Magnetic Seizure Therapy (MST) is a developing, non-invasive brain stimulation technique. It is being investigated as a potential treatment for certain mental health conditions. It induces a seizure in the brain using magnetic fields. Introduced in 1998, MST aims to provide treatment with potentially reduced cognitive effects compared to other therapies.
The MST Procedure
Patients undergoing Magnetic Seizure Therapy undergo a structured process, beginning with a thorough medical evaluation to ensure suitability. Preparations include fasting for several hours before the procedure, as with other procedures requiring general anesthesia. An anesthesiologist assesses the patient’s medical stability for anesthesia, administered for comfort and safety.
Once under general anesthesia, a specialized magnetic coil is positioned on the patient’s scalp, typically over the frontal cortex. The coil delivers high-intensity magnetic pulses. Unlike electroconvulsive therapy, a bite block is not necessary because the magnetic current does not directly stimulate jaw muscles.
A series of pulses induces a therapeutic seizure. The seizure threshold is determined during an initial session, with subsequent treatments given at a higher dose. The induced seizure usually lasts 30 to 60 seconds, with total treatment time per session about 15 minutes.
Following the magnetic stimulation, patients are monitored as they recover from anesthesia. Post-procedure care focuses on reorientation and managing any transient side effects. Common effects reported after MST include headache, dizziness, nausea, muscle aches, and fatigue, related to the anesthesia or treatment.
How MST Works
Magnetic Seizure Therapy uses electromagnetic induction to generate controlled electrical activity within the brain. The therapy uses a modified transcranial magnetic stimulation (TMS) device that delivers powerful, rapidly changing magnetic pulses. These pulses pass unimpeded through the scalp and skull, reaching the brain tissue beneath.
As the magnetic fields rapidly change, they induce a focused electrical current in a targeted area of the brain’s cortex. This induced electrical current is strong enough to cause neuronal depolarization, thereby triggering a therapeutic seizure. The magnetic fields attenuate quickly, which helps to limit the effects of the induced electrical field to the superficial layers of the cortex.
The targeted nature of magnetic stimulation allows for a more localized seizure induction compared to other methods. This focality minimizes the impact on surrounding brain tissue and deeper brain structures, such as the hippocampus, involved in memory function. The precision of MST aims to achieve therapeutic effects while reducing widespread neural disruption.
Medical Applications
Magnetic Seizure Therapy is being investigated for treating various psychiatric conditions, with a focus on major depressive disorder (MDD). It is explored for individuals with treatment-resistant depression, where other interventions have not yielded sufficient improvement. Early studies indicate that MST can lead to a reduction in depressive symptoms for these patients.
Beyond depression, research is exploring MST’s applicability for other severe mental health conditions. These include bipolar depression, where it may offer symptom relief, and schizophrenia, for its antipsychotic effects. Some studies have considered its use in obsessive-compulsive disorder.
While initial findings show promise, the evidence is preliminary. Clinical trials are underway to establish the efficacy, safety, and optimal treatment parameters for MST across these conditions. The goal is to provide a new therapeutic option for individuals who have not responded adequately to existing treatments.
Comparison to Electroconvulsive Therapy
Magnetic Seizure Therapy (MST) was developed as an alternative to Electroconvulsive Therapy (ECT), addressing concerns with the older method. The key difference is the method of seizure induction. ECT uses direct electrical currents through scalp electrodes to induce a seizure, whereas MST employs powerful magnetic pulses for the same effect.
Another distinction is the seizure’s nature. ECT typically produces a generalized seizure, where the electrical current spreads broadly. In contrast, MST aims for a more focal and targeted seizure. The magnetic fields in MST pass through the skull without impedance, allowing for more concentrated electrical current induction in specific cortical regions, particularly superficial layers.
This difference in focality contributes to a different side effect profile. ECT is associated with cognitive side effects, including short-term memory loss, both for events around the time of treatment (anterograde amnesia) and sometimes for past memories (retrograde amnesia), as well as post-treatment confusion and prolonged reorientation time. These cognitive concerns are a consideration for many patients.
MST, due to its more targeted stimulation, has been associated with fewer cognitive side effects. Patients undergoing MST experience less memory impairment and shorter reorientation times after treatment than with ECT. While both therapies are administered under general anesthesia, the focused nature of MST’s magnetic induction mitigates some of the broader cognitive impacts seen with ECT’s less controlled electrical current distribution.