What Is Transcranial Magnetic Stimulation (TMS)?
Transcranial Magnetic Stimulation, or TMS, is an outpatient procedure in which a device is used to generate short pulses of magnetic fields in order to stimulate an area of the brain thought to be associated with depression. It is a non-invasive treatment that may be performed in a psychiatrist's office while the patient is awake. Initial treatment generally involves administering the therapy for about 35 minutes daily, five days a week, over the course of about four to six weeks.
How Does It Work?
The short pulses of magnetic fields generated by the device produce an electric current in the brain, which stimulates cells in an area of the brain that is believed to function abnormally in those with depression. This stimulation brings about changes in the brain that may alleviate depression.
Who Is a Candidate for It?
The NeuroStar TMS Therapy device, which is the only TMS device currently cleared by the U.S. Food and Drug Administration, is approved for the treatment of major depression -- in particular, an episode of depression that has failed to respond adequately to one antidepressant trial.
TMS does not cause any of the troublesome side effects often experienced with antidepressant therapy -- such as weight gain, sexual dysfunction, nausea, dry mouth and sedation -- and thus may be appropriate in cases where patients experience intolerable side effects with antidepressants.
Who Should Not Receive It?
If you have an implanted metallic device or metallic objects in or around the head that cannot be removed, you should not receive TMS. You should also not receive TMS if you have an implant such as a pacemaker or cardioverter defibrillator.
What Happens During the Procedure?
During the TMS procedure, you will sit in a chair, awake and alert during the entire treatment. You will be asked to wear earplugs because of a tapping sound made by the treatment device.
Prior to beginning the treatment, your psychiatrist will first give you a motor threshold test, in which he will determine the magnetic field strength required to cause movement in your thumb. This test determines the magnetic field strength that will be used in your treatment.
After the motor threshold test, your doctor will then determine where to place the treatment coil on your head to provide optimal treatment, and will move it to that location.
During the treatment, there will be pulses of magnetic fields every 30 seconds, which may feel like tapping on your scalp. Some patients may feel mild to moderate scalp discomfort during the procedure, which can be alleviated with an over-the-counter pain medication.
What Happens After the Procedure?
Immediately after the procedure you may return to your normal activity, including driving. You may experience a headache or discomfort at the site of the stimulation, which may be relieved using over-the-counter pain medication. These side effects should subside over time as you receive more treatments, but if they do not, your doctor can adjust the strength of the magnetic field pulses to make you more comfortable.
What Are the Risks?
You may experience mild to moderate scalp discomfort during treatment or scalp discomfort or headache following treatment.
There is a small risk that you could have a seizure during treatment. This risk, however, is similar to that of antidepressant medication.
You should be aware that not all patients will respond to TMS. If you experience worsening depression, signs or symptoms of suicidal behavior, or any unusual changes in behavior, contact your doctor.
What Are the Benefits?
TMS has proven to be effective in some individuals who have not adequately responded to an antidepressant trial. TMS has very few side effects compared to antidepressants and is generally well-tolerated by patients. It is non-invasive and does not affect concentration and memory, like electroconvulsive therapy. There are no interactions between TMS and antidepressants, so patients have the option of taking an antidepressant in addition to receiving TMS.
"Neurostar TMS Therapy." 2010. Neuronetics, Inc. Accessed: May 24, 2010.