Transcranial Magnetic Stimulation (TMS) is a method that employs magnetism to stimulate small regions of the brain. TMS is a very safe and tolerable treatment with few medical exclusions although there are some conditions that are not compatible and these must be screened for. The first situation is the presence of any metal in or near the head or any implanted medical devices. Examples include cochlear implants, implanted electrodes/stimulators, aneurysm clips or coils, stents, bullet fragments, jewelry and hair barrettes. Any metallic object within the magnetic field would be at risk for overheating or possibly moving. Implanted medical devices risk malfunctioning. Other exclusions include any history of aneurysms, seizures, stroke, brain surgery, neurologic disorders, and active substance abuse. Once a patient has been evaluated and screened to see if they are appropriate for TMS, they can start treatment.
The first stage of treatment consists of mapping the brain to find the best treatment location. This is usually done on the very first session, which in total takes about an hour. Certain physical landmarks are identified on the head, specifically the nasion and the inion. The nasion is the distinctly depressed area directly between the eyes, just above the bridge of the nose. Inion is the bony prominence on the back of the skull. These landmarks and the nasion-inion distance are used to locate the starting point for locating the motor strip. The motor strip is the part of the brain responsible for controlling muscular movements. A significant portion of the motor strip represents the thumb and hand, which triggers thumb movement when stimulated at a specific location by a TMS machine. This location is used to determine how much energy is needed to elicit a muscular (in this case thumb) movement, which is the “motor threshold”. Treatment intensity is usually 120% of the motor threshold. This location also serves as the orientation point for the treatment location, which is 6cm towards the front of the brain. These measurements are all recorded on a fitted cap that is specific for each patient. Once the mapping and motor threshold determination phase is complete, treatment can begin.
The first Deep TMS treatment session starts at 100% of the motor threshold to allow the patient to acclimate to the treatment before going to a higher dose. The 100% dose is generally easier to tolerate than the target 120% dose. If the dose is gradually increased from 100% to 120%, most patients will acclimate well. Patients often describe a tapping sensation on the scalp, in addition to the sound of the electromagnetic pulse generation. The sound is similar to that of an MRI machine and is managed well with earplugs. The tapping sensation is generally tolerable. Some people may also experience headaches in the earlier stages of treatment, which is typically resolved with either ibuprofen (Motrin) or acetaminophen (Tylenol). Many patients report a significant reduction in these side effects after even just the first TMS session. Seizures, the most severe potential complication of TMS treatment, are very rare. Most patients acclimate well to the early stage side effects and can proceed with treatment.
A typical Deep TMS treatment course will consist of at least five days a week for four weeks, followed by two days a week for eight weeks. Another common treatment course starts with at least five days a week for six weeks, and then the frequency tapers down from there. The recommended minimum number of treatments is 36 while some TMS courses can have as many as 42 or more. Some patients will note an early response in the first three to four weeks, but many will take at least six weeks to really derive substantial benefits. Many of the patients that did not get a response within six weeks still derive a good response later in the treatment course, indicating the need to follow through with at least 36 treatments. After a successful course with 36 to 42 treatments, some may not require any further treatment while others may need short booster courses of three to six treatments a few times a year. Overall the success rate is very high.
In depression treatment, success is defined by rates of response and remission. It is important to note that in TMS studies, the patient population is a “treatment resistant depression” population that has failed four or more medications already. This population would be expected to have a significantly lower response rate to any type of therapeutic intervention than a conventional depression case. Even taking that factor into consideration, Deep TMS response rates after 30 sessions have reached 74% while full remission rates reach 49%. In comparison to other forms of depression treatment, these are extraordinarily high rates. Anecdotal reports suggest that response rates in non-treatment resistant depression patients are even higher. This supports the growing belief that TMS may one day become a first line treatment for Major Depression. Patients have increasingly asked for TMS to treat their depression before waiting to fail on four different medications. With the unequivocal results, an exceptional side effect profile, and the ability to produce long-standing brain changes through induction of neuroplasticity, this is no surprise. This is why Deep TMS has become the great new hope for treatment resistant depression.
Dr Rodriguez is the founder and Medical Director of the Delray
Center For Healing, the Delray Center for Brain Science, and the
Delray Center For Addiction Medicine. He is board certified in
both Adult Psychiatry and Addiction Medicine, with a clinical focus
on Treatment Resistant Depression, Bipolar Disorder, Anxiety
Disorders, Addiction and Eating Disorders. The Delray Center is
a comprehensive outpatient treatment center that incorporates the
most advanced psychotherapeutic and medical modalities, such as
Dialectical Behavioral Therapy (DBT) and Transcranial Magnetic
Stimulation (TMS), in the treatment of complex and dual-diagnosis
cases. www.delraycenter.com, www.delraybrainscience.com,