Medicine: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] A Cochrane review (2021) with three studies (65 participants) found insufficient evidence of a difference between MST and ECT.[6]
Procedure
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
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
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
- Electroconvulsive therapy (ECT)
- Harold A. Sackeim
- Sarah Lisanby
References
- ↑ 1.0 1.1 Clinical trial number NCT01596608 for "Magnetic Seizure Therapy (MST) for Treatment Resistant Depression, Schizophrenia, and Obsessive Compulsive Disorder" at ClinicalTrials.gov
- ↑ 2.0 2.1 "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. September 2020. doi:10.1503/jpn.190098. PMID 31922372.
- ↑ 3.0 3.1 3.2 3.3 3.4 "Magnetic seizure therapy (MST) for major depressive disorder". Neuropsychopharmacology 45 (2): 276–282. January 2020. doi:10.1038/s41386-019-0515-4. PMID 31486777.
- ↑ "Anesthetic considerations for magnetic seizure therapy: a novel therapy for severe depression". Anesthesia and Analgesia 103 (1): 76–80, table of contents. July 2006. doi:10.1213/01.ane.0000221182.71648.a3. PMID 16790630.
- ↑ 5.0 5.1 "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. May 2021. doi:10.1016/j.jad.2021.02.051. PMID 33676262.
- ↑ "Magnetic seizure therapy for treatment-resistant depression". The Cochrane Database of Systematic Reviews 2021 (6): CD013528. June 2021. doi:10.1002/14651858.CD013528.pub2. PMID 34131914.
- ↑ 7.0 7.1 7.2 "Translational development strategy for magnetic seizure therapy". Experimental Neurology 219 (1): 27–35. September 2009. doi:10.1016/j.expneurol.2009.03.029. PMID 19348798.
- ↑ 8.0 8.1 8.2 "Magnetic Seizure Therapy for Unipolar and Bipolar Depression: A Systematic Review". Neural Plasticity 2015: 521398. 2015. doi:10.1155/2015/521398. PMID 26075100.
- ↑ 9.0 9.1 "Magnetic seizure therapy reduces suicidal ideation and produces neuroplasticity in treatment-resistant depression". Translational Psychiatry 8 (1): 253. November 2018. doi:10.1038/s41398-018-0302-8. PMID 30470735.
- ↑ "Magnetic seizure therapy (MST) for major depressive disorder". Neuropsychopharmacology 45 (2): 276–282. January 2020. doi:10.1038/s41386-019-0515-4. PMID 31486777.
- ↑ 11.0 11.1 "Magnetic seizure therapy". Industrial Psychiatry Journal 30 (Suppl 1): S320–S321. October 2021. doi:10.4103/0972-6748.328841. PMID 34908721.
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