NeurostimulationHacking your brain
With a=20 DIY bundle of electronics or a ready-made device it is possible to = stimulate the=20 brain. But does it work and is it safe?
=E2=80=9CIT=E2=80=99S like coffee times = ten,=E2=80=9D raves one enthusiast. =E2=80=9CI use=20 it a couple of times a week and problems solve themselves. At the end of = the=20 day, I haven=E2=80=99t wasted hours on frivolous websites. At the end of = the week, my=20 apartment is clean.=E2=80=9D This marvel of productivity is not a new = energy drink or an=20 experimental wonder drug but a simple electrical device that he built at = home=20 for less than $10. Whenever this physicist feels like an extra burst of=20 motivation, he places electrodes on his skull and sends a jolt of = electricity=20 into his brain.
The currents, which are typically applied for = ten to 20=20 minutes, are hundreds of times smaller than the seizure-inducing shocks = used in=20 electroconvulsive therapy. Plans to make such transcranial direction = current=20 stimulation (tDCS) machines are freely available online and their = components can=20 be bought at hobbyist stores. Kits cater to those lacking soldering = skills, and=20 now companies are emerging offering nicely designed and packaged brain = zappers=20 for mainstream consumers.
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Not everyone using tDCS is seeking to become = more=20 efficient in their daily life. Some hope to enhance their concentration = for=20 study or video gaming; others want to boost their memory, speed up = learning or=20 induce meditative calm. Yet more are trying to self-medicate for = conditions such=20 as depression, chronic pain and motor, sensory or neurological = disorders. The=20 benefits might sound implausible, but there is some science to support = them. The=20 idea goes back a long way. Scribonius Largus, a first-century Roman = physician,=20 prescribed the shock of an electric ray for headaches, and in the 19th = century=20 electrical pioneers such as Luigi Galvani and Alessandro Volta toyed = with crude=20 bioelectric experiments. It was not until the 1960s, however, that the = first=20 rigorous studies of electrical brain stimulation took place.
Directing the flow
The theory behind tDCS is that a weak direct = current=20 alters the electric potential of nerve membranes within the brain. = Depending on=20 the direction of the current, it is said to make it easier or more = difficult for=20 neurons in a brain circuit to fire. Position the electrodes correctly = and choose=20 the right current, so the idea goes, and you can boost or suppress all = kinds of=20 things. Some researchers have reported that tDCS can reduce pain, ease=20 depression, treat autism and Parkinson=E2=80=99s disease, control = cravings for alcohol=20 and drugs, repair stroke damage, and accelerate recovery from brain = injuries, to=20 say nothing of improving memory, reasoning and fluency. Remarkably, some = effects=20 seem to persist for days or even months. And the closer that scientists = look at=20 tDCS, the more they seem to find. Scientific papers about the technology = appear=20 at an ever-faster rate.
Hardly surprising, then, that DIY brain hackers = want in on=20 the action. Christopher Zobrist, a 36-year-old entrepreneur based in = Vietnam, is=20 one of them. With little vision he has been registered as blind since = birth due=20 to an hereditary condition of his optic nerve that has no established = medical=20 treatment. Mr Zobrist read a study of a different kind of transcranial=20 stimulation (using alternating current) that had helped some glaucoma = patients=20 in Germany recover part of their vision. Despite neither the condition = nor the=20 treatment matching his own situation, Mr Zobrist decided to try tDCS in=20 combination with a visual training app on his tablet computer. He = quickly=20 noticed improvements in his distance vision and perception of contrast. = =E2=80=9CAfter=20 six months, I can see oncoming traffic two to three times farther away = than=20 before, which is very helpful when crossing busy streets,=E2=80=9D he = says.
Online communities dedicated to tDCS are full of = similar=20 stories. More still claim to have gained cognitive enhancements that = give them=20 an edge at work or play. Users follow the latest scientific papers = avidly and=20 attempt to replicate the results at home, discussing the merits of = different=20 currents, waveforms and =E2=80=9Cmontages=E2=80=9D (arrangements of the = electrodes on the=20 skull).
Dissenting voices are rare. Here and there are = tales of=20 people who experienced headaches, nausea, confusion or sleeplessness = after tDCS,=20 while temporary visual effects and mild skin burns are fairly common. = There have=20 been no reports of seizures, serious injuries or deaths. But that does = not mean=20 it is without risk, says Peter Reiner, co-founder of the National Core = for=20 Neuroethics at the University of British Columbia. He says DIY users may = place=20 electrodes incorrectly, thus stimulating the wrong part of their brain, = or=20 reverse the polarity of current, potentially impairing the very things = they are=20 trying to improve. No one really knows how tDCS interacts with chemical=20 stimulants or recreational drugs like marijuana, or with pre-existing = conditions=20 like epilepsy. Even something as fundamental as being left-handed can = alter the=20 functional organisation of the brain. And if the benefits of tDCS can = persist=20 for weeks, perhaps its side-effects can linger, too. Many = neuroscientists are=20 particularly worried that the use of tDCS by children and young adults = could=20 affect their long-term neural development.
Some of these concerns can be addressed by = manufacturing=20 tDCS devices to make it difficult, or impossible, to exceed recommended = currents=20 or to apply the electrodes incorrectly. One such product already exists. = The=20 Foc.us V2, made by Transcranial, a London company, is advertised as a = $199=20 pocket-sized controller that pairs with a $99 headset intended to help = with=20 concentration and reaction speed while videogaming. Donning the headset=20 automatically positions the electrodes on the left and right temples, = and both=20 the duration and maximum current are capped. A second headset provides a = different montage aimed at improving performance and motivation while=20 exercising.
In reality, however, there is no guarantee that = even slick=20 products are any safer than a pocket-money brain stimulator assembled at = home=20 from a 9-volt battery, electrodes, a few wires and other components. = Unlike the=20 tDCS machines used for medical trials and clinical research, consumer = versions=20 may not have been assessed by any official body for safety or = effectiveness. If=20 the maker insists they are for use only by healthy adults to enhance = cognition=20 or leisure activities and make no diagnostic or therapeutic claims, such = =E2=80=9Cwellness=E2=80=9D devices have slipped under the regulatory = radar of both the Medical=20 Devices Directive in Europe and the Food and Drug Administration (FDA) = in=20 America.
That worries some experts. A recent paper from = the=20 Institute for Science and Ethics at the University of Oxford points out = that=20 consumer tDCS products are mechanically and functionally equivalent to = medical=20 neurostimulation devices that require licensing. Why regulate the = version that=20 is likely to be operated responsibly by health professionals, and not = the one=20 freely available to unskilled and inexperienced users? The Nuffield = Council on=20 Bioethics agrees, recommending in 2013 that the European Commission = should=20 consider regulating all such gadgets under its medical devices regime,=20 regardless of the purposes for which they are marketed.
The Institute for Science and Ethics proposes a = graded=20 regulation system that errs on the side of consumer choice for tDCS = devices,=20 requiring comprehensive, objective information about risks and benefits = to allow=20 users to make informed decisions. But it wants supplying brain zappers = to=20 children to be made illegal. Last year the FDA allowed transcutaneous = electrical=20 nerve stimulator (TENS) machines for headache relief as it rated them as = low-to=20 moderate-risk devices. TENS devices use a different waveform to tDCS and = target=20 cranial nerves rather than the brain itself, but they rely on a similar=20 controller and head-mounted electrodes. Before allowing new TENS = products to be=20 sold, the FDA now wants to see evidence that the components are not = likely to=20 cause injury, that the controller can reliably provide the correct = output, that=20 there are no thermal or mechanical hazards, and that clinical data = demonstrate=20 the device is safe and effective as a headache treatment. Recent draft = FDA=20 guidelines for wellness devices suggest tDCS machines may eventually be=20 regulated in a similar way.
Going underground
The University of British Columbia=E2=80=99s Dr = Reiner doubts that=20 any manufacturer today can provide such information for tDCS. Even if = they=20 could, the cost of gathering it would make consumer devices more = expensive.=20 =E2=80=9CWhen you can make a tDCS device yourself for less than $20, we = would advise=20 strongly against heavy regulation because it will only drive the = technology=20 underground,=E2=80=9D he says.
Proving the effectiveness of brain stimulation = will be=20 difficult. Although it may well do something, exactly what is open to = question.=20 As the hype around tDCS grows, some neuroscientists are starting to = question=20 whether the technology really is the panacea it appears to = be.
In 2013 Teresa Iuculano and Roi Cohen Kadosh of = the=20 Department of Experimental Psychology at the University of Oxford split=20 volunteers up into three groups and asked them to learn a made-up = mathematical=20 notation system. The first two groups received tDCS to different parts = of the=20 brain previously associated with numerical understanding and learning, = while a=20 non-functional =E2=80=9Csham=E2=80=9D device was used on the third group = as a control. After a=20 week, all three groups were tested on how well they had learned the new = notation=20 system, and whether they could use it in practice. The first group = showed an=20 improvement in learning compared with the control group, but a decrease = in their=20 ability to apply their knowledge, while the second group experienced the = opposite result. This suggests that the brain is actually rather well = balanced:=20 boost performance in one cognitive realm through stimulation, and = aptitude in=20 another will naturally diminish.
There is also the possibility that a variation = in=20 individual responses to tDCS will overshadow any general effects. In a = study=20 published last year, Dr Cohen Kadosh set up two groups: one of people = who were=20 anxious when presented with mathematical problems, and another who had=20 confidence in their ability to breeze through numerical quizzes. When = treated=20 with tDCS to their prefrontal cortices, the nervous individuals improved = their=20 reaction time on simple arithmetical problems and showed reduced levels = of=20 stress. Given the same treatment, the confident group had longer = reaction times=20 and no less stress. =E2=80=9CIf you can get exactly the opposite results = with a=20 different population, that shows DIY brain hackers and companies = marketing=20 stimulation to improve gaming or other abilities are not on the right = track,=E2=80=9D=20 says Dr Cohen Kadosh. =E2=80=9CWe need to understand how the brain works = in different=20 people.=E2=80=9D
Felipe Fregni, director of the Laboratory of=20 Neuromodulation at Harvard Medical School, says tDCS has been shown to=20 accelerate the learning of new skills. But he agrees that individual = variation=20 is important, noting that younger people sometimes do not improve as = much as=20 older subjects, and that people at later stages of learning may even = experience=20 detrimental effects. =E2=80=9CThe more science you know, the more = confused you can=20 become of what really is the effect of tDCS,=E2=80=9D says Dr = Fregni.
One advantage of the deluge of scientific papers = is that=20 they can be subjected to meta-analysis, whereby studies can be = statistically=20 combined to tease out new discoveries. Last year, Jared Horvath, a=20 neuroscientist at the University of Melbourne in Australia, published a=20 meta-analysis of 30 measurements taken during tDCS studies, including = neural=20 responses, oxygen levels and electrical activity in the brain. = Surprisingly, he=20 found that tDCS had a reliable effect on only one: the electrical = response of=20 muscles to stimulus, and even that has steadily declined in studies over = the=20 last 14 years. Mr Horvath believes this indicates that the response has=20 historically been measured poorly and that it too will eventually = disappear as=20 techniques mature.
Equally troublesome is a meta-analysis of the = cognitive=20 and behavioural effects on healthy adults that Mr Horvath subsequently = carried=20 out. As before, he included only the most reliable studies: those with a = sham=20 control group and replicated by other researchers. It left 200 studies = claiming=20 to have discovered beneficial effects on over 100 activities such as = problem=20 solving, learning, mental arithmetic, working memory and motor tasks. = After his=20 meta-analysis, however, tDCS was found to have had no significant effect = on any=20 of them.
If tDCS alters neither the physiology of the = brain nor how=20 it performs, thinks Mr Horvath, then evidence suggests it is not doing = anything=20 at all. Marom Bikson, a professor of biomedical engineering at City = University=20 of New York, disagrees. =E2=80=9CI can literally make you fall on your = butt using the=20 =E2=80=98wrong=E2=80=99 type of tDCS,=E2=80=9D he says. Dr Bikson thinks = the biggest challenge for tDCS=20 is optimising techniques, such as the dose.
Mr Horvath notes that many papers measure 20 or = more=20 outcomes, with brain stimulation showing a weak effect on one or two. = =E2=80=9CBut in=20 the title and abstract, that=E2=80=99s all they talk about,=E2=80=9D he = says. =E2=80=9CNo one mentions=20 the tons of effects that tDCS didn=E2=80=99t have an impact on but that = technically it=20 should have if it is doing what the researcher thinks it = is.=E2=80=9D
Another problem might be the small sample size, = sometimes=20 as few as ten or 15 people. Mr Horvath says future studies should use at = least=20 150 subjects. There is, of course, the possibility that Mr = Horvath=E2=80=99s analyses=20 are flawed. His paper included only one-off sessions, while many = scientists=20 believe the effects of tDCS accumulate with repetition. However, too few = multiple-session studies exist for a valid meta-analysis. Dr Cohen = Kadosh points=20 out that individual variations could make the technology look as though = it is=20 doing nothing when in fact it has real but opposing effects in different = people.=20 Mr Horvath insists that his analysis allows for this possibility.
Critics might also wonder why Mr Horvath omitted = tests=20 where tDCS seems to have been most effective, in alleviating, for = instance,=20 clinical conditions such as depression. He admits that would be useful = but says,=20 =E2=80=9CIf something doesn=E2=80=99t demonstrate any type of effect in = healthy people, it=20 becomes incredibly difficult, if not impossible, to argue why it would = work=20 within a clinical population.=E2=80=9D
Not all neuroscientists are defending the status = quo. =E2=80=9CI=E2=80=99m=20 not surprised that he found no effect from conventionally applied = tDCS,=E2=80=9D says=20 Jamie Tyler, a professor at Arizona State University and one of the = founders of=20 Thync, a Silicon Valley startup that recently unveiled a = smartphone-controlled=20 tDCS device. Thync tried to replicate some basic tDCS findings on = cognition but=20 could not do so. Dr Tyler now believes that tDCS may not directly = stimulate the=20 brain at all but instead modulates cranial nerves in the skull, like the = headache-busting TENS technology. He designed the Thync device, a = pocket-sized=20 unit with disposable pre-shaped electrodes, to target these nerves with = the aim=20 of generating either relaxed or energetic mental states.
A shot of caffeine
Dr Tyler recently published a study of 82 people = with a=20 control. Its results suggest that Thync=E2=80=99s device can reduce = psychophysiological=20 stress by altering skin conductivity (a measure used in pseudoscientific = lie=20 detectors), stress enzymes and heart rate variability. He likens = Thync=E2=80=99s=20 =E2=80=9Cmodified tDCS=E2=80=9D programs to ingesting either a third of = a cup of coffee or a=20 glass of wine, and says no effect has been found on cognitive processes = like=20 working memory. While Thync=E2=80=99s stimulator is not yet available to = the public, the=20 firm was willing to give your correspondent a pre-launch trial.
The Thync device attaches with one sticky = electrode on the=20 right temple and one behind the right ear. The unit is controlled via a=20 smartphone app, with the user able to adjust the intensity but not the = duration=20 of the session. At first, the unit generated a barely perceptible = crawling=20 feeling on the skin near the electrodes, building gradually to a = pronounced=20 tingling sensation. Over the 20-minute session, the strength of the = signal=20 varied up and down according to a preset routine. It felt itchy at times = and, at=20 its most powerful, caused muscles in the forehead to spasm alarmingly. = Although=20 the experience was not altogether unpleasant, any extra energy or focus = proved,=20 alas, elusive. Dr Tyler acknowledged that perhaps one in four people do = not=20 perceive any immediate benefit from the device.
Even for those who find themselves susceptible = to its=20 charms, the challenges for a product like Thync are formidable. The = cognitive=20 enhancements of a strong cup of tea or a glass of vintage Burgundy are = well=20 established. And partaking of them can be socially acceptable, = deliciously=20 enjoyable and rapidly achieved. None of these can be said of a = disconcerting=20 gizmo that needs half an hour to work and causes eyebrows to raise, both = literally and socially.
Regardless of their questionable utility and=20 effectiveness, tDCS gadgets are too novel, cheap and alluring to simply = dismiss.=20 Consumer-wellness devices like Thync may appeal to those who cannot use = caffeine=20 or alcohol for medical or religious reasons, and there will always be = healthy=20 overachievers seeking to supercharge their cognition for study or work. = More=20 importantly, tDCS presents the tantalising promise of relief from some = medical=20 conditions for which traditional therapies are either ineffective or=20 unaffordable. As the University of Melbourne=E2=80=99s Mr Horvath says, = =E2=80=9CIf there are=20 ten percent of people who are feeling a huge effect, even if = that=E2=80=99s placebo, who=20 are we to say no to them?=E2=80=9D
If people want to experiment with tDCS, there = seems to be=20 no reason to prevent them, provided it is done in the safest way = possible.=20 Devices could be regulated lightly with a view to safety rather than=20 effectiveness, and neuroscientists encouraged to design future studies = with more=20 rigour. Happiness and health may always be more than just a 9-volt = battery away,=20 but brain hacking looks like it is here to stay.