FAQ

Neuromodulation is the process of modifying the brain’s circuitry or activity by directly targeting the nervous system, using electrical, ultrasound or magnetic energy that is applied on the scalp.

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation method used for the treatment of depression. rTMS uses magnetic fields to activate a specific region of the brain. By placing an electromagnetic coil on the scalp and transmitting magnetic pulses through the coil, overtime, gradual changes in the activity level of the stimulated brain region can be observed, as well as improved symptoms of depression.

Theta burst stimulation (TBS) is a new form of rTMS, where magnetic pulses are applied in bursts. By using TBS, the same number of pulses needed to provide treatment is delivered in a shorter amount of time, thus decreasing treatment sessions from what used to be 30-45 minutes to 3-4 minutes while maintaining the same efficacy.

Typical clinical rTMS is delivered on the left dorsolateral prefrontal cortex (DLPFC), a large region of the brain which tends to be under-active in its communication with other brain regions that regulate mood. By stimulating the DLPFC in a person with depression, TMS can effectively adjust its communication with the other brain regions and promote the reduction of depression symptoms.

Neuronavigation is a tool that can be used to precisely target a region of the brain. By undergoing a magnetic resonance imaging (MRI) scan, we are able to take structural images of a person’s brain. Based on the MRI image of the person’s brain, the neuronavigation system is able to reach specific brain targets. For more details on neuronavigation, you can visit this website: https://www.nest-lab.ca/learn-more

The most common side effects are mild discomfort or pain at the site of stimulation, muscle-type tension headaches, facial muscle twitching (while treatment is being administered), lightheadedness or dizziness. These side effects are usually temporary and can be effectively managed with rest, or over-the counter medication such as acetaminophen.

In less than 0.1% of cases there is a rare risk of epileptic seizures. Most of these occurred before 1998, when settings that we now know to be unsafe, were used. In 1998, safety guidelines for TMS were adopted, and since then, only a handful of additional episodes of seizure have occurred in the world. In most cases, patients were taking medications known to modify brain activity. All seizures that occurred stopped spontaneously with no long-term effects. Importantly, no one has ever developed epilepsy after an rTMS induced seizure.

In terms of the effectiveness of rTMS, the rates can vary across studies but generally range between 45-55% response rates, where response is defined by a significant improvement of depressive symptoms, and 30-40% remission rates, where remission refers to a complete resolution of depression symptoms.

At the Royal’s Neuromodulation Research Clinic we offer rTMS free of charge because it is conducted as part of clinical trials and is funded by research grants and philantropy. However, TMS is not currently covered by the Ontario provincial health plan, which means that you have to pay out of pocket in private clinics. TMS is currently covered by provincial health plans in Quebec, Saskatchewan and the Yukon.

Major depressive disorder (MDD) is a mood disorder, characterized by the persistent feeling of a depressed mood and/or loss of interest/pleasure. The standard or usual treatment for depression is medication and/or psychotherapy and while these standard treatments may work for many, some people will find that their symptoms will not improve, or improve only to return.

Treatment resistant depression is typically defined as the failure to respond to 2 or more adequate trials of anti-depressant medications. Approved by Health Canada in 2002, rTMS is considered a first-line recommendation for individuals that do not respond to at least one anti-depressant medication.

People with depression tend to have diminished brain activity in the frontal left side of the brain in comparison to their right side. For this reason, two types of rTMS treatments exist, aiming at either enhancing brain activity on the left frontal region or reducing brain activity in the right frontal region. Therefore, as used in our clinical trial as a treatment for depression, iTBS is used on the left side to enhance brain excitability, while cTBS is used on the right side to inhibit it.

A MRI is a non-invasive imaging procedure that uses magnets and radio waves in a scanner to produce images of your brain.

On the day of your MRI scan, you will undergo a 30-40 minute scan. You will lay still in the scanner, located in our Brain Imaging Centre, and undergo a brain scan. These swill produce images of your brain structure. Later, using neuronavigation, the images will help us target the location for the rTMS treatment.

Resting state functional connectivity is like a conversation between different parts of your brain when you are not doing anything in particular. Using an fMRI scanner, and a similar procedure to the MRI scan, we can take pictures of your brain while you are lying down and not doing anything specific. These images show which areas of your brain are active and how they are connected. By studying these patterns of communication, we can learn more about how the brain works and how different brain regions are connected in order to find the ideal location for treatment.

Our fMRI-guided vs. Standard iTBS trial will use fMRI images to find out if using a personalized treatment for TBS is better than using the standard technique for TBS, as used in our clinical trial, when treating depression. As identified from your fMRI scan, the fMRI-guided TBS targets specific locations in your brain based upon your personal patterns of brain connection when at rest, rather than using the general locations that have been effective, on average, for treating depression.