Deep TMS vs Standard TMS: H-Coil and Figure-8 Compared

Deep TMS and standard TMS use the same principle, a magnetic pulse that induces current in the brain, but different coils. Standard TMS uses a figure-8 coil that stimulates a small, fairly shallow area under its center. Deep TMS uses BrainsWay's H-coil, which reaches further below the surface but spreads its field over a larger volume of brain. Both are FDA-cleared for adult major depression.

For depression, the honest summary is that neither has been shown to be clearly better. Head-to-head evidence is limited to one independent randomized trial, which found similar remission rates and a better response rate with the H-coil. The real differences are in cleared indications, session length, sensation and a higher seizure rate reported with the H-coil in one clinician survey (though the absolute risk was low), all covered below.

The physics: depth vs focus

Every TMS coil faces the same constraint. The induced electric field fades with distance from the coil, so stimulating deeper means either more power or a coil shape that spreads the field. A simulation study of 50 coil designs found that all of them followed a "depth-focality tradeoff": coils that reach deeper "cannot be as focal as more superficial coils".

• The figure-8 coil has two loops side by side. Their fields add up at the junction, producing a focused hotspot on the outer cortex. It is precise, which is useful when the goal is a specific spot such as a mapped DLPFC target.
• The H-coil (its developers called it the Hesed coil) has a more complex winding built into a helmet. In its first human test, it activated the motor cortex from 5.5 cm away, compared with 2 cm for a figure-8 coil. Different H-coil versions are shaped for different targets; the H1 coil is the one used for depression.

"Deep" is relative. Neither coil directly stimulates structures in the center of the brain at treatment intensity. Both act mainly on cortex and influence deeper regions through connected networks, as explained in how TMS works.

Side-by-side comparison

Session times on any device also depend on the protocol chosen and the device settings, so ask the clinic for the specific schedule it plans to use.

Cleared indications by coil

Online sources often say deep TMS is the only TMS cleared for OCD. That was true in 2018 but is not true now.

Separately, in June 2026 FDA cleared the first TMS-based system for PTSD, Wave Neuroscience's MeRT System, as an adjunct for adults; it pairs an EEG-based algorithm with MagVenture hardware, not the H-coil.

The OCD treatment that BrainsWay studied is a distinct protocol: 20 Hz stimulation over the medial prefrontal and anterior cingulate cortex after individualized symptom provocation. In its pivotal trial of 99 patients, response was 38.1% with active treatment vs 11.1% with sham at the end of treatment. More on this is in the patient guide to TMS for OCD.

What the depression evidence shows

Each coil against sham

Both coils beat sham in their pivotal trials. In the deep TMS trial (Levkovitz 2015), the intention-to-treat response rate at week 5 was 37.0% vs 27.8%, and remission was 30.4% vs 15.8%. The headline numbers in that paper's abstract come from the per-protocol group, and the intention-to-treat primary endpoint narrowly missed significance. For the figure-8 coil, the independent NIMH OPT-TMS trial reported remission of 14.1% vs 5.1% with sham. These trials used different scales, durations and patient groups, so their numbers cannot be compared directly.

The one independent head-to-head trial

Filipčić and colleagues in Croatia ran an industry-independent, single-blind trial of 228 patients randomized to 20 sessions with the H1 coil, 20 sessions with a figure-8 coil, or medication alone, with both TMS groups also on standard medication. Remission at week 4 was 60% with the H1 coil and 43% with the figure-8 coil, a difference that was not statistically significant; both beat medication alone at 11%. Response was significantly better with the H1 coil, and depression scores fell 59% vs 41%. Safety and tolerability were comparable.

One trial, single-blind and not replicated, is not enough to call deep TMS superior. It is enough to say that both are effective and that a modest advantage for the H1 coil is possible.

Meta-analyses and registries

A 2017 network meta-analysis found that deep rTMS, along with accelerated and synchronized forms, was not more effective than sham, but that conclusion rested on a small evidence base as of its 2016 search and conflicts with the positive deep TMS trial. Large BrainsWay-affiliated registry reports show response rates above 80%, but they are open-label, partly self-rated and counted only patients with data at 30 sessions, so they should not be set beside randomized results. The article on response vs remission explains why those figures differ so much.

Safety and sensation

Side effects are similar in kind. In the deep TMS pivotal trial, headache occurred in 26.7% of active vs 18.9% of sham patients, and application-site pain was the only side effect significantly more common with active treatment (5.0% vs 0%). Because the H-coil spreads its field more widely, the tapping sensation may be felt over more of the forehead and scalp, while a figure-8 coil concentrates it at one spot; muscle twitching of the face or jaw can occur with either. The patient guide What does TMS feel like? describes the experience in more detail.

Three safety points differ by coil:

• Seizure. In a survey of Clinical TMS Society members covering more than half a million sessions, the H-coil rate was 5.56 per 1,000 patients vs 0.14 per 1,000 for the most-used figure-8 devices, a significant difference. The authors described the absolute risk as low and the relative risk as higher with the H-coil, and the data came from a voluntary survey. Screening matters with either coil; see TMS safety and seizure risk.
• Hearing. Earplugs are required with all TMS. The one reported case of a permanent small hearing threshold shift occurred when an earplug slipped out during H-coil stimulation.
• Pregnancy. The safety guidance on TMS in pregnancy rests mostly on figure-8 coil data; safety data for the H-coil in pregnancy "are not yet available".

Insurance differences

The payer policies reviewed for this guide turn on whether the device is FDA-cleared for the condition rather than on coil type; New York Medicare's policy, for example, requires a device that is FDA-approved or -cleared for major depression. Aetna does not separately exclude deep TMS for depression, but notes there is no evidence that people who fail one TMS device will respond to another brand or to deep TMS. Coverage for OCD differs sharply: New York Medicare's LCD states deep TMS is "not considered reasonable and necessary" for OCD, while Cigna's policy covers deep TMS for OCD in adults who meet its criteria. Plan-by-plan details are in the guides to Medicare TMS coverage in New York, Aetna and Cigna.

How to choose

For most adults with depression, the coil matters less than accurate targeting, correct dosing, a full course and a psychiatrist who reviews progress. Situations where the choice does matter:

• OCD: both coil types now hold OCD clearances, but the large multicenter sham-controlled OCD trial described above used deep TMS. Ask what protocol and evidence a clinic is relying on.
• Smoking cessation: the cleared protocol is a deep TMS one.
• Seizure risk factors: given the higher relative seizure rate in survey data, a figure-8 coil may be the more conservative choice for someone with borderline risk factors, a judgment for the treating psychiatrist.
• Time: theta-burst sessions on figure-8 systems last about 3 minutes, which can matter for people fitting treatment around work.
• A previous course: if one approach helped before, repeating it is reasonable. If it did not help, switching coils is not proven to work.

Questions to ask a clinic

• Which device and coil will be used, and which FDA-cleared protocol?
• How long is each session, how many sessions are planned, and over how many weeks?
• How is the target located, and how often is the motor threshold re-checked?
• How will progress be measured, and what happens if there is no improvement by mid-course?
• Who supervises treatment, and who is on site if a side effect occurs?

The answers matter more than the coil label. A clinic that can explain its protocol, its measurement plan and its supervision is more informative than one that leads with the device's brand. The roles involved are described in who delivers TMS.

For the full device landscape, see TMS devices compared. The TMS guide collects every article in this series, and the TMS therapy page explains how TMS fits into psychiatric care.

Frequently asked questions

Is deep TMS more effective than regular TMS?

Not clearly. The only independent head-to-head trial found similar remission rates, with a better response rate for the H1 coil. One single-blind trial is not enough to call either coil superior.

Does deep TMS reach the emotional centers of the brain directly?

Not at treatment intensity. The H-coil reaches further below the surface than a figure-8 coil, but both act mainly on the cortex and influence deeper regions through their network connections.

Is deep TMS the only TMS cleared for OCD?

No. BrainsWay Deep TMS was the first, in 2018, but several figure-8 systems, including MagVenture and NeuroStar, have since been cleared as an adjunct for adult OCD.

Does deep TMS hurt more?

Experiences vary. The H-coil stimulates a broader area, which some people find feels more diffuse. In the deep TMS pivotal trial, headache was the most common side effect and application-site pain was the only one significantly more frequent than with sham; TMS side effects are usually mild and temporary.

If standard TMS did not work for me, should I try deep TMS?

Aetna's coverage policy notes there is no evidence that people who do not respond to one TMS device respond to another brand or to deep TMS. Your psychiatrist may still consider it, along with other options such as a different target, a different protocol, esketamine or ECT.

Sources

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Educational information, not medical advice. Whether TMS or any treatment fits you is a decision to make with a psychiatrist who knows your history.