For class credit in a psychology course, University of Chicago student Marianne Dolan had her brain zapped with electricity on a Tuesday afternoon in the psychology department at Kelly Hall. It was that or write a paper, she said.
Down the hall, associate professor of psychology and director of the university’s Memory Lab, David Gallo, explained Dolan was part of a study on transcranial direct current stimulation, tDCS. The technique, which directs 1 to 2 milliamps of current to the brain via electrodes secured by a headband, is becoming increasingly popular as an effort to improve brain function.
And Chicago is a microcosm of the world’s discomfort between scientific research and entrepreneurial free thinking on tDCS. While scientists such as Gallo, who is leading one of four tDCS studies here, take a deliberate and skeptical approach, a commercial consumer market and an army of do-it-yourselfers has leaped ahead a few steps.
“We all want to believe,” Gallo said that afternoon. His research is trying to determine if tDCS can be effective in memory retrieval and whether it matters what time of day the electricity is applied. “But scientists have to take it a step further. We have to disassociate ourselves from those beliefs.”
TDCS has produced encouraging, if temporary and anecdotal, results in treating depression, chronic pain, migraines, schizophrenia and the effects of strokes. It also has been linked to improved cognition, processing speed, attention and memory — even reducing smoking and alcohol intake.
But tDCS’ effects have been inconsistent, and some critics suggest, nonexistent. They also are concerned that so many people are using the technique when its long-term impact remains unknown.
About 30 miles north of Kelly Hall, in a bedroom converted to an office, Alex Heredia represents the entrepreneurial wave sweeping tDCS, also known as brain hacking.
For weeks after Heredia fell off his bike and conked his head, he felt foggy and depressed, even though doctors told him his brain looked healthy.
He turned to the internet and found transcranial direct current stimulation. Heredia did more research and, desperate to find a solution, built a device to deliver the milliamps, wired it to his scalp and flipped the switch.
“It brought my life back,” Heredia said one recent morning in his Wilmette home office. The cracked bike helmet that may have saved his life hung from the wall about two feet from a color poster of the brain’s anatomy. “I felt more focused. I felt more energized. I felt like myself again; in some ways, even better.”
Today, almost five years after his spill, Heredia said he uses tDCS three times a week for 20 to 30 minutes a session.
“Wow. Fascinating,” Gallo said when told of Heredia’s experience. “He may well be getting these benefits. But without the objective testing, it’s not quantifiable.”
So ardent is Heredia’s belief in tDCS’ potential that in 2015 he created a company that builds and sells tDCS devices.
It is among about a dozen enterprises that have popped up in recent years, making and selling the devices. Priced from $45 to $410 and beyond, kits generally include a power source, wires, electrodes and headband.
At the same time, at least three Chicago institutions are testing tDCS on stroke patients, people who have suffered traumatic brain injuries and, in Gallo’s lab, undergraduates with healthy brains.
Advocates say tDCS primes the brain, making synapses fire a little better and augmenting the brain’s fundamental learning process. The technology typically is paired with other activity, such as motor skills.
But, uncertainty and skepticism persist, in part because so little is known about the brain.
Where it came from
Electrifying the brain for health reasons has been around for centuries and dates to ancient physicians’ use of the torpedo fish for treating headaches, gout and lower limb pain. Electroconvulsive therapy, ECT, was developed in 1938 and found to be an effective treatment for psychiatric illnesses, especially severe depression and mania.
Many trace the contemporary origins of transcranial direct current stimulation to a 1981 study in Germany that showed subjects who received electrical stimulation to the brain shortened their reaction times. That work was followed by research in 2000 by German doctor Michael Nitsche, who found that tDCS could change brain function for at least several minutes.
“That convinced a lot of people very quickly,” said Vince Clark, director of the Psychology Clinical Neuroscience Center at the University of New Mexico and a leading researcher of tDCS. “People started believing that there must be something real there.”
Other studies followed, including one Clark led in 2012 that showed college students’ ability to identify concealed, “threat-related objects” improved significantly after tDCS.
Today, clinicaltrials.gov, a clearinghouse of publicly and privately funded clinical studies around the world, lists 580 projects on tDCS. Experts say more than 2,000 studies have been written about the technology.
One of the most anticipated clinical trials is running at the University of Florida, where researcher Adam Woods, assistant director of the university’s Center for Cognitive Aging and Memory, is studying tDCS’ impact on older adults’ cognition.
While those studies unfold, Caputron, a leading distributor of tDCS devices and related gear, is experiencing robust growth, CEO Robin Azzam said. The company, based in New York City, sent out about 20,000 tDCS products last year. That figure is double what it distributed in 2015, Azzam said.
“For 2017, we expect to double that,” he said of last year’s distribution numbers, which spike during finals weeks at universities. “We’re just scratching the surface.”
Although Heredia declined to provide raw numbers, he said sales are up since he started TheBrainDriver.com in April 2015.
TDCS also is gaining traction in sport. The U.S. Ski Team, several Olympic athletes, and National Football League players endorse tDCS headphones made by Halo Neuroscience of San Francisco. Published reports also state that several players on the powerhouse Golden State Warriors use the headphones.
Type “diy tdcs” on Youtube and nearly 1,200 results flow to the screen, including about 20 videos explaining how to build a device. Reddit, the social news website and forum, has a tDCS community with more than 9,200 subscribers. That number was 1,300 in October 2012, a Reddit spokeswoman said.
Not so fast
That popularity has created an awkward situation in Chicago and elsewhere.
The FDA has not approved transcranial direct current stimulation. Skeptical scientists trying to determine the technology’s validity generally agree that it shows promise. But tDCS has many variables, including exactly how much electricity to apply, how long to apply it and precisely where on the brain to direct it.
It’s even unclear how much electricity reaches the brain.
“It’s great that it’s available to people,” said Sangeetha Madhavan, director of the Brain Plasticity Lab at the University of Illinois at Chicago and associate professor of physical therapy there. She is in the fourth year of a five-year study on whether applying tDCS to stroke patients for 15 minutes during a motor task followed by walking on a treadmill will help the patients learn faster, retain that motor learning and walk faster.
“But I don’t think we’re at the point where people can start using it on their own,” Madhavan added, “because there is so much unknown about it.”
Among the unknown is why some people respond to tDCS and others do not, Madhavan said, and what the appropriate dosage should be. But she said she still likes that it appears to be much less risky and less expensive than prescription medicine, and is easy to administer.
Critics — notably authors of two meta studies of the research literature — also contend tDCS may have no effect whatsoever. Most experts say the level of electric current is so small that it probably is harmless beyond the tingling that some people feel on their skin where the electrodes are placed. But they also note that exciting one area of the brain typically leads to losing some activity in another.
And, science still understands so little about the complexities of the brain.
“We think it’s helping, but who knows what else it’s doing?” said Leora Cherney, director of the Center for Aphasia Research and Treatment at the Rehabilitation Institute of Chicago. Also a professor of physical medicine and rehabilitation at Northwestern University, Cherney has been studying tDCS’ effect on people dealing with language processing impairment after a stroke, known as aphasia, since about 2011.
“People are buying it and people are doing it to themselves,” she said one morning at RIC, “and they think it makes them feel good. That’s all very well if you’ve got a healthy brain, but now we’re talking about people who’ve had strokes. We have all these questions.”
Cherney will set out to answer some of those questions this month when she leads research looking at the most beneficial time to administer tDCS to aphasia patients — before or during speech and language therapy.
One of her colleagues at RIC and Northwestern, cognitive neuroscientist Jordan Grafman, also is studying tDCS. His work focuses on its impact in stimulating areas of the brain that inhibit inappropriate behavior. Results show it does improve “response inhibition” in healthy volunteers, Grafman wrote in a 2016 article in Brain Stimulation journal.
Now his research is trying to determine if tDCS has the same inhibitive effect on people with traumatic brain injuries.
TDCS “is one tool, but there are many others,” Grafman said in an interview. “It’s a technique to try to modulate brain function. Hopefully the brain takes over in the long run.”
TDCS also can work in unpredictable ways, said Kathleen Hanold, a board certified practitioner of acupuncture and owner of West Meets East Acupuncture, a holistic health practice in Chicago combining western and Chinese medicine. In the last year, she’s used tDCS on two clients to treat depression. The results were mixed, she said.
“It’s another mode or mechanism to deliver treatment,” she said. “I think it’s got potential. We’re going to find all kinds of uses for — if not this device — something like it.”
Marom Bikson is optimistic and pragmatic. A biomedical engineering professor and co-director of Neural Engineering at the City College of New York, Bikson said it is clear that tDCS can change the brain. Many people are unwilling to wait for science to make the same conclusion, he added.
“The people who are incredulous or skeptical, there’s more of this sense that we’re moving too fast,” Bikson said. But people who are suffering from depression, chronic pain and cognitive decline “have a different time scale,” he said. “They don’t have 10 years, and I don’t blame them for looking for alternatives.”
As urgent, popular and intriguing as tDCS is, science continues on its deliberate path, as it did in Gallo’s University of Chicago lab on that Tuesday.
Dolan, the student in the room down the hall from Gallo, finished her tDCS session, took the memory test and was getting ready to leave when she was asked if she felt different after her session.
“I think maybe a little bit,” said Dolan, 20, a psychology major from Portland, Ore. “I do feel slightly more awake now, but that could be many factors.”
It wasn’t the tDCS. Dolan was in the placebo group. Instead of receiving 20 minutes of continuous electricity, she got a burst at the start of her session and nothing more.