On the other hand, individuals with low maths anxiety performed worse after tDCS.
“It is hard to believe that all people would benefit similarly [from] brain stimulation,” says Cohen Kadosh. He says that further research could shed light on how to optimise the technology and help to discover who is most likely to benefit from stimulation.
via Personality affects maths-enhancing brain-zap method – life – 09 December 2014 – New Scientist.
Link to full paper: Cognitive Enhancement or Cognitive Cost: Trait-Specific Outcomes of Brain Stimulation in the Case of Mathematics Anxiety