rTMS

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive brain stimulation technique that uses rapidly changing magnetic fields produced by a coil placed on the scalp to induce electric currents in targeted areas of the cerebral cortex. These currents modulate neuronal activity and plasticity without the need for anesthesia or surgery, enabling neuromodulation of brain circuits implicated in mood, perception, and movement.

In a typical rTMS session, a technician positions a coil over a cortical target and delivers magnetic pulses at a specified frequency and intensity, often defined as a percentage of the patient’s motor threshold. Common targets include the left dorsolateral prefrontal cortex for mood regulation, although other regions such as the motor cortex may be used for rehabilitation. Stimulation parameters vary: high-frequency (>5 Hz) is generally excitatory, low-frequency (about 1 Hz) is suppressive, and intermittent theta-burst stimulation (iTBS) delivers brief bursts that produce similar effects to longer sessions in a shorter time. Typical course involves daily sessions, several weeks in length, with coil types including figure‑of‑eight for focal stimulation and H‑coil for deeper targets.

Indications and safety: rTMS is approved in many countries for treatment-resistant major depressive disorder, with regulatory approvals expanding to other conditions such as obsessive-compulsive disorder and post-traumatic stress disorder. Evidence supports effectiveness for depressive symptoms, with response and remission rates varying by protocol and patient characteristics. Common side effects are mild headache and scalp discomfort; rare risks include seizures. Contraindications include nonremovable ferromagnetic implants or devices in or near the head and a history of seizures. Patients are typically screened for implants and safety concerns prior to treatment.