It’s been just over three days since my last cup of coffee. To replace this stimulus, a low, steady hum of electric current is being delivered across my forehead and down through the bone behind my right ear by means of a small, white, plastic triangle affixed just above my right eyebrow. Though initially uncomfortable, like the numb tingling of a jarred funny bone, the sensation quickly subsides to the kind of mild vibration that comes from resting your head against a train window. The effect of this current, according to Thync, the startup based in Los Gatos, California, which produces the $199 device, is to raise or lower your energy levels, with the aim of reducing dependence not only on caffeine but also on various other forms of pharmaceutical mood control, including sleeping pills, alcohol, and even anti-anxiety medication.
It’s hard to gauge its effectiveness. Sometimes the energy settings did seem to induce more focus; and several times on calm mode I fell asleep with the device still attached – though that may have been because of caffeine withdrawal.
Still, Thync is not alone in making these kind of claims. A recent revival of scientific interest in non-invasive neurostimulation methods – particularly transcranial direct current stimulation (tDCS) – has seen a proliferation of studies of varying credibility, purporting to show that a few milliamps can improve not only mood, but also the performance of a range of people, from Parkinson’s-impaired dancers to snipers.
Since they simply involve delivering low currents across the skull, tDCS devices cost mere tens of dollars to produce – so lots of companies are having a go. In addition to Thync, there’s San Francisco-based Halo Neuroscience, which claims that their $749 headphones can improve sporting performance, alongside an assortment of more cheaply constructed and marketed solutions. Amateur tDCS is also as easy as it is inadvisable, requiring little more than a nine-volt battery, electrode leads and easily available circuit components. A discussion on Reddit, an online forum, dedicated to the practice has accumulated over 8,500 members whose most popular topic of conversation is how to avoid electrical burns.
The idea of harnessing the power of electricity to become smarter, stronger or less stressed has a long history. In the popular imagination, it’s best known through the 200-year-old method of electroconvulsive therapy: the use of currents of around 800 milliamps to shock the body into a seizure when treating cases of extreme depression or psychosis.
Scientific backing for commercial manufacturers’ claims of everyday performance and mood enhancement is, however, relatively scant. The strongest piece of evidence came from the first ever peer-reviewed trial of a commercial neurostimulation device. In a study published in Scientific Reports, a journal, 20 intrepid volunteers were shown a slideshow and given a painful electrical shock whenever the image of a lightning bolt appeared. Half the participants, equipped with an identical placebo headset, responded with the classical biomarkers of stress, but those using a genuine Thync unit were measurably calmer throughout.
While the size of this study compares unfavourably to those run in cardiology (where typical participant numbers run to several thousand patients), the science behind it, points out Felipe Fregni, the director of Harvard Medical School’s Spaulding Neuromodulation Centre, is theoretically sound. The brain is an electrical system and the delivery of an electrical current can increase the likelihood of a neuron firing. Neurons thus stimulated are more likely to fire again and more likely to fire together – a natural phenomenon known as neuroplasticity through which the brain learns to associate experiences that regularly occur concurrently, such as the sight of a fountain and the sound of running water, by strengthening the connections between the corresponding neural groups. The question of efficacy hangs on whether a particular device actually delivers enough current, to the right places, in order to produce the claimed effect.
Rather than target neurons directly, Thync stimulates nerves on the face and neck to feed current indirectly into the sympathetic system, known to control the fight-or-flight response, and the parasympathetic system, which regulates our rest-and-digest state. Halo Sport, on the other hand, uses a traditional tDCS configuration, through a headphone-style band that targets the primary motor cortex to improve the co-ordination of signals to the musculature, and so increase the number of muscle fibres activated simultaneously.
Since it was founded in 2013, Halo has raised $10.7m in venture capital, and claims five Olympic athletes, several NFL players, and three Major League Baseball teams among its customers. “I’ve been an athlete long enough to know when I have more strength and power,” claims Hafsatu Kamara, one of the five Olympians, who competed in the 100 metres for Sierra Leone at the 2016 Olympics. “During resistance training I usually do weighted hip thrusts at 100kg – after using Halo I can train at 120kg.”
Six years ago these athletes might have been wearing Power Bands: plastic bracelets embedded with holograms that claimed, with little justification, “to maximise the body’s natural energy flow”. The high stakes and thin margins of elite sport leave athletes extremely susceptible to pseudoscience, so Brett Wingeier, Halo’s co-founder and CTO, knows he needs not only endorsements, but numbers. “One of our best success stories was a placebo-controlled, double-blind study with ski jumpers from the us National Ski and Snowboard Association,” he says. This found that the group wearing Halo Sport developed a smoother jump 80% faster and increased their jumping force 70% more than the group using just a placebo.
Halo’s studies have yet to appear in peer-reviewed journals, and once again the trial size was small with just seven participants. Wingeier argues that most of their efforts are dedicated to reproducing the results of earlier research into tDCS. Thync, meanwhile, can point to its device’s 10,000 users – largely curious early-adopters and sufferers of anxiety, insomnia or migraine, who are willing to give any potential remedy a shot – as evidence of its usefulness. They are launching Thync Relax, a new version of the device, in early April, which will be affixed to the neck alone. While most online reviewers of the original product are enthusiastic, some aren’t. Isy Goldwasser, the company’s CEO, says this variance is a result of incorrect usage, but Fregni is not so sure: “These kinds of neurostimulation can have positive effects, but they are not a 100% solution for anyone.” But the downsides do not seem huge either: apart from a “bit of skin irritation, there aren’t really any major safety concerns.”