Electroconvulsive therapy (ECT) is the most effective therapy for patients with treatment-resistant depression; however, some patients do not respond or relapse in a short time. Electroconvulsive therapy stimulus parameters may be related to the outcome. We carried out a retrospective study review to investigate various ECT parameters in relation to the outcome, clinical variables, and pharmacological treatments. Our aim was to understand which factors could be considered putative seizure quality markers and which are relevant to clinical practice.
Two physicians evaluated the seizure length, the postictal suppression index, the wave amplitude, tachycardia, and hemispheric brain wave synchronicity in a double-blind manner for 45 treatment-resistant depression patients receiving ECT.
The analysis showed a significant association between the outcome and the ECT seizure quality measured by the parameters (P = 9.9 × 10−5). Among patients with poor-quality seizures, 61.5% relapsed after approximately 1 month from the last ECT session. Particularly, there was an association between higher symptomatology decrease and higher quality of hemispheric brain wave synchronicity (P = 5.0 × 10−6), as well as a higher wave amplitude (P = 0.01).
Our results confirm that ECT seizure quality was strongly correlated with the decrease of depressive symptomatology.