From the Guidelines
Transcranial Magnetic Stimulation (TMS) is a non-invasive brain stimulation technique that uses magnetic pulses to stimulate nerve cells in the brain, primarily used to treat depression and other neuropsychiatric disorders. The treatment involves the use of an electromagnetic coil placed against the scalp, which generates magnetic pulses that stimulate nerve cells in the prefrontal cortex, regulating mood 1.
Mechanism of Action
TMS works by modulating neural activity in mood-regulating circuits that are often underactive in depression. The standard protocol uses high-frequency stimulation to the left dorsolateral prefrontal cortex, though protocols vary 1.
Treatment Parameters
The typical regimen involves daily sessions lasting about 30-40 minutes, five days per week for 4-6 weeks. Stimulation parameters, such as duration, number of stimulation sessions, stimulation frequency, intensity, target brain region, and interval between treatments, should be investigated to define the dose response of TMS techniques 1.
Side Effects and Safety
Side effects are generally mild and include headache, scalp discomfort, and rarely seizures (risk <0.1%) 1. TMS requires no anesthesia, and patients can drive themselves to and from appointments.
Insurance Coverage
Insurance coverage has improved in recent years, though prior authorization is typically required, and patients must usually demonstrate failure of multiple antidepressant medications before qualifying for coverage 1.
Future Directions
Future studies should focus on personalizing TMS treatment and optimizing stimulation parameters, electrodes/coil size and shape, duration, and number of stimulations 1. Additionally, the use of computational electric field modeling can provide highly individualized information to estimate the optimal coil position and orientation in order to induce the desired stimulation intensity and focality at the targeted location 1.
From the Research
Definition and Overview of Transcranial Magnetic Stimulation (TMS)
- Transcranial Magnetic Stimulation (TMS) is a non-invasive brain stimulation technique used to treat major depressive disorder (MDD) and other conditions 2, 3, 4, 5, 6.
- TMS involves the use of magnetic fields to stimulate nerve cells in the brain, with the goal of improving mood and reducing symptoms of depression.
Types of TMS
- Repetitive TMS (rTMS) is a type of TMS that involves repeated pulses of magnetic stimulation, often used to treat MDD 4, 6.
- High-frequency rTMS to the left dorsolateral prefrontal cortex (DLPFC) and low-frequency rTMS to the right DLPFC are common protocols used in TMS treatment 6.
- Newer forms of rTMS paradigms, such as theta burst stimulation (TBS), prolonged iTBS (piTBS), accelerated rTMS (aTMS), deep TMS (dTMS), priming TMS (pTMS), synchronized TMS (sTMS), and magnetic seizure therapy (MST), are being developed to improve antidepressant response and remission rates 6.
Efficacy and Safety of TMS
- TMS has been shown to be an effective treatment for MDD, with response rates ranging from 58-83% and remission rates ranging from 28-62% 3, 5.
- TMS is generally considered safe, with few side effects and low medical risk 2, 5.
- The efficacy and safety of TMS have been demonstrated in numerous clinical trials and registry studies, including those using the Standard TMS protocol and the "Dash" protocol 2, 3, 5.