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BookmarkScienceDaily (Nov. 18, 2004) — Transcranial Magnetic Stimulation (TMS), a non-invasive technique that uses repeated short bursts of magnetic energy to stimulate nerve cells in the brain, is now being tested at Northwestern Memorial Hospital and Northwestern University's Feinberg School of Medicine as a potential treatment for participants with major depression. Northwestern will be one of 16 centers participating in the nationwide clinical trial to evaluate the effectiveness of TMS on participants who have not responded to antidepressant medications during efforts to manage their depression.
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"Through this trial we hope to prove the effectiveness of TMS as a treatment alternative for major depression," said Dr. William Gilmer, psychiatrist at Northwestern Memorial, Associate Professor of Psychiatry and Behavioral Sciences at Northwestern University Feinberg School of Medicine, and principal investigator for the Northwestern site. "We hope this treatment can provide another option to patients who haven't found success with many of the antidepressant medications currently available."
TMS produces about the same amount of magnetic energy as a standard MRI machine and works by sending pulses of magnetic energy aimed specifically at a portion of the brain called the left prefrontal cortex, which is thought to be involved with mood regulation.
The nature of magnetic fields allows the special pulses of energy to easily pass through the skull and into the brain. Once inside the brain, the magnetic pulses produce an electric field, which is thought to cause positive changes in mood. Participants remain fully awake during the 45 minute outpatient procedure and can resume their normal daily activities after the procedure. A TMS procedure is in no way similar to an electroconvulsive therapy (ECT) procedure - which requires a patient to receive anesthesia.
"The objective of TMS is to stimulate the "mood circuits" without causing a seizure. The stimulation applied to the brain is very focused, thereby reducing the risk of adverse effects, especially in comparison to ECT" Gilmer said.
This trial will involve an inactive (or sham) procedure to confirm if the antidepressant effect of TMS is real and durable and to identify participants who may improve simply because of the added attention they get in a research study, the so-called placebo effect. Neither the doctor nor participant will know which treatment - the active TMS or the sham - is being given since the sham device looks, acts and sounds like the real thing.
Smaller preliminary studies have encouraged researchers that TMS may produce an antidepressant effect. This larger and more rigorous trial will compare the effects of TMS on mood as compared to placebo and the information will be provided to the US Food and Drug Administration (FDA) to support regulatory clearance of the Neuronetics TMS System for clinical use in the treatment of major depression. If TMS is cleared by the FDA, it would be the first available non-drug procedure for depression since the introduction of electroconvulsive therapy (ECT) was first used in the 1930's.
Transcranial Magnetic Stimulation is already in use for brain mapping studies, diagnosis of neurological diseases and for research into a number of neurological and psychiatric conditions.
The Northwestern research study will be open to participants who are 18 to 70 years old, have been diagnosed with major depression as defined by the DSM-IV and have demonstrated resistance to antidepressant medications. Individuals who fit the criteria and are interested in participating can call Northwestern Memorial Hospital's physician referral department at 312/926-8400.
