Many people suffering in chronic pain are taking less pain medication for a variety of reasons, and a growing number of them are zapping their skulls with a weak electric current with the hopes of reducing pain.
This so-called “brain hacking” is used to treat neurological and psychiatric symptoms using transcranial direct current stimulation” (tDCS). tDCS is not approved by the U.S. Food and Drug Administration, and scientists are split on its efficacy, with some calling it quackery and bad science.
In Europe, tDCS therapy has regulatory approval for the treatment of fibromyalgia and migraine headache, as NPR reported earlier this year.
Why the split opinion and regulatory status on the therapy? Until now, scientists have been unable to understand what is actually happening in the brain, but that is likely going to change due to new research from the University of Southern California.
Danny JJ Wang, a professor of neurology at the USC Mark and Mary Stevens Neuroimaging and Informatics Institute, said his team is the first to develop an MRI method whereby the magnetic fields induced by tDCS currents can be visualized in living humans. Their results were published Oct. 4 in Scientific Reports, a Nature Publishing Group journal.
“Although this therapy is taking off at the grassroots level and in academia, evidence that tDCS does what is being promised is not conclusive,” said Wang, the study’s senior author.
“Scientists don’t yet understand the mechanisms at work, which prevents the FDA from regulating the therapy. Our study is the first step to experimentally map the tDCS currents in the brain and to provide solid data so researchers can develop science-based treatment,” he added.
“This noninvasive, easy-to-use, low-cost technology has been shown to improve cognition as well as treat clinical symptoms,” said Mayank Jog, study lead author and a graduate student conducting research at the David Geffen School of Medicine at UCLA.
The study is a technological breakthrough, said Maron Bikson, study co-author and a professor of biomedical engineering at The City College of New York.
“You cannot characterize what you cannot see, so this is a pivotal step in the development of tDCS technology,” Bikson said.
The researchers validated their MRI algorithm with a phantom, where the current path and induced magnetic field was known. Then they tested the method using simple biological tissue: a human calf. Finally, they repeated the process on the scalp of 12 healthy volunteers.
After 20 to 30 minutes in a scanner, the new algorithm produced an image of the magnetic field tDCS created. Researchers noted that a current did enter the body and brain. Next, scientists compared the technique with that of a computer simulation.
The phantom test highly matched the computational modeling, thus verifying the algorithm. The brain test showed expected magnetic field changes under and between the electrodes. However, computational modeling was not performed on the brain test because there are too many variables, strengthening the argument that using computational modeling is not ideal for understanding what really happens inside people’s heads when tDCS is applied, Wang said.
“Scientists who have comprehensively studied the tDCS literature are in broad agreement that tDCS can change brain function, but that application in central health and neuro-enhancement will benefit from a deeper understanding of mechanism and enhanced technology,” Bikson said. “This study is an important step in both directions.”