A procedure referred to as repetitive transcranial magnetic stimulation, or rTMS, was developed in 1985 to test brain function in healthy individuals, and in those with various types of medical conditions. Recent studies, however, suggest that rTMS may also be used as a medical treatment for some psychiatric conditions, including depression.
When the brain is stimulated with rTMS, a magnetic coil is placed against the scalp about three inches beyond the hairline and to the left of the center of the head. The magnetic coil is made from two plastic loops, connected to look like a “figure 8.” Each of the two loops in the coil is about three inches wide.
rTMS works by creating magnetic pulses in the loops of the coil. These magnetic field pulses produce small electric currents that stimulate nerve cells in the brain. These magnetic pulses also stimulate muscles and skin in the scalp and cause a moderate tapping sensation to be felt in the scalp under the coil. rTMS does not involve passing electrical currents directly through the scalp. Therefore, in contrast to ElectroConvulsive Therapy (ECT), it does not require anesthesia.
The most promising use of rTMS is in the treatment of depression. Several studies, suggest that a several-week course of daily rTMS treatments may improve depression for up to several months. In addition, these studies suggest that rTMS is generally safe and does not cause the memory loss associated with ECT. In rare cases, rTMS has been reported to induce seizures.
Currently, treatment of depression with rTMS is an experimental procedure. Much more research will be necessary to prove the effectiveness of rTMS and determine the best ways to use rTMS (example: what parts of the brain should be stimulated, how fast, how often, etc.) to treat depression.
rTMS may someday provide an effective alternative to ECT. Because rTMS apparently has fewer side effects than ECT, it may be possible to someday use rTMS to treat milder cases of depression, or to use rTMS to speed improvement of depression being treated with antidepressant medications