Transcranial magnetic stimulation is an experimental procedure that uses magnetic fields to stimulate nerve cells in the brain in the hope of improving chronic depression symptoms. Transcranial magnetic stimulation is one of the newer types of brain stimulation methods designed to treat depression when standard treatment hasn't worked.
There are different ways to perform transcranial magnetic stimulation. But in general, a large electromagnetic coil is placed against your scalp near your forehead. The electromagnet creates painless electric currents that stimulate nerve cells in the region of your brain involved in mood regulation and depression.
Depression is usually a very treatable condition. Often, standard treatment with antidepressant medications, psychotherapy or electroconvulsive therapy can help improve even severe cases of depression.
But if standard depression treatment doesn't work, all hope isn't lost. Researchers are studying brain stimulation as the newest frontier in depression treatment. Transcranial magnetic stimulation is one form of brain stimulation being tested as a possible treatment option. This procedure is still experimental and hasn't been approved by the Food and Drug Administration as a depression treatment.
Because it's experimental, transcranial magnetic stimulation isn't recommended as a first treatment option for depression. It's used only as a research tool and is generally available in the United States only through clinical trials. In countries where transcranial magnetic stimulation has been formally approved to treat depression, it's typically used only for people with depression that hasn't improved with standard treatments or for those who may be considering electroconvulsive therapy but want an alternative.
People who have long-standing depression or depression that hasn't improved with standard treatments may be eligible to participate in a clinical trial of transcranial magnetic stimulation. Talk to your doctor to see if it may be a good option for you. Transcranial magnetic stimulation may also be used experimentally in other mental health disorders, such as post-traumatic stress disorder, obsessive-compulsive disorder and bipolar disorder.
Transcranial magnetic stimulation is the least invasive of the brain stimulation procedures used for depression. It requires no surgery or implantation of electrodes or nerve stimulators. While it's considered generally safe, it's not without some risks.
Common side effects
Common side effects and adverse health problems associated with transcranial magnetic stimulation include, but may not be limited to:
- Scalp discomfort at the site of stimulation
- Tingling, spasms or twitching of facial muscles
- Discomfort from noise during treatment
Uncommon side effects
In rare cases, transcranial magnetic stimulation may also cause more serious side effects, including:
- Hearing problems
Because transcranial magnetic stimulation involves changes in brain function, unknown long-term adverse health effects are possible. Some studies have shown structural changes in the brain after transcranial magnetic stimulation. The significance of these changes isn't yet known. Also, the long-term effects of exposure to the strong electromagnetic fields involved remain unknown.
Because transcranial magnetic stimulation is experimental, it's generally available only through participation in clinical trials. Before having the procedure, you may need to have a medical evaluation to make sure it's safe for you and a good option in your case. You may need a full physical and psychiatric evaluation. But because transcranial magnetic stimulation isn't invasive, doesn't require anesthesia and can be performed in a doctor's office, little other preparation is needed.
Transcranial magnetic stimulation is usually done on an outpatient basis in a doctor's office or clinic that's running a clinical trial for the procedure. There are different ways to perform the procedure. Techniques may change as more is learned about the most effective ways to use transcranial magnetic stimulation.
In general during transcranial magnetic stimulation, an electromagnetic coil is placed against your scalp on an area near your forehead, often on the left side. To produce the stimulating pulses, the electromagnetic coil is switched off and on repeatedly, sometimes up to 10 times a second. This results in a tapping or clicking sound that usually lasts for a few seconds, followed by a pause. This process is repeated for the duration of the treatment session, which lasts about 30 to 40 minutes.
Although transcranial magnetic stimulation is generally painless, it may cause the muscles of your scalp or jaw to contract, which can be uncomfortable. Talk to your doctors about taking an over-the-counter pain reliever before the procedure if you're worried about discomfort. Also, wear earplugs during the procedure to reduce the risk of hearing problems.
It's not clear precisely how transcranial magnetic stimulation may help relieve symptoms of depression. Networks of brain regions may play a role in mood regulation. Stimulating the brain in these regions can change how the brain functions and may lead to mood improvement.
During transcranial magnetic stimulation, the magnetic pulses create painless electrical currents in your brain. These currents stimulate nerve cells in the region of your brain involved in mood regulation and depression. In some types of transcranial magnetic stimulation, brain activity is suppressed. In other types, brain activity is increased.
Researchers are still trying to determine the best dosage of stimulation and the best area of the brain to stimulate. The amount of stimulation can be changed depending on your symptoms and side effects.
Transcranial magnetic stimulation generally requires multiple treatment sessions. You may have the procedure every weekday for two weeks, for instance. After each treatment with transcranial magnetic stimulation, you can go about your normal daily activities.
If transcranial magnetic stimulation works, your depression symptoms will improve or go away completely. Improvement in your mood may last for days or weeks. Some research, however, shows a lack of dramatic improvement in depression symptoms. But as researchers learn more about different techniques, the number of stimulations required and the best sites on the brain to stimulate, the effectiveness of transcranial magnetic stimulation may improve over time.
Some research suggests that transcranial magnetic stimulation is less effective in certain situations, including:
- Older age
- Presence of psychosis
- Depression that has lasted four or more years
It's not yet known if transcranial magnetic stimulation can be used to treat depression for the long term, or whether you can have periodic maintenance treatments to prevent depression symptoms from returning.