What is Deep TMS (DTMS)? Understanding how DTMS Compares to Standard TMS

Deep transcranial magnetic stimulation (DTMS) is an emerging psychiatric treatment. In this article, we’ll explain the principles of DTMS, discuss some of its uses, and explain how it compares to standard TMS procedures.

Basic Principles of TMS

Transcranial magnetic stimulation (TMS) is based on the idea that magnetic fields can influence electrical activity in the brain. During a TMS session, a coil is placed against the scalp that generates brief, rapidly changing magnetic pulses. These magnetic fields pass easily through the skull and create small electrical currents in the brain tissue underneath. The currents stimulate nerve cells, changing how they fire and communicate with one another.

Depending on the frequency of the pulses, TMS can increase or decrease electrical activity in specific regions of the brain. In treating depression, TMS is used to increase activity in the dorsolateral prefrontal cortex (DLPFC). This brain area is associated with learning, decision-making, and emotional regulation, and it’s typically underactive in people with depression.

The FDA first approved TMS for treating depression in 2008 and has since licensed the treatment for multiple other indications, including migraines, smoking cessation, and obsessive-compulsive disorder (OCD).

The most common and well-researched form of TMS in psychiatric treatment is repetitive TMS (rTMS). This is the procedure we use at McLean. During an rTMS session, a coil delivers a train of magnetic pulses to the scalp for about 30 minutes.

Understanding Deep-TMS (DTMS)

Deep transcranial magnetic stimulation (dTMS) works on the same principles as TMS, but is designed to influence electrical activity in deeper brain structures. The H-coil was developed to deliver dTMS in the early 2000s and was commercialised by the company Brainsway in 2003. The coil’s copper wires are arranged differently than in standard TMS devices to allow magnetic fields to penetrate further into the brain.

This deeper stimulation is designed to target neural circuits that may be less accessible with standard TMS, potentially benefiting patients who haven’t responded fully to standard TMS.

Comparing DMTS vs Standard TMS for Depression Treatment

A review published last year in the Journal of Neural Transmission sought to compare the benefits of DTMS with rTMS for patients with depression. They analysed the outcomes of three studies and found no significant difference in the quality of life or remission rates between those treated with rTMS and DTMS.

Additionally, side effects were more prevalent in the DTMS group compared to the rTMS group, with more patients experiencing headaches, discomfort at the application site, and insomnia after treatment. Overall, 9.4% of patients receiving DTMS dropped out of the studies due to unwanted effects or lack of effectiveness, compared to 4% in the rTMS group.

Deep Brain Structures Targeted by DTMS

The Anterior Cingulate Cortex

The anterior cingulate cortex (ACC) is a deeper brain structure that plays an important role in motivation, decision-making, and behaviours linked to reward and punishment. Dysfunction of the ACC is thought to contribute to several mental health disorders, including psychotic disorders. In a trial at the Shanghai Jiao Tong University School of Medicine in Shanghai, patients with treatment-resistant schizophrenia received DTMS that targeted their ACC. Positive and negative symptoms were significantly reduced after 20 treatment sessions.

The Prefrontal Cortex (PFC)

The prefrontal cortex (PFC) is highly connected to many areas of the brain, including deeper structures, and plays a key role in both cognitive and emotional functions. Researchers suggest that stimulating the PFC with DTMS can enhance its communication with other brain regions, including these deeper networks.

One important target is the striatum, a structure essential for controlling movement. Dysfunction in the striatum is a hallmark of Parkinson’s disease, and deep TMS has been explored as a potential treatment. However, clinical trial results have been mixed, with some studies showing benefits and others reporting limited effects.

Pros and Cons of DTMS

Pros:

• DTMS can access deeper brain structures than standard TMS. Theoretically, it can target areas involved in psychiatric disorders that can’t be accessed with regular TMS.
• Like standard TMS procedures, the treatment is non-invasive and doesn’t require any surgical intervention or anesthesia. Side effects are typically mild and wear off after treatment.
• Like standard TMS, it can provide benefits to patients with treatment-resistant disorders, including depression, OCD, and addiction.
• DTMS is FDA-approved for anxious depression, unlike rTMS, which is only approved for major depressive disorder (MDD) and TRD.
• DTMS may have benefits for Parkinson’s disease, although the clinical evidence is inconclusive.

Cons:

• DTMS is generally much more expensive than rTMS and other TMS protocols.
• The side effects of DTMS may be more prominent than those of other protocols.
• There’s no strong evidence to suggest that DTMS is more effective than rTMS when it comes to treating depression.
• There’s limited evidence on the long-term outcomes of DTMS treatment.

TMS Treatment at McLean NTC

McLean Neuropsychiatric Treatment Center (NTC) is proud to be a leading provider of TMS for depression in Fairfax County. Our team of psychiatrists and clinical staff is highly trained in administering these treatments safely and effectively, tailoring protocols to each patient’s needs.

If you’ve been struggling with depression and are curious about the benefits of TMS, we encourage you to get in touch with us. We can discuss whether the procedure is a suitable option for you and guide you through every step of the treatment process.