rTMS vs. Deep TMS | How Are They Different?

Depression is a common mental disorder that is the leading cause of disability worldwide, according to the World Health Organization (WHO) [1]. Functional imaging has shown that people with depression often suffer from impaired brain activity in certain areas, such as the prefrontal cortex along with specific structures that include the amygdala, hippocampus, and thalamus [2]. Although the precise location of functional changes has enhanced treatment methods for depression, a large number of people with this condition still respond poorly to conventional approaches.

Fortunately, transcranial magnetic stimulation or rTMS has shown promise as a noninvasive, non-medication treatment involving brain stimulation for people with depression who are drug-resistant or cannot take pharmaceuticals. Over the years, several adjustments have been made in the TMS field—with one such development involving the use of deep TMS, a procedure that reaches deeper areas in the brain.

Read on to learn more about rTMS vs. deep TMS.

What Does rTMS Mean?

Transcranial magnetic stimulation is a noninvasive, FDA-approved procedure in which magnetic pulses are delivered to nerve cells in the brain that regulate depressive symptoms and mood [3]. As this form of treatment stimulates the brain through repetitive magnetic pulses, it is more commonly referred to as repetitive TMS or rTMS. 

An rTMS session entails having magnetic coils placed on the scalp where they generate painless electromagnetic fields in areas of the brain (e.g., prefrontal cortex) associated with depression. The magnetic fields appear to minimize symptoms of depression by heightening activity in the targeted regions [3].

What is deep TMS therapy?

TMS has demonstrated effectiveness at treating depression in patients who do not respond well to pharmaceuticals (e.g., antidepressants) or even electroconvulsive therapy (ECT), by directly administering pulses to targeted regions of the brain located beneath the skull [3],[4]. Repetitive TMS (rTMS) demonstrates good efficacy and remission rates that often vary from person to person, but generally improve with treatment adherence and extended rounds of TMS therapy [5],[6]. 

Over the years as TMS research continued, deep TMS (dTMS) was established [7]. Deep TMS therapy is similar to rTMS in that magnetic pulses stimulate nerve cells in the brain by generating a gentle electric current [7]. However, the pulses are delivered through specialized coils that penetrate deeper layers of the brain—leading to improved response and remission rates for some patients, but also a higher risk of side effects that include an increased probability and frequency of seizures [7],[8].

How Is Deep TMS Different From rTMS?

The main difference between dTMS and rTMS is the structure of the coils that are used to deliver the magnetic pulses. Studies involving the use of various coils were conducted until it was discovered that one particular type of coil created a summation or accumulation of several electromagnetic fields across a larger and deeper cranial surface.

Depth and Scope of Magnetic Stimulation

The novel development—discovered through research—that allows dTMS to stimulate nerve cells in deeper regions of the brain is the H-coil. Standard rTMS is performed with figure-8 coils that target brain regions directly underneath the skull. More specifically, the unique structure of the H-coils allows stimulation at approximately 4 cm below the skull’s surface, while rTMS has a penetration depth of about 1 cm below the surface of the skull [9].

The increased stimulation depth of deep TMS therapy is achieved due to the thickness of H-coils that produce the magnetic pulses. Their unique design allows magnetic fields to accumulate in each layer of the H-coil, which helps the pulses penetrate deeper. However, there is no statistical difference between the effectiveness of rTMS and dTMS, even though the latter approach penetrates deeper regions.

In addition to reaching deeper regions, the H-coils also target larger areas of the brain (about 17 cm3), while standard rTMS figure-8 coils stimulate approximately 3 cm3 [8],[9]. The dramatic difference in depth and coverage area for dTMS is unfortunately associated with an increased risk of seizures for some patients who receive this particular form of TMS [10]. This is one of the main reasons that well-experienced professionals including the team at Dr. TMS Therapy Griffith Psychiatry prefers rTMS over dTMS.

Treatment Efficiency

Research shows that receiving rTMS for at least 3-5 weeks has helped patients experience improved symptoms of depression, with response rates of about 80% and remission rates around 40%—results that represent sustained improvement following one round of TMS therapy [11] [12]. However, rTMS is not only effective for people with depression who experience intolerable side effects from medication, but is also useful when combined with other treatments.

For example, there are cases where the addition of rTMS is preferred for patients who achieve a partial response to medication or when a clinician believes that taking the patient completely off of medication may be unsafe [11]. Fortunately, rTMS has demonstrated strong response and remission rates for patients with different therapeutic needs.

According to Dr. Griffith from Dr. TMS Therapy Griffith Psychiatry, “Although dTMS sounds like a technological breakthrough in comparison to rTMS, research suggests that depression treatment efficacy rates are not statistically different between the two approaches, meaning that dTMS is not better than rTMS. In fact, research shows that for some patients, dTMS is more dangerous due to the increased seizure rate that is linked to the penetration of magnetic fields into deeper regions of brain tissue [10]. For this reason, Dr. TMS Therapy Griffith Psychiatry does NOT recommend dTMS to patients. Until more research is released, we don’t feel comfortable offering dTMS to our patients.”

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Status of FDA Clearance

Research has repeatedly demonstrated the efficacy and safety of TMS for depression treatment through several clinical trials, including one clinical study that led to FDA approval in 2008 [13]. Shortly thereafter, TMS was also approved to treat migraines and obsessive-compulsive disorder [13]. 

TMS treatment is continuing to increase in popularity in the United States for treatment-resistant depression, also known as medication refractory unipolar major depressive disorder, due to the high response and maintenance rates [11], [12]. These benefits position TMS as a markedly effective option for depression treatment.

Overall, TMS uses advanced electromagnetic stimulation technology that offers optimal penetration of nerve cells through direct magnetic pulse delivery at safe and highly effective stimulation levels. Health professionals agree that rTMS helps reduce the risk of seizures and is the favored option for TMS treatment. By using rTMS, hypoactivity or hyperactivity of a particular area can be therapeutically modulated in specific regions that are associated with depressive symptoms—affording individuals an enhanced quality of life.

Consult The Dr. TMS Therapy Griffith Psychiatry Team About Getting TMS Treatment

If you’re struggling with depression that is resistant to medication or only provides partial improvement, consider receiving rTMS treatment at our office by contacting Dr. TMS Therapy Griffith Psychiatry. We offer rTMS treatment that directly targets the source of your depressive symptoms.

Our targeted rTMS technology excites impaired nerve cells deep in the brain to:

  • Reactivate healthy brain function
  • Minimize depression
  • Boost mood control

Most patients who did not experience relief from three or more antidepressants report significant improvement when they complete one cycle of rTMS treatment. You can experience similar health benefits and enjoy a better quality of life. To learn more about TMS treatment at our clinic, get more information here.

Walter G. Griffith Jr., MD, PA

Dr. Griffith earned his Undergraduate Degree from Notre Dame University and his Medical Degree from Ohio State University’s College of Medicine. He then completed his Residency in Psychiatry at Ohio’s prestigious Cleveland Clinic, and ultimately became the Chief Resident at the Cleveland Clinic in his final year of residency. After completing his residency, Dr. Griffith moved with his family to sunny Florida in 1992, where he worked at several hospitals in the early days of his career, but, ultimately, he decided to start his own outpatient Psychiatric Private Practice in Florida, where he has been working and growing the practice over the last three decades. Dr. Griffith is the Medical Director for the medical practice and oversees all of the medical clinicians who work in the practice in order to help manage the growing patient caseload at both of the medical office locations.

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