Does Electroencephalography Seizure Duration Account for an Adequate Treatment of Magnetic Seizure Therapy for Schizophrenia?

OBJECTIVES

A seizure lasting >15 s has been considered to indicate treatment for magnetic seizure therapy (MST), a modification of electroconvulsive therapy (ECT), without much validation. This study aimed to investigate whether this seizure duration was suitable for the treatment of schizophrenia.

METHODS

Altogether, 34 and 33 in-patients with schizophrenia received 10 sessions of MST and ECT, respectively. Clinical symptoms were assessed using the Positive and Negative Symptom Scale at baseline and at the 4-week follow-up. Electroencephalogram (EEG) was monitored during each MST or ECT treatment using bifrontal electrodes.

RESULTS

The proportion of participants who achieved the 15-second threshold was only 28.6% in the MST group, with a significant difference between responders and nonresponders. For patients receiving MST, the average EEG seizure duration correlated with the percentage of Positive and Negative Symptom Scale reduction ( t(32) = 2.51, P = 0.017, uncorrected; t(32) = 2.00, P = 0.055, corrected with clinical characteristics). The average EEG seizure duration predicted the clinical response at a trend level ( Z = 1.76, P = 0.078) with an optimal cutoff of 11.3 seconds. All patients in the ECT group achieved the 15-second threshold. However, their average EEG seizure duration was uncorrelated with clinical improvement.

CONCLUSIONS

The duration of EEG seizures may be associated with the antipsychotic effects of MST. This association may have been influenced by various clinical and technical factors. More research is needed to define the specific criteria for adequate MST in schizophrenia in order to achieve personalized dosing.