Adam Kirton, a pediatric neurologist in Calgary, Alberta, has seen first-hand the devastating effects that strokes can have on a child’s brain. Lifelong paralysis and a form of cerebral palsy can result, and treatment options are few.
This is why Dr. Kirton is exploring an as yet unregulated but potentially promising therapy for children with neurological impairment: transcranial direct current stimulation, or TDCS.
Simple in design, TDCS places electrodes affixed to kitchen sponges against a person’s head. A power supply then sends weak electrical currents through the skull to stimulate the brain.
Though scientists say the therapy needs more testing before its effectiveness is established conclusively, TDCS is based on a simple neuroscientific axiom: Neurons that fire together wire together. And strengthening certain connections could help a child with neurological impairment perform even the most simple tasks.
TDCS, which isn’t regulated by the Food and Drug Administration, has been used on adult stroke victims with promising results. Indeed, a few studies have shown it to help in alleviating such stroke-related symptoms as the inability to speak. A slew of randomized control studies also have shown TDCS can work to treat adult depression.
Over the past five years, scientists have taken an increasing interest in researching TDCS for neurological impairment in children, who have more malleable, and thus possibly treatable, brains. The hope is that TDCS may someday be proven effective in the treatment of such severe childhood conditions as cerebral palsy and epilepsy. So far the therapy’s effectiveness has been studied less in children than in adults, but researchers say there are some initial positive signs. The therapy has been tested in several trials involving children who have experienced stroke, where results have also been encouraging.
A growing body of scientific literature suggests TDCS is safe for children. Researchers at the Hospital of the University of Munich in a review paper published in the Journal of Neural Transmission in October found that while the therapy can cause headaches and itchiness, it is generally well tolerated by children and adolescents with a range of medical conditions.
A clinical trial conducted recently by a team led by Dr. Kirton also suggests TDCS is safe for children, at least in the short term. In the trial, involving 24 children and adolescents at Alberta Children’s Hospital, weak electrical currents were directed near the section of the brain responsible for motor control.
“We’re not warping their brains or inducing different functions,” Dr. Kirton says. “The idea is to try to enhance the brain’s natural ability to change.”
The results of Dr. Kirton’s trial, published recently in the medical journal Neurology, suggest possible benefits from TDCS but also a need for further study. Dr. Kirton plans to begin a new trial on 80 children this summer.
A question of dose
Many doctors, including Dr. Kirton, see a slew of ethical and practical questions that must still be answered, such as how to dose and whether stimulation has long-term effects on still-developing brains. Children’s skulls are thinner, and their brains have a different composition of white matter versus gray matter than a mature adult’s brain, which is important since the flow of current varies across different types of tissues.
“With medication there are clear pathways to determine which dose to give,” says Sudha Kessler, a pediatric neurologist on the staff of Children’s Hospital of Philadelphia. “Brain stimulation is a whole different thing.”
Dr. Kessler works with children who have epilepsy, a brain disorder that’s characterized by frequent seizures. She initially took an interest in TDCS because she wondered if the excitability that happens in a child’s brain during a seizure could be balanced, or fixed in some way, by TDCS currents.
To help researchers like herself, Dr. Kessler designed a study in 2013 aimed at determining the correct TDCS doses for children. Based on a detailed analysis of children’s brain layers and tissues as well as their skull thicknesses, she used MRI data to create a digital model of a child’s brain. Then she used electrical conductivity modeling—based on the individual properties of each simulated brain layer—to estimate the effects of various levels of stimulation. She found that head size and age do indeed determine sensitivity to the therapy and should guide doctors in deciding on what dosage of electricity to apply.
“There is just a very initial first step,” Dr. Kessler says. And because TDCS research is in its infancy, she adds, studies such as hers don’t account for another dilemma: the potential long-term consequences of applying electrical currents to brains that are still developing.
An ethical puzzle
Caroline Ketcham was dubious when she first heard about the promise of a new technology for children like her son, who, at the time, hardly spoke.
Ms. Ketcham is a motor neuroscientist at Elon University in Elon, N.C., and the mother of a child with autism, apraxia and attention-deficit hyperactivity disorder. Five years ago, she says, she heard a clinician speak about TDCS.
It sounded like “voodoo medicine,” she says.
But Ms. Ketcham looked at the research and eventually decided it was safe and worth a try. She enlisted the service of Harry Schneider, one of few doctors nationwide who uses TDCS therapy on children. Dr. Schneider has clinics in New York City and China Grove, N.C., where he uses TDCS to treat verbal disorders and symptoms associated with autism, among other disorders.
After just a few visits with Dr. Schneider, who also provides a suite of other verbal therapies, Ms. Ketcham’s young son began tracing his letters at school. On Ms. Ketcham’s birthday that first year, she said her son told her, “I love you.”
“That was probably the first conversation I had with him,” she says. “I wouldn’t say TDCS is magical, but you get these glimpses of progress that just continue forward.”
Ms. Ketcham’s son uses TDCS every few months. She pays about $740 for six hours of treatment with Dr. Schneider. Her insurance covers parts of the care, but not the TDCS treatment itself.
Dr. Schneider says he was regarded with skepticism when he started using TDCS on patients in 2004. The parents of his patients, however, have exhausted conventional treatment options, he says. He estimates he has used TDCS on some 2,000 patients from the ages of 4 to 31.
“I believe patients try TDCS because they are frustrated with years of doing some form of therapy without a positive outcome,” says Dr. Schneider, who adds that his practice using TDCS and his thorough research of the medical and scientific studies on the topic have led him to conclude that it is safe for clinical use.
“ ‘First, do no harm’ is the oath I actually took when I was graduated from medical school,” Dr. Schneider says. “I am using TDCS because scholar after scholar, scientist after scientist, have confirmed that TDCS is safe.”
Roi Cohen Kadosh, a professor of cognitive neuroscience at the University of Oxford in Britain, published a paper in 2012 about the ethics of using TDCS on children and concluded that while it seems safe, ethical issues such as long-term impacts and use without a specific therapy regimen should be taken seriously. “There is no evidence that can tell us, ‘Look, it can be used in clinics in order to improve X, Y and Z,’ ” he says.
Drs. Kirton and Kessler agree that so far there isn’t enough scientifically based evidence to support clinical use of TDCS. However, both doctors still think that the therapy warrants further research.
“As a neurologist,” Dr. Kessler says, “I would not offer any therapy to families unless I thought there was enough information that indicated the benefits of such therapy outweighs the risk, no matter how desperate the situation is.”
Ms. Furfaro is a writer in New York City. She can be reached at firstname.lastname@example.org.