Seizure threshold manipulation in electroconvulsive therapy via repetitive transcranial magnetic stimulation. A novel way of augmentation?

Abstract

Introduction: A high seizure threshold (ST) is an impeding factor in certain patients, potentially preventing a successful electroconvulsive therapy (ECT) treatment. Several pharmacological and non-pharmacological methods have been put forward to augment ECT in such patients, however, to this date, only a handful of case reports existed about the potential role of repetitive transcranial magnetic stimulation (rTMS), as an augmentation method. Objectives: and Methods: In this randomized, double-blinded, sham controlled study, we set out to test the hypothesis of whether the application of high frequency transcranial magnetic stimulation (HF rTMS) lowers the seizure threshold for electroconvulsive therapy and whether it has an effect on other aspects of ECT treatment, such as seizure duration (SD), efficacy and safety. Results: 46 patients treated for a major depressive episode, indicated for ECT, were recruited to this study. A significantly lower seizure threshold was observed in the experimental group during ECT titration, on average a decrease by 34.55%, from 34.23 mC to 22.4 mC, p < 0.001 (Wilcox test). We had not observed a significant effect of TMS stimulation before ECT on seizure duration or clinical outcome. Another potentially important observation of this study is that 4 patients in the experimental group developed transient symptoms of hypomania/mania, all of which were stabilized after the combined stimulation protocol was halted spontaneously within a week, without the need to administer mood stabilizers. Conclusion: It is likely that HF rTMS stimulation prior to ECT is a novel and simple way of reducing the ST, which is useful in certain groups of patients undergoing this important treatment modality.

Keywords

• ECT
• Seizure threshold
• TMS