By Kristin EllisFebruary 27, 2009
WASHINGTON (Army News Service, Feb. 27, 2009) - Walter Reed Army Medical Center this week became the first Department of Defense hospital to use Transcranial Magnetic Stimulation, a new treatment for depression.
TMS was just approved for use by the Food and Drug Administration in October and Walter Reed joined the ranks of only a dozen other treatment facilities in the country --such as Yale, Columbia University, and the Mayo-Rochester -- to offer it.
Depression affects 15 million American adults each year and doctors say finding a treatment that works may not always be easy.
"What may work for one person may not work for another, that's why we need different tools to be able to treat depression," said Lt. Col. Geoffrey Grammer, chief of Inpatient Psychiatry.
TMS therapy is used for patients who are not responding to at least one anti-depressant trial of an adequate length and dose, according to Grammer.
"We want to take these people not responding and offer them a relatively painless way of seeking treatment," he said.
TMS activates certain parts of the brain by generating a magnetic field through a coil device and applying it to the front part of the brain where mood is regulated. Quick pulses are sent to a small, precisely measured section of the patient's scalp. It does not require medication or sedation during the nearly 40-minute session, with the whole process lasting about four to six weeks, five times a week.
One in two patients experiences significant improvements, and one in three have complete symptom resolution. Because of the powerful magnetic field being generated, patients with pacemakers or metal in their head cannot receive the TMS treatment.
"We are stimulating the prefrontal cortex. There are millions and millions of nerves in this area and we are targeting a part the size of a quarter that gives you the sense of positive mood," Grammer said. "We're causing the nerve to activate, to fire, like it normally would. Then what happens over time is that you begin to change some of the nerve transmitters within deeper sections of the brain that have been known to be associated with depression."
He added that one of the main benefits of the new TMS machine is its accuracy.
Grammer demonstrated how that small portion of the brain is found with the help of a volunteer medical student, Ensign James Decker, who is not a patient and did not go through the 40-minute therapy.
By placing the "patient" in the TMS chair, similar to a dentist chair, and positioning the treatment coil near the common area that controls the thumb, Grammer fires off magnetic pulses and watches for Decker's right thumb to twitch.
"We localize by locating the part of the motor strip that's responsible for the thumb. That's our physiologic 'Hey, are we close''" he said. "You trigger the device and if you get twitching of the thumb, you're in the right spot. Once you've found that, you're going to come forward 5.5 centimeters and that is the area we try and stimulate."
Decker holds his thumb up like he's hitchhiking while Grammer sends out a pulse every five seconds, marked by a loud rattle from the machine. After finding the correct location, Grammer tests to see how much energy is needed to stimulate by sending the pulses in varying intensities.
"It's almost like a feather or something touching your head," Decker explained. "The noise is more annoying than the sensation. It's kind of startling because you're anticipating it."
Patients wear earplugs during the treatment to muffle the intense sound, which lasts for about 10 seconds. The most common side effects of the TMS therapy are mild scalp irritation and minor headaches. According to Grammer, less than 5 percent stop because of side effects.
"The patient can come in during [his or her] lunch break and go back to work. A lot of folks just actually fall asleep during the treatment," he said.
Grammer added that most people respond within a week or so, but if there is no response by week three, "you probably won't capture one later on." Of those who respond, only 10 percent relapse.
"I think there will be a better delineation over time as to who responds best to TMS and what conditions respond best to it."
As Walter Reed moves ahead with this new technology, other programs will be set up to study how magnetic stimulation may be harnessed to treat traumatic brain injuries, post traumatic stress disorder and chronic pain. Since the machine is a modular system, the manufacturer can send new devices that can change the coil behavior and move to different areas of the brain to stimulate in a different way for a different illness.
"Now that we actually have the technology and funding to start the program, I think we'll be in a unique position to ride that wave forward rather than chase it," he said. "We really are forging ahead and trying to be one of the pivotal first players for this."
(Kristin Ellis writes for the Stripe newspaper at Walter Reed.)