Anesthetic considerations for magnetic seizure therapy: a novel therapy for severe depression

Electroconvulsive therapy (ECT) is a highly effective treatment for severe depression. However, its use is associated with significant posttreatment cognitive impairment. Magnetic seizure therapy (MST) was developed as an alternative therapy that could reduce postseizure side effects through the induction of more "focal" seizure activity. Using an open-parallel study design, we compared 20 case-matched patients undergoing a series of either ECT or MST procedures with respect to their anesthetic, muscle relaxant, and cardiovascular drug requirements, effects on cardiovascular and electroencephalographic bispectral index (BIS) values, and early recovery times. We found that MST was associated with a reduced time to orientation (4 +/- 1 versus 18 +/- 5 min; P < 0.01) compared with ECT. To minimize residual muscle paralysis after MST, a reduction in the succinylcholine dosage (38 +/- 17 versus 97 +/- 2 mg; P < 0.01) was required. The BIS values were higher before, and lower immediately after, the stimulus was applied in the MST (versus ECT) group. The Hamilton depression rating scale score was significantly reduced from the baseline value in both treatment groups; however, the posttreatment score was lower after the series of ECT treatments (6 +/- 6 versus 14 +/- 10; P < 0.05). We conclude that MST was associated with a decreased requirement for muscle relaxants, reduced variability in the BIS values after seizure induction, and a more rapid recovery of cognitive function compared with ECT. Further studies are required to evaluate the antidepressant efficacy of MST versus ECT when they are administered at comparable levels of cerebral stimulation.