Buzz
Using wet sponges and electrodes on your scalp is becoming quite popular. This method, known as transcranial direct current stimulation (tDCS), has been linked to improvements in areas such as learning math, enhancing language abilities, and even boosting workout endurance. However, there is still debate among scientists about whether tDCS truly lives up to its promises.
Some researchers are excited about the potential of tDCS, claiming that it comes with fewer side effects compared to psychiatric drugs. Multiple studies suggest it could enhance our learning capacity in a variety of fields, and there is also evidence that a mild electrical current could help treat several mental health issues.
Clinical studies are currently investigating tDCS as a treatment for various conditions such as depression, chronic pain, insomnia, Parkinson’s disease, schizophrenia, and addiction. A growing community of biohackers and DIY enthusiasts are building their own devices or purchasing kits to experiment with the technology at home.
On the other hand, some experts remain doubtful, questioning whether tDCS is as safe and effective as its proponents claim. Despite positive results in laboratory settings, none of its medical benefits have been approved by the FDA, and recent research challenges the technology’s ability to significantly alter brain activity. Critics point out concerns about small sample sizes, placebo effects, and potential side effects like skin burns.
Jason Forte, a cognitive neuroscientist at the University of Melbourne, expresses concern about the potential hazards of using tDCS at home. He explains, 'If the device isn't used properly, there is a risk of skin damage where the electrode is placed. Although not yet reported, poorly designed devices, if misused, could potentially interfere with heart function.'
Debates like these are typical in academia. Each decade introduces a new drug or device, sparking excitement among researchers and capturing the public's attention. Prior to release, hundreds of studies are conducted to assess safety, the optimal way to use the technology, and its most promising applications.
However, tDCS’s relative safety and ease of construction have allowed it to bypass much of the typical review process and move from laboratories to living rooms. Startups like The Brain Stimulator, TransCranial Technologies, and Halo Neuroscience now offer DIY tDCS devices to eager self-experimenters and patients in need. This shift has raised concerns among some researchers and regulatory experts, while others see no issue with distributing the technology.
Understanding How Brain Stimulation Works
With tDCS, the brain is stimulated using a steady, low electrical current—typically between 1 to 2 milliamps—for a duration of 20 to 30 minutes each day. The sensation felt is often described as tingling or mild stinging at the site of the electrode. Neurons transmit both electrical and chemical signals. Researchers believe that the small electrical current from tDCS makes neurons more likely to fire an electrical signal, thereby triggering the release of neurotransmitters in the brain.
tDCS is just one variant of mild electrical brain stimulation. Other options include transcranial alternating current stimulation (tACS) and cranial electrotherapy stimulation (CES). In tACS, the defining feature is 'alternating.' Unlike tDCS, the current in tACS continuously switches, fluctuating between positive and negative. Scientists believe that tACS doesn’t target individual neurons but instead alters the brain's overall electrical frequency, which can enhance different states such as sleep or concentration.
In CES, a related technology, the current is also pulsed. Fisher Wallace, a company that sells CES devices, asserts that the technology can raise neurochemical levels in the brain, including serotonin, though there’s minimal evidence supporting this claim. Among the three, CES is the only device approved by the FDA for treating depression, anxiety, and insomnia. However, it hit the market before the FDA required proof of efficacy for class III medical devices, meaning it didn’t undergo the same level of scrutiny as devices face today.
tDCS has attracted more attention from researchers than the other forms of brain stimulation, including ongoing clinical trials. This heightened interest has led to a growing number of self-experimenters attempting to replicate these studies.
The Claims of Devices Have Not Been Fully Tested
Michael Oxley was inspired to develop his first brain stimulator after reading a New Scientist article on tDCS in 2012. As a mechanical engineer, he hoped that stimulating his brain with mild shocks would boost his energy and improve his focus. Five years later, Oxley’s company, foc.us, has sold tens of thousands of tDCS headsets, which are marketed as tools to 'enhance alertness, boost focus, and increase learning capacity,' even claiming they can 'help you run further and faster.'
However, Oxley acknowledges that the devices from foc.us have not been subjected to formal external testing or clinical trials. Instead, the company’s claims are based on self-experimentation and the broader scientific body of work.
The FDA permits these claims about cognitive and physical performance because they do not make any medical assertions. However, Anna Wexler, a biomedical ethicist at the University of Pennsylvania, points out that they could still be regulated by the Federal Trade Commission.
"[The FTC has] taken action against several companies making cognitive enhancement claims, both in the supplement industry and the brain training field, showing that they’re willing to intervene," Wexler says. "They haven't yet taken action against any tDCS companies, but in practice, they could."
Oxley emphasizes that he does not market his products for treating psychiatric conditions, not just out of concern for FDA repercussions, but also because he believes it would be irresponsible. Nevertheless, some customers have reported using foc.us’s devices to manage their depression. Wexler’s upcoming research supports this, revealing that a third of users apply the technology for self-medicating mental health issues like depression.
The Potential Benefits of tDCS
Marom Bikson, a professor of biomedical engineering at The City College of New York, states that tDCS alone doesn’t have much impact. Its true potential is realized when paired with learning. He suggests using the technology before or during the process of learning something new, such as playing the piano.
The concept 'neurons that fire together, wire together' captures the essence of how tDCS works. By increasing the chances that a neuron will fire, tDCS aids the brain in forming new connections while learning, a process known as plasticity. This connection to learning is why tDCS is promoted as having numerous potential applications.
"When you apply direct current stimulation, you alter existing plasticity. It doesn’t create new plasticity, but enhances the plasticity already happening," explains Bikson. "The direct current stimulation strengthens that plasticity, making learning more effective."
According to Bikson, the placement of the sponges and electrodes doesn’t matter much in this approach. This is because only the neurons involved in plasticity are affected by tDCS, regardless of where the device is applied.
In contrast, for conditions like anxiety and depression, researchers focus on stimulating a specific area of the brain—the dorsolateral prefrontal cortex—which is less active in people with depression. Regular tDCS stimulation of this area helps restore normal neuron activity, potentially improving mood.
A large-scale study released earlier this year demonstrated that tDCS outperformed a placebo in treating depression. These findings suggest that tDCS may effectively alleviate depression symptoms, though the research also indicated that it is not as potent as conventional medications like SSRIs.
What Could Go Wrong
Even small changes in brain regions, just a few millimeters apart, can lead to vastly different functions. With tDCS, the sponges placed on the scalp span several centimeters, making it hard to ensure precise targeting. Some researchers have raised concerns about the potential for off-target effects, especially when using tDCS to treat psychiatric disorders, which requires stimulation of a specific brain region. The brain functions like prime real estate: it’s all about location. Off-target effects are particularly worrying for those using DIY stimulators without a neuroanatomy background.
"You’re stimulating broad areas of neurons, which then have cascading effects on other neuron groups and networks, so electrode placement is crucial," says Tracy Vannorsdall, a neuropsychologist at Johns Hopkins University School of Medicine. "Even minor variations in the electrode setup—where they are placed on the brain—can lead to significantly different cognitive outcomes."
Studies have shown that boosting one area of the brain’s function can sometimes impair another area. While less dramatic, another concern is the reports of home users experiencing burns or skin damage where the electrodes are placed.
Another concern is that the method may not have any effect at all. Numerous studies have reported no noticeable impact, either in behavior or brain activity, when using tDCS. In one of the most distinctive tests of the technology, scientists found that only 10 percent of the electrical current was able to penetrate the skull of a cadaver to reach the brain. This suggests that tDCS has much less influence on the brain than researchers initially anticipated, potentially not enough to produce any significant changes in neuronal behavior.
So, Should You Do It?
If you’re considering giving it a try yourself, instead of spending hundreds of dollars on a device, neuropsychologist Vannorsdall suggests participating in one of the 700 tDCS clinical trials listed on clinicaltrials.gov, which accept both patients and healthy individuals. “I believe it’s still too early for people to experiment on themselves,” she advises.
However, Bikson, a biomedical engineer, believes self-experimentation might not be as problematic as some think. Five years ago, his initial response as an academic researcher was to treat it like his exclusive domain, but he’s since softened his stance. “I’m really hesitant to discourage someone who’s suffering or whose loved one is in distress,” he says. “While I’m not endorsing it, I’m also not condemning them. Many of us in the clinical and research fields believe these technologies could be effective.”
