Brain Stimulation: Transcranial Magnetic Stimulation
No surgery required—magnetic pulses treat symptoms of depression and other conditions
By SARAH BALDAUF
July 15, 2009 RSS Feed Print
Patients who struggle to beat back the demons of depression have another option that is creating serious interest among clinicians and researchers. Transcranial magnetic stimulation (TMS) is a form of brain stimulation, which reorganizes a brain’s dysfunctional neural circuitry to the benefit of the patient. It’s currently being used for people suffering from depression that is treatment-resistant—meaning it doesn’t respond to the first-line approaches including lifestyle changes, psychotherapy, and antidepressant medications, but it is being studied for other uses, too. One big appeal: Unlike medications, it specifically hits the brain instead of the whole body So it is also offers an intriguing possible treatment for postpartum depression in women, say, who are breastfeeding and don’t want their babies to be exposed to drugs.
To deliver TMS, a clinician presses a device to the patient’s head to deliver magnetic pulses that reach about an inch deep inside the skull, causing electrical changes in targeted neurons. Typically, a TMS patient goes through a series of about half-hour treatments, usually several times per week over the course of a few weeks or maybe a month. But the results are temporary and may only last weeks or months; patients may need to return for an additional series of treatments if symptoms return. Side effects include headache, scalp discomfort, twitchy facial muscles, feeling light-headed, and being bothered by the loud noise of the machine. Less commonly, people can suffer seizures, mania, or hearing problems. Any long-term side effects are not yet known.
TMS therapy provides a more gentle option than electroconvulsive therapy (ECT), which has long been a next step for some patients when all else fails. While ECT has had a checkered past, techniques and research have refined the treatment, which induces a seizure to rejigger the brain’s circuitry. So electroconvulsive therapy remains a valuable option for some patients, particularly for depression. But TMS does not require inducing a seizure, which means it doesn’t entail anesthesia or a hospital stay. Nor does it appear to produce ECT’s cognitive side effects, such as memory loss. It is also far less invasive than deep brain stimulation, which requires surgery to implant a pacemaker-like device. (DBS is mainly used to treat movement disorders and Parkinson’s disease but is being tested against depression and other conditions).
And depression is not the only condition that investigators suspect TMS might treat. More than 200 clinical trials are underway to test the treatment for use against conditions including epilepsy, tinnitus (ringing in the ears), pain, Parkinson’s disease, Alzheimer’s disease, schizophrenia, and stroke. “You name it, if it involves the brain and its neurological and psychological [aspects], researchers are probably investigating TMS as a treatment or for diagnosis,” says Mehmet Dokucu, who is director of the Cancer Psychiatry Service at the Feinberg School of Medicine at Northwestern University and administers both TMS and ECT therapies to patients. (While not yet established as a diagnostic tool, TMS can excite and inhibit brain circuitry, so it’s being investigated as a potential means of testing brain function, say, after a stroke, he explains.)
A TMS device was cleared by the Food and Drug Administration last fall, but the technology isn’t widely available. Currently, patients must go to an academic medical center to get TMS treatments. And unless they are participating in a clinical trial, they generally pay out of pocket. A single treatment session can cost several hundred dollars, which can add up to several thousand dollars per treatment series.