The Magnetic Brain Stimulator Will See You Now
By Marty Graham 05.22.07 | 2:00 AM
This transcranial magnetic stimulation device is made by Neuralieve, based in Sunnyvale , California .
SAN DIEGO -- The next time you visit a psychiatrist, don't be put off by the helmet-shaped device crawling with electrodes in the corner of the office. It's there to help.
Transcranial magnetic stimulation, a technique for treating clinical depression, uses a device placed on a patient's head that delivers a pulse to the gray matter. Psychiatrists at the American Psychiatric Association meeting here are unabashedly optimistic about its potential for treating tough cases. It's in the final stages of FDA review, and could come to market as soon as the end of the year.
"It's much less invasive -- patients can go home or go back to work afterwards," says Shirlene Sampson, an assistant professor at the Mayo Clinic College of Medicine. "And patients aren't exposed to social risk with their insurance companies and employers."
TMS works by creating an electromagnetic pulse that doesn't disturb the skull or scalp, but can reach two to three centimeters into the brain to stimulate the prefrontal cortex and paralimbic blood flow, increasing the serotonin output and the dopamine and norepinephrine functions.
"We have to be sure to get really good contact with the scalp so we reach the most effective areas of the brain," says Sampson. "In older patients where the brain has shrunk, we have to be very careful to get any results."
TMS can be done in an office setting and doesn't require anesthesia, which is needed for traditional ECT. Side effects include post-application headaches, muscle twitches and pain at the application site. The risk of seizure remains, but researchers worked very hard to avoid them, and they occurred very rarely.
Ten companies -- including five based in Europe, two American companies and two in Korea -- are now lined up to produce TMS headgear, which ranges in appearance from something like an ultrasound sensor mounted on a dental-drill arm to a cap resembling a beauty-parlor hair dryer.
Depression is increasingly recognized as a destructive, disabling, chronic illness with treatments that often fail patients. Studies yield conflicting results -- patients can respond well to placebos and exercise, while drugs can fail some and succeed for others. And short-term results often don't translate into long-term results as patients bolt from treatment because of side effects or lack of effect.
One of big problems in treating depression, where a bout is likely to lead to other bouts, is getting patients to stay on their therapy, studies show. And, while combinations of therapies initially seem to help the 30 percent and 40 percent of patients whose depression resists drug treatment, remission rates remain low and cures are elusive.
The downside is that it takes 20 to 30 sessions of 40 minutes each for at least six weeks to get a good result. But patients stick with TMS treatment better than with medication or electroshock, researchers say. It's also being tested for treating migraines.