Neurophysiological Characteristics of Magnetic Seizure Therapy vs. Electroconvulsive Therapy in Geriatric Patients with Severe Depression

Objective: Magnetic seizure therapy (MST) is under development as an alternative to electroconvulsive therapy (ECT), as it offers reduction in depression symptoms with fewer adverse cognitive effects. This study examined the feasibility and efficacy of MST versus ECT in a randomized trial of geriatric patients with severe depression, then compared the neurophysiological characteristics of seizures induced by MST or ECT and investigated potential links between seizure expression and therapeutic response. Method: Six patients (mean age: 64.8) with severe depression were randomized to receive MST (n=3) or ECT (n=3) until maximal antidepressant effect (mean number of sessions: 14.67). Depression symptoms were assessed preand post-treatment using the Hamilton Rating Scale for Depression. Neuropsychological tests of verbal ability, visuospatial ability, memory, fluency, executive functioning, and motor functioning were administered preand post-treatment. 64channel electroencephalogram (EEG) recordings were obtained at the start and end of treatment to capture power during ictal (seizure) and post-ictal periods for delta, theta, alpha, beta, and gamma frequency bands. Results: Two ECT and three MST patients achieved remission of depression symptoms. EEG power and test performance did not differ between treatments. Ictal power and post-ictal suppression increased from the start to end of treatment in all frequency bands for the responders but not the non-responder. Increases in gamma ictal power and post-ictal suppression predicted slowing on a task of visuomotor skill and executive functioning, while increases in beta and theta ictal power and post-ictal suppression predicted improvement on a task of verbal fluency. Conclusions: MST continues to show promise as an efficacious and feasible alternative to ECT. For both MST and ECT, increases in ictal power and post-ictal suppression in all frequency bands may be indicators of treatment response, and associated with impairments to visuomotor functioning.