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What is a typical rTMS session?

A typical rTMS session lasts 25 to 40 minutes. Patients sit in a comfortable chair and use earplugs to protect their hearing from the loud “clicks” produced by each magnetic pulse.

In the first session, we determine the intensity of the magnetic stimulation needed to treat the patient. To do this, stimulation is applied over a spot on the patient’s scalp that corresponds to the brain region that controls the activity of either the right or left thumb. This spot is about 7.5 centimeters above the ear. Stimulation in this spot is made at different intensities until we are able to visually determine the lowest amount of energy needed to make the thumb move. This is called the motor threshold. Once the motor threshold is identified, the magnetic coil is moved to the specific area of the brain that will be therapeutically stimulated (e.g., the “prefrontal cortex” in depression). The location of this “target area” is determined according to a procedure called the 10-20 International System for Electroencephalography (EEG).

Patients are monitored continuously to ensure correct positioning and comfort level.

What are the main advantages of rTMS?

rTMS is a non-invasive procedure that requires no anesthesia or sedation. Thus, during rTMS sessions, patients remain awake and alert , and afterwards can return almost immediately to their regular activities.

Furthermore, rTMS treatment is not usually associated with the systemic side effects typically seen with the use of medications (e.g., weight gain, dry mouth, gastrointestinal discomfort). For these reasons, rTMS could be interesting for people who have not experienced significant relief from medications or who have had difficulties tolerating their side effects. However, rTMS is not right for nor does it work for everyone.

How does rTMS work?

rTMS is administered by a device called a “magnetic stimulator,” a machine that stores electricity and discharges it very quickly into a coil of electrical wire encased in plastic.

rTMS uses focused magnetic pulses to non-invasively “stimulate” or “inhibit” the activity of brain areas that are believed to be associated with the development of psychiatric disorders. For example, it aims to increase the activity of the left prefrontal cortex and/or decrease the activity of the right prefrontal cortex in the case of major depression.

During an rTMS treatment, the magnetic coil is gently placed against the patient’s scalp. The varying magnetic fields produced by the coil are able to penetrate up to two centimeters beneath the coil directly into the brain to induce electrical currents that can stimulate or inhibit neuronal activity depending on how often and how fast the magnetic pulses are administered.

When is rTMS treatment offered at the Douglas Institute?

Currently, rTMS is offered from Mondays to Fridays (except on holidays), from 9:00 A.M. to 4:00 P.M.

How long is a rTMS treatment?

Patients typically receive 20 to 30 rTMS sessions over a 3-6 weeks period.

Unless there is reasonable justification, patients who miss more than 5 rTMS sessions in total will not be able to continue with this treatment. Furthermore, patients must arrive on time to their rTMS session and no delays will be tolerated. This policy is strictly enforced and we encourage patients who are considering rTMS to make sure that they will be able to follow the intensive treatment schedule involved.

What are the main technical parameters in rTMS?

There are two basic ways of administering rTMS:

  • High frequency rTMS, in which magnetic pulses are given in very rapid succession (up to 20 pulses per second or 20 Hz for 2 to 4 seconds), followed by “no stimulation” intervals of 10 to 26 seconds, with this cycle being repeated until reaching up to 3,000 pulses per session
  • Low frequency rTMS, in which magnetic pulses are given at a rate of 1 pulse per second (1 Hz) “non-stop” for 10 to 20 minutes, until reaching up to 2,500 pulses per session

Generally speaking, high frequency rTMS  tends to "stimulate" and low frequency rTMS tends to "inhibit" the physiological activity of the underlying brain region.

How does rTMS compares to electroconvulsive therapy (ECT) in terms of efficacy and tolerability?

rTMS is less invasive and usually better-tolerated than ECT. However, a number of studies have shown that rTMS is likely less effective than ECT for treating major depression.

What is repetitive transcranial magnetic stimulation (rTMS)?

rTMS is a non-invasive neuromodulation treatment that involves the application of magnetic pulses to the scalp to help alleviate particularly the symptoms of major depression. Overall, rTMS has benefited between one-third and a half of the depressed patients who received it.

rTMS is a therapeutic procedure that has been approved for treating major depression by both Health Canada and the Food and Drug Administration (FDA) after more than 20 years of intensive clinical investigation.

Are there health risks associated with rTMS?

Yes. rTMS may cause a seizure (or convulsion), but this is very unlikely. Of the 50 000+ sessions that were performed to date, only around twenty have been associated with convulsions. They also occurred only with the use of high frequency rTMS. Since then, comprehensive safety guidelines for rTMS have been published, and the Douglas Institute Neuromodulation Program adheres to them.

Furthermore, all rTMS seizures have occurred while patients were under close observation, and none of them developed long-term adverse effects or a recurring seizure disorder, such as epilepsy.

However, a seizure may still occur even with settings that are currently considered to be safe and using low frequency rTMS. That is why we do appropriate seizure monitoring and management with:

  • regular visual inspection for signs of seizures
  • availability of a healthcare professional trained in seizure management
  • access to life-support equipment and to anticonvulsant medications

Am I going to be assessed during rTMS treatment?

Yes. Before and after the rTMS treatment, you will meet with a psychiatrist who is specialized in neuromodulation.

Should I stop taking my current medications before starting rTMS treatment?

No. Patients should continue to take the same medications that they were taking before starting with the rTMS treatment.

What are the most common side effects associated with rTMS?

Some patients experience mild to moderate muscle tension-type headache for up to a few hours after the first rTMS sessions, but common analgesics usually relieve it.

Also, some patients report a tingling sensation and/or mild scalp pain under the magnetic coil during stimulation, usually in the first week of treatment. Fortunately, there are several things that can be done to relieve significant scalp pain: analgesics, topical anesthetics, reduction of the intensity of stimulation, etc.

In a recent large study of rTMS in major depression, less than 10% of patients stopped treatment due to side effects.

Finally, rTMS has not been shown to be associated with cognitive impairments, such as memory loss, or inability to concentrate. On the contrary, it might even enhance some aspects of cognitive functioning.