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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[edit]

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[edit]

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] A Cochrane review (2021) with three studies (65 participants) found insufficient evidence of a difference between MST and ECT.[6]

Procedure[edit]

MST is performed with the use of a modified rTMS device that delivers a higher output.[7] Similar to ECT, because MST induces seizures, general anesthesia is used to relax the muscles.[8] However, because there is not an electric current that may stimulate the jaw muscles, a bite block is not necessary.[8] 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.[7] The latter two are the ones that have been most reliable in seizure induction.[7]

Mechanism of action[edit]

The mechanism of action of MST is not yet clearly understood.[9] One hypothesis focuses on the neuroplasticity of the affected areas of the brain, mostly including the hippocampus and amygdala.[9] 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[edit]

Adverse effects include disorientation, emergence of mania, and superficial burns due to coil malfunctions.[10] 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][8] Other adverse effects include generalized seizures as well as side effects typically seen with general anesthesia.[11] Hearing loss is a possible adverse effect from the clicking noise of the magnetic coils if earplugs are not used.[11]

See also[edit]

References[edit]

  1. ^ a b Clinical trial number NCT01596608 for "Magnetic Seizure Therapy (MST) for Treatment Resistant Depression, Schizophrenia, and Obsessive Compulsive Disorder" at ClinicalTrials.gov
  2. ^ a b 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. ^ a b c d e 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. ^ a b 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. ^ Jiang J, Zhang C, Li C, Chen Z, Cao X, Wang H, et al. (Cochrane Common Mental Disorders Group) (June 2021). "Magnetic seizure therapy for treatment-resistant depression". The Cochrane Database of Systematic Reviews. 2021 (6): CD013528. doi:10.1002/14651858.CD013528.pub2. PMC 8205924. PMID 34131914.
  7. ^ a b c 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.
  8. ^ a b c 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.
  9. ^ a b 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.
  10. ^ 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.
  11. ^ a b 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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