Starting your transcranial magnetic stimulation (TMS) treatment journey is a significant step towards depression relief. Since gaining FDA approval in 2008, TMS has revolutionized depression treatment as an effective non-invasive therapy. Now, it’s an FDA-cleared treatment for various mental health and psychological conditions.

Clinicians administer TMS in a clinical setting. They use specialized coils to deliver magnetic pulses to specific brain regions linked to mood regulation. This well-tolerated procedure encourages neural activity, fostering recovery and growth in circuits associated with mood disorders like Major Depressive Disorder (MDD). As you begin, understanding the basics of TMS coils can help you discuss treatment plans with your provider.

The Coil Basics

As mentioned above, coils used in the stimulation process are central to the effectiveness of TMS. Coils generate and deliver magnetic pulses that stimulate brain regions associated with major depressive disorder (MDD). The FDA has approved two coils for TMS depression therapy:

1. The Figure-Eight (Double) Coil

As the smaller of the two primary TMS coils, the double coil can deliver more focused and precise stimulation. Because of this, it’s the more common coil for TMS depression treatment as it’s particularly good at targeting areas in the prefrontal cortex (the part of your brain associated with mood regulation). This allows for more personalized treatment instead of a one-size-fits-all treatment setting. You will find figure-eight coils on Neuronetics/NeuroStar and some MagstimTMS devices.

2. The H-Coil

H-coils are the larger of the two primary coils and typically have a complex winding pattern. According to “Brain Stimulation”, their greater size means the higher amplitude magnetic pulses can reach slightly deeper brain structures in a more extensive treatment area. However, their size also means TMS experts can’t focus the treatment field as much. This widespread treatment area does encompass a higher risk of seizure, though effective. You can find H-coils in BrainsWay TMS devices.

The figure-eight coil design allows for a more targeted approach, minimizing the spread of magnetic pulses to surrounding areas. At the same time, the H-coils are the better choice for deeper and more widespread magnetic pulses. However, researchers have rigorously tested both coils, demonstrating safety and equal results for treating depression in the clinical setting.

Bonus: The Double Cone Coil

While not FDA-approved, the double cone coil is FDA-cleared to treat MDD as well as obsessive-compulsive disorder (OCD). According to this research, it’s the most energy-efficient and best option of the three for stimulating deeper brain structures. It can reach targeted areas up to 6 cm deep. For its size, it can deliver a relatively focused magnetic pulse. However, there’s an increased risk of inducing seizures with this coil as that’s one of its clinical applications: magnetic seizure therapy. Some Magstim TMS devices have double cone coils.

Before You Start Treatment

Our TMS providers ensure you have plenty of time to ask questions during your initial consultation and at every treatment. Be prepared with questions or concerns when meeting with your TMS provider regarding coils or any other aspect of your treatment. Here are a few questions to get you started:

• Do you use different TMS coils for different purposes?
• What coil will you use for my treatment?
• Does the coil influence my treatment length or intensity?
• Are there any risks associated with this specific coil?
• What can I expect during the session in terms of sensations related to the coil’s magnetic pulses?

Ongoing Research

Like all dynamic medical fields, researchers continually explore new coil designs and technologies. For example, this study compared the two main TMS coils with double cone and Halo-circular assembly (HCA) coils. This study investigates the crown, C-core, circular, and double cone coils in addition to the H-coil and figure-eight coil with variations.

As technology advances, research progresses, and our collective understanding of brain circuitry deepens, new coil configurations may emerge. Coil technology will further refine TMS treatments for depression and other disorders. What won’t change is our need for an individualized approach. Remember, your journey to wellness involves not only the treatment itself but also collaboration between yourself and your healthcare providers to navigate tricky choices that pave the way to your recovery and reclaiming your mental well-being.