Transcranial Magnetic Stimulation (TMS) is not a single, uniform treatment. It is a neuromodulation platform with several distinct protocols, each defined by technical parameters such as pulse frequency, coil design, and treatment schedule.
The primary types are Repetitive TMS (rTMS), Deep TMS (dTMS), and Theta Burst Stimulation (TBS).
Understanding these differences helps clinicians and patients choose the most appropriate option based on diagnosis, specific symptoms, and practical factors such as time and setting.
The sections that follow describe how each type works, how it is used clinically, and how they differ from one another.
Key Takeaways
- The three main TMS modalities are Repetitive TMS (rTMS), Deep TMS (dTMS), and Theta Burst Stimulation (TBS), which has its own technical features and clinical uses.
- Protocol choice depends on the illness being treated, how deep the brain target is, how long each session should last, and how the patient has responded to past treatments.
- All three methods are non‑invasive and work through similar brain mechanisms, but differences in coil design and pulse pattern determine how each is used and which conditions it is FDA‑cleared to treat.
The development of Transcranial Magnetic Stimulation (TMS) from a research technique to a standard clinical treatment has followed steady technical progress.
Early TMS used simple, repeated magnetic pulses, now called standard rTMS. Later, advances in coil design made it possible to stimulate deeper and wider brain areas, which led to Deep TMS.
Theta Burst Stimulation was developed as researchers learned more about the brain’s natural rhythms, and it allows for much shorter treatment sessions.
Today, the main TMS treatments used in clinics are rTMS, Deep TMS, and Theta Burst Stimulation. Each type works in a different way to change brain circuits that are involved in neuropsychiatric disorders.
Repetitive TMS (rTMS): The Foundational Protocol
Repetitive TMS (rTMS) is the oldest and most widely used form of TMS. It uses a figure‑8 coil placed on the scalp to create a focused magnetic field. [1]
This field reaches about 2-3 centimeters into the outer layer of the brain (cortex), which allows the clinician to target specific areas.
For Major Depressive Disorder (MDD), the usual target is the left dorsolateral prefrontal cortex (DLPFC), a region closely involved in mood control and executive function.
In the middle of this approach, several core technical features define standard rTMS for depression:
- Coil type: Figure‑8 coil for focused stimulation
- Stimulation depth: About 2-3 cm into the cortex
- Standard session length: About 20-40 minutes
- Primary indication: Major Depressive Disorder (MDD)
The term “repetitive” refers to the delivery of magnetic pulses in repeated trains at a set frequency. For depression, high‑frequency stimulation (often 10 Hz) is typically applied to the left DLPFC to increase activity in that area.
In some cases, low‑frequency stimulation (around 1 Hz) may be used over the right DLPFC, which tends to reduce activity. A usual acute course includes daily sessions, five days per week, for about four to six weeks.
This protocol has been used the longest, has FDA approval for depression since 2008, and many studies show it is effective and safe, forming the clinical foundation for systems such as NeuroStar Advanced TMS Therapy used in modern outpatient treatment settings.
Deep TMS (dTMS): Expanding the Reach
Deep TMS (dTMS) was developed to address a key limit of standard rTMS: it only reaches shallow brain areas. dTMS uses a special H‑coil placed on the scalp to produce a magnetic field that can reach about 4-6 centimeters into the brain.
This allows the treatment to influence deeper structures involved in mood regulation, such as the anterior cingulate cortex and medial prefrontal cortex.
The H‑coil also stimulates a wider area of the cortex, which may make coil positioning somewhat less sensitive than with a standard figure‑8 coil.
dTMS uses a special H‑coil placed on the scalp that creates a magnetic field reaching about 4-6 centimeters into the brain. This allows the treatment to affect deeper structures involved in mood, such as the anterior cingulate cortex and medial prefrontal cortex.
The H‑coil also stimulates a larger area of the cortex, which can make coil placement less exact than with a standard figure‑8 coil.
In the middle of this approach, several key features distinguish dTMS from standard rTMS:
- Coil type: H‑coil for deeper and broader stimulation
- Stimulation depth: Approximately 4-6 cm
- Target areas: Both cortical and deeper subcortical mood circuits
- FDA‑cleared indications: Major Depressive Disorder (MDD) and Obsessive‑Compulsive Disorder (OCD)
By reaching deeper and broader neural networks, dTMS has widened the clinical use of TMS.
It is effective for MDD and has FDA clearance for OCD, where it targets a different brain circuit than in depression. Session length is generally similar to standard rTMS, but dTMS acts on a more extensive network of brain regions.
It is often used for patients who did not improve enough with standard rTMS or when deeper limbic brain involvement is likely. The side effects are generally similar to rTMS, though some patients feel a different sensation because the stimulation covers a broader area.
Theta Burst Stimulation (TBS): The Efficient Paradigm
Theta Burst Stimulation (TBS) represents a significant innovation in treatment efficiency.
TBS does not send pulses at one constant speed. Instead, it sends short bursts of fast pulses (often 50 Hz), repeated at a slower “theta” rate (about 5 Hz). [2]
This pattern is designed to match natural brain rhythms and may create stronger and faster brain changes than standard rTMS.
The most common form, called intermittent TBS (iTBS), increases activity and is usually given to the left DLPFC for depression.
In the middle of this technique, several features make TBS distinct:
- Pulse pattern: Short bursts of high‑frequency pulses repeated at theta frequency
- Main clinical form: Intermittent TBS (iTBS), excitatory to the left DLPFC
- Session time: About 3 minutes for a full treatment dose
- FDA status: Cleared for Major Depressive Disorder since 2018
The main advantage of TBS is the much shorter session length. A full therapeutic dose of iTBS can be delivered in approximately 3 minutes, compared to 20-40 minutes for standard rTMS.
Studies show that iTBS can be non‑inferior to standard rTMS for treating depression. This makes TBS particularly useful for patients with limited time or difficulty tolerating longer visits.
A continuous form, called cTBS, provides an inhibitory effect and is used in different clinical settings. TBS is now increasingly offered in routine clinical practice.
Accelerated and Novel Protocols
Beyond these core types, research continues to explore accelerated and intensive protocols. The Stanford Accelerated Intelligent Neuromodulation Therapy (SAINT) protocol is a prominent example.
SAINT uses multiple iTBS sessions per day over about 5 days, often guided by functional MRI to tailor the target area for each patient.
Early research has shown remarkably high remission rates for severe, treatment-resistant depression, particularly with condensed treatment schedules similar to accelerated TMS protocols that deliver multiple sessions over a shorter time frame.
At this time, these methods are not standard in most community clinics and are often used off‑label, but they show where the field is heading, with a focus on faster and stronger treatment effects.
Another area of development is the use of “priming” protocols, in which a low‑frequency stimulation is given before a high‑frequency protocol, with the goal of enhancing brain plasticity.
The decision to use rTMS, dTMS, or TBS is made by the treating psychiatrist and is based on several factors, including:
- The specific diagnosis and symptom pattern
- Past treatment history and response
- Individual brain anatomy and tolerability
- Clinic equipment and available protocols
- Insurance coverage and practical access
At TMS of Tennessee, we use the NeuroStar Advanced Therapy system, which can provide both standard rTMS and the shorter iTBS protocols. This range of options allows us to tailor treatment to current clinical evidence and to each patient’s specific needs.
FAQ
What are the main types of TMS therapy used today?
The main transcranial magnetic therapy types include repetitive TMS (rTMS), deep TMS (dTMS), and theta burst stimulation (TBS). These TMS treatment modalities differ by coil design, stimulation depth, and session length.
FDA-approved TMS types focus on safety and proven outcomes. Newer approaches include accelerated TMS (aTMS) and navigated TMS (nTMS) for more targeted treatment planning.
How does rTMS differ from deep TMS and theta burst stimulation?
Repetitive TMS (rTMS) is a traditional method that uses a figure-8 coil rTMS to stimulate specific brain areas. Deep TMS (dTMS) uses an H-coil deep TMS design to reach deeper brain regions.
Theta burst stimulation delivers magnetic stimulation bursts in short sessions. These methods differ in treatment time, stimulation patterns, and depth of brain targeting.
What is theta burst stimulation, and why are sessions shorter?
Theta burst stimulation (TBS) delivers patterned TMS stimulation using fast magnetic pulses. Intermittent theta burst stimulation (iTBS) and continuous theta burst stimulation (cTBS) use short TMS session options that last only minutes.
TBS short session TMS works by copying natural brain rhythms. Prolonged intermittent TBS (piTBS) is studied for stronger and longer-lasting effects.
What is an accelerated and navigated TMS, and who may benefit?
Accelerated TMS (aTMS) uses multiple sessions per day TMS within a condensed TMS schedule. This approach aims for faster symptom improvement. Navigated TMS (nTMS) uses neuronavigation TMS and MRI guided therapy for precise brain targeting.
These advanced TMS techniques support customized treatment and help clinicians adjust stimulation based on individual brain structure.
Are there newer or experimental TMS therapy variants?
Newer TMS clinical variations include synchronized TMS (sTMS), quadripulse stimulation (QPS), and priming TMS protocols. Emerging TMS protocols test enhanced TMS protocols and unique TMS therapy variants.
Many focus on treatment resistant depression types. These approaches remain under research review while experts study safety, effectiveness, and long-term results.
Navigating TMS Treatment Options
Understanding the main types of TMS, rTMS, Deep TMS, and TBS, helps make the process clearer and supports informed choices. While they differ in technique, all are non‑invasive, do not require anesthesia, and have minimal systemic side effects.
They all aim to change brain circuits that are not working well, so symptoms improve and daily life becomes easier.
For patients considering TMS, the first step is a full visit with a qualified clinician. During this appointment, the provider reviews the diagnosis, the severity of symptoms, which treatments have already been tried, and practical issues such as schedule and insurance. Based on this information, the clinician recommends the TMS option that best fits the patient’s needs and goals.
If you’re ready to take that next step, TMS of Tennessee offers personalized NeuroStar Advanced TMS Therapy in a supportive setting, with treatment plans designed to fit your life and help you move forward without medication-based side effects.
References
- https://www.nimh.nih.gov/health/topics/brain-stimulation-therapies/brain-stimulation-therapies
- https://www.cambridge.org/core/journals/cns-spectrums/article/review-and-comparison-of-fdaapproved-transcranial-magnetic-stimulation-tms-protocols-for-depression/92AE9620B4B57C74036563E8C65C134E
