Transcranial magnetic stimulation

Definition

Transcranial magnetic stimulation is a procedure that uses magnetic fields to stimulate nerve cells in the brain to improve symptoms of depression. Transcranial magnetic stimulation may be tried when other depression treatments haven't worked.

With transcranial magnetic stimulation, a large electromagnetic coil is placed against your scalp near your forehead. The electromagnet used in transcranial magnetic stimulation creates electric currents that stimulate nerve cells in the region of your brain involved in mood control and depression.

Because transcranial magnetic stimulation is a relatively new depression treatment, more studies are needed to determine how effective it is, which treatment techniques work best and whether it has any long-term side effects.

Why it's done

Depression is a treatable condition, but sometimes standard treatments aren't effective. Transcranial magnetic stimulation may be used when standard treatments such as medications and psychotherapy don't work. However, more research is needed to determine how well it works to relieve depression symptoms and in whom it may be most effective.

How it works
How transcranial magnetic stimulation helps relieve depression is not completely understood. It's thought that magnetic pulses stimulate nerve cells in the region of your brain involved in mood control. This stimulation appears to alter how this part of the brain is working, which in turn seems to ease depression symptoms and improve mood.

Risks

Transcranial magnetic stimulation is the least invasive of the brain-stimulation procedures used for depression. Unlike vagus nerve stimulation or deep brain stimulation, transcranial magnetic stimulation doesn't require surgery or implantation of electrodes. And, unlike electroconvulsive therapy, it doesn't require seizures or complete sedation with anesthesia. However, transcranial magnetic stimulation does have some risks and can cause some side effects.

Common side effects
Transcranial magnetic stimulation often causes minor short-term side effects. These side effects are generally mild and typically improve after the first week or two of treatment. They can include:

• Headache
• Scalp discomfort at the site of stimulation
• Tingling, spasms or twitching of facial muscles
• Lightheadedness
• Discomfort from noise during treatment

Uncommon side effects
Serious side effects are rare. They can include:

• Seizures
• Mania, particularly in people with bipolar disorder
• Hearing loss due to inadequate ear protection during treatment

More study is needed to determine whether transcranial magnetic stimulation may have any long-term side effects.

How you prepare

Before having the procedure, you may need a medical examination to make sure it's safe and a good option for you. You may be asked a number of questions about your depression. Tell your doctor or health provider if:

• You're pregnant or thinking of becoming pregnant.
• You have any metal or implanted medical devices in your body. Transcranial magnetic stimulation usually isn't recommended if this is the case.
• You're taking any medications, including over-the-counter medications, herbal supplements or vitamins. Bring a list of what you're taking to your doctor's appointment and include dosages and how often you take them.
• You have a history of seizures or mania. Tell your doctor about any past injuries or surgeries and about any other physical or mental health problems you have.

Little preparation is needed. Transcranial magnetic stimulation isn't invasive, doesn't require anesthesia and can be performed in a doctor's office. You don't need to arrange for someone to drive you home after treatment. Before considering treatment, however, check with your health insurance company to see whether transcranial magnetic stimulation is covered. Your policy may not cover it.

What you can expect

Transcranial magnetic stimulation is usually done on an outpatient basis in a doctor's office or clinic. It requires a series of treatment sessions to be effective. Generally, sessions are carried out daily, five times a week for four to six weeks.

Your first treatment
Before treatment can begin, your doctor will need to identify the best place to put the magnets on your head and will need to find the best dose of magnetic energy for you.

This is what will most likely occur during your first appointment:

• You'll be taken to a treatment room. You'll be asked to sit in a reclining chair, and you'll be given earplugs to wear during the procedure.
• An electromagnetic coil is placed against your head. The electromagnetic coil is switched off and on repeatedly, up to 10 times a second to produce stimulating pulses. This results in a tapping or clicking sound that usually lasts for a few seconds, followed by a pause. You'll also feel a light tapping sensation on your forehead. This part of the process is called mapping.
• The amount of magnetic energy needed is determined. Your doctor will increase the magnetic dose until your fingers or hands twitch. Known as your motor threshold, this is used as a reference point in determining the right dose for you. During the course of treatment, the amount of stimulation can be changed depending on your symptoms and side effects.
• Once the coil placement and dose are identified, you're ready to begin. The treatment itself will last about 40 minutes. The entire appointment typically lasts about one to two hours.

During transcranial magnetic stimulation
Here's what to expect during each treatment:

• You'll sit in a comfortable chair. The magnetic coil is placed against your head.
• The machine is turned on. You'll hear clicking sounds and feel tapping on your forehead.
• Each treatment session lasts about 40 minutes. You'll remain awake and alert. You may feel some scalp discomfort during the treatment and for a short time afterward.
• After treatment, you can return to your normal daily activities.

There are different ways to perform the procedure. Techniques may change as more is learned about the most effective ways to perform treatments.

Transcranial magnetic stimulation

Transcranial magnetic stimulation

In transcranial magnetic stimulation, an electromagnetic coil is held against the scalp. This creates a magnetic field that stimulates the brain. ...

Results

Some research showed that transcranial magnetic stimulation improved depression symptoms, while in other studies it didn't seem to help. If transcranial magnetic stimulation works for you, your depression symptoms may improve or go away completely. Symptom relief may take a few weeks of treatment.

Transcranial magnetic stimulation may be less likely to work if:

• Your mental illness causes detachment from reality (psychosis)
• Your depression has lasted for four or more years
• Electroconvulsive therapy (ECT) has not worked to improve depression symptoms

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. The effectiveness of transcranial magnetic stimulation may improve as researchers learn more about techniques, the number of stimulations required and the best sites on the brain to stimulate.