Seizure induction is the goal of Magnetic Seizure Therapy (MST) in the treatment of depression. The device for MST is borrowed from repetitive transcranial magnetic stimulation (rTMS).
The advantage of MST is the ability to produce focal stimulation. Stimulation of areas likely to be most involved in the cognitive side-effects of ECT can be more easily avoided. From studies with ECT it is hypothesized that initiation of the seizure in the prefrontal cortex explains the efficacy of bilateral electrode placement and supratreshold unilateral electrode placement. Magnetic stimulation holds the promise of more precise control over current paths and current density in neural tissue. The scalp and scull are transparent to magnetic fields. With an electric stimulus as in ECT, the current is highly variable and the distribution widespread and their is little control over the intra cerebral current density.
A drawback of MST is similar to that of ECT, patients must receive general anaesthesia with muscle paralysis during the seizure induction.
Dr Shock was reading up on his literature. While reading a review about "Targeting abnormal neural circuits in mood and anxiety disorders..." in Nature Neuroscience he read about this new technique. Searching GoPubMed he discovered 20 articles of which 6 were relevant.
Publications about Magnetic Seizure Therapy
Of these publications there were two case reports and one publication about MST in rhesus monkeys. There was one clinical trial. It is free to read, as in free beer. Ten inpatients with depression participated in a randomized, within-subject, double-blind trial. They were treated with two ECT sessions and two MST sessions, raters were unaware of the treatment schedule. MST had shorter seizure duration, lower ictal EEG amplitude and less postictal suppression. MTS sessions gave fewer subjective side-effects. MST was alos superior to ECT on measures of attention an retrograde amnesia. Efficacy was not an outcome measure.
Conclusion about Magnetic Seizure Therapy
MST is feasible in depressed patients and appears to have a superior acute side effect profile. Antidepressant efficacy needs to be esthablished.
So it will take a while before Dr Shock might have to change his name to...Dr Magnet?
Related posts:
Deep Brain Stimulation
NICE information about ECT
Monday, September 3, 2007
Magnetic Seizure Therapy as Antidepressant Therapy
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