Ask Doctor K: Value of direct current stimulation to brain still unproven
DEAR DOCTOR K: I saw an ad for something called a “tDCS brain-stimulating device.” It supposedly helps improve memory and thinking. Is it worth a try?
DEAR READER: Transcranial direct current stimulation (tDCS) transmits a current into the brain through electrodes (little metal plates) on the forehead or scalp. The current is weak; it comes from a 9-volt battery (the size used in a smoke detector). People who undergo tDCS may feel their scalp tingle and hear a humming noise. Doctors can control whether the current activates – or suppresses – the neurons in your brain that lie beneath the electrodes.
The technique of tDCS has been tried on and off for more than 100 years. The technique is different from another increasingly used technique called transcranial magnetic stimulation.
I spoke to Dr. Daniel Press, a neurologist with the Berenson-Allen Center for Noninvasive Brain Stimulation at Harvard-affiliated Beth Israel Deaconess Medical Center. He says that brain stimulation, if used carefully, looks promising. That’s especially true if combined with other therapies. Several studies are underway to see if, and how, tDCS can be used to sharpen mental skills and treat symptoms of mind-body disorders.
For now, tDCS is only FDA-approved to speed the absorption of certain medications through the skin. But it is being used “off label” to treat many other conditions. These include:
- CHRONIC PAIN: tDCS may be effective for treating nerve pain. This includes back and leg pain, pain and numbness in hands and feet caused by diabetes, and fibromyalgia.
- DAMAGE FROM STROKE: Early research suggests that tDCS may improve a person’s ability to move and speak and to overcome spatial neglect. That is the inability to notice or recognize objects on one side of the body.
- EATING DISORDERS: In early studies, tDCS has reduced episodes of binge eating and bulimia in women with those eating disorders.
- MEMORY AND LEARNING: Many recent studies have evaluated the effect of tDCS on people’s ability to perform mental tasks. Studies have focused on tasks that involve recognizing visual patterns, recalling lists of unrelated words or doing math problems. Overall, the results indicate the technique is most likely to improve mental function when used together with other types of training, such as learning new systems for remembering names.
Some manufacturers are selling tDCS devices directly to consumers. But these devices aren’t regulated by the FDA, and there is no guarantee they are safe or effective. I would avoid them.
I also would avoid going to a doctor who uses tDCS without studying its effects. It is an unproven treatment, though adverse effects seem to be few (temporary nausea, headache, irritation of the skin under the electrode).
More important, tDCS is of unproven value. For that reason, the thing to do, if you’re interested in trying tDCS, is to enroll in one of the many clinical trials seeking volunteers. To find one in your area, go to the study database maintained by the National Institutes of Health at www.clinicaltrials.gov.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.