Magnetic seizure therapy

Magnetic seizure therapy (MST) is a proposed form of electrotherapy and electrical brain stimulation. It is currently being investigated for the treatment of major depressive disorder, treatment-resistant depression (TRD), bipolar depression, schizophrenia and obsessive-compulsive disorder.[1][2] MST is stated to work by inducing seizures via magnetic fields, in contrast to ECT which does so using alternating electric currents. Additionally, MST works in a more concentrated fashion than ECT, thus able to create a seizure with less of a total electric charge.[3] In contrast to (r)TMS, the stimulation rates are higher (e.g. 100 Hz at 2 T) resulting in more energy transfer.[4] Currently it is thought that MST works in patients with major depressive disorder by activating the connection between the subgenual anterior cingulate cortex and the parietal cortex.[5]

Medical uses

Magnetic seizure therapy is a new treatment modality that is being studied for the treatment of multiple psychiatric conditions, including major depressive disorder, treatment-resistant depression (TRD), bipolar depression, schizophrenia and obsessive-compulsive disorder.[1][2]

Major depressive disorder and treatment-resistant depression

MST is currently being studied to as a potential treatment option versus ECT based on the need for a procedure with a different safety and side effect profile. Current limitations to a more widespread implementation of MST for these diseases are the variable dosages, number of treatments, and efficacy versus other treatment modalities.[3]

Procedure

MST is performed with the use of a modified rTMS device that delivers a higher output.[6] Similar to ECT, because MST induces seizures, general anesthesia is used to relax the muscles.[7] However, because there is not an electric current that may stimulate the jaw muscles, a bite block is not necessary.[7] Coils are placed over the frontal cortex (usually bilaterally) and the treatment dosage is usually determined via titration with a preset dosing schedule.[3] The treatment dosage is determined once the seizure threshold has been met and a sufficient seizure is produced.[3] Various coil designs have been tested, such as the figure 8 coil, double cone coil, and cap coil.[6] The latter two are the ones that have been most reliable in seizure induction.[6]

Mechanism of action

The mechanism of action of MST is not yet clearly understood.[8] One hypothesis focuses on the neuroplasticity of the affected areas of the brain, mostly including the hippocampus and amygdala.[8] Further recent imaging with fMRI has shown an effect on the connection between the subgenual anterior cingulate cortex and the parietal cortex.[5]

Adverse effects

Adverse effects include disorientation, emergence of mania, and superficial burns due to coil malfunctions.[9] While one study did note a decline in autobiographical memory after MST, many studies have noted no anterograde memory loss nor retrograde memory loss, both of which are more commonly seen side effects of ECT.[3][7] Other adverse effects include generalized seizures as well as side effects typically seen with general anesthesia.[10] Hearing loss is a possible adverse effect from the clicking noise of the magnetic coils if earplugs are not used.[10]

See also

References
  1. Clinical trial number NCT01596608 for "Magnetic Seizure Therapy (MST) for Treatment Resistant Depression, Schizophrenia, and Obsessive Compulsive Disorder" at ClinicalTrials.gov
  2. Tang VM, Blumberger DM, Dimitrova J, Throop A, McClintock SM, Voineskos D, et al. (September 2020). "Magnetic seizure therapy is efficacious and well tolerated for treatment-resistant bipolar depression: an open-label clinical trial". Journal of Psychiatry & Neuroscience. 45 (5): 313–321. doi:10.1503/jpn.190098. PMC 7850154. PMID 31922372.
  3. Daskalakis ZJ, Dimitrova J, McClintock SM, Sun Y, Voineskos D, Rajji TK, et al. (January 2020). "Magnetic seizure therapy (MST) for major depressive disorder". Neuropsychopharmacology. 45 (2): 276–282. doi:10.1038/s41386-019-0515-4. PMC 6901571. PMID 31486777.
  4. White PF, Amos Q, Zhang Y, Stool L, Husain MM, Thornton L, et al. (July 2006). "Anesthetic considerations for magnetic seizure therapy: a novel therapy for severe depression". Anesthesia and Analgesia. 103 (1): 76–80, table of contents. doi:10.1213/01.ane.0000221182.71648.a3. PMID 16790630. S2CID 21008547.
  5. Ge R, Gregory E, Wang J, Ainsworth N, Jian W, Yang C, et al. (May 2021). "Magnetic seizure therapy is associated with functional and structural brain changes in MDD: Therapeutic versus side effect correlates". Journal of Affective Disorders. 286: 40–48. doi:10.1016/j.jad.2021.02.051. PMID 33676262. S2CID 232135736.
  6. Rowny SB, Benzl K, Lisanby SH (September 2009). "Translational development strategy for magnetic seizure therapy". Experimental Neurology. 219 (1): 27–35. doi:10.1016/j.expneurol.2009.03.029. PMC 2997268. PMID 19348798.
  7. Cretaz E, Brunoni AR, Lafer B (2015). "Magnetic Seizure Therapy for Unipolar and Bipolar Depression: A Systematic Review". Neural Plasticity. 2015: 521398. doi:10.1155/2015/521398. PMC 4444586. PMID 26075100.
  8. Sun Y, Blumberger DM, Mulsant BH, Rajji TK, Fitzgerald PB, Barr MS, et al. (November 2018). "Magnetic seizure therapy reduces suicidal ideation and produces neuroplasticity in treatment-resistant depression". Translational Psychiatry. 8 (1): 253. doi:10.1038/s41398-018-0302-8. PMC 6251931. PMID 30470735.
  9. Daskalakis ZJ, Dimitrova J, McClintock SM, Sun Y, Voineskos D, Rajji TK, et al. (January 2020). "Magnetic seizure therapy (MST) for major depressive disorder". Neuropsychopharmacology. 45 (2): 276–282. doi:10.1038/s41386-019-0515-4. PMC 6901571. PMID 31486777.
  10. Singh R, Sharma R, Prakash J, Chatterjee K (October 2021). "Magnetic seizure therapy". Industrial Psychiatry Journal. 30 (Suppl 1): S320–S321. doi:10.4103/0972-6748.328841. PMC 8611602. PMID 34908721.
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