Shortening the pulse width to 0.3 millisecond holds neurophysiological and clinical promise of making electroconvulsive therapy (ECT) safer by reducing cognitive adverse effects. The exclusive effects of pulse width on autobiographical and subjective memory are largely unstudied. The aim was to principally investigate during the acute ECT course and at 3 months after ECT autobiographical and subjective memory effects of 0.3-millisecond ultrabrief and 1-millisecond brief-pulse ECT.
Patient with severe depression were randomized to 1-millisecond brief-pulse (n = 20) or 0.3-millisecond ultrabrief-pulse (n = 20) right unilateral ECT, both at 6 times the threshold stimulus dose given thrice weekly. Autobiographical Memory Interview (Kopelman) and Squire Subjective Memory Questionnaire were administered at baseline, after 8 sessions, end of the acute course, and 3 months later.
Early adult semantic memory worsened significantly over time with brief-pulse compared with ultrabrief ECT: F3,88 = 2.60, P = 0.05. There was a significant decline in brief-pulse treatment vis-à-vis a significant improvement with ultrabrief-pulse treatment with childhood semantic memory (P = 0.022), early adult semantic (P = 0.03), and recent semantic memory (P = 0.018) only at 24 hours after the eighth ECT treatment.
Clinically meaningful and significant improvement in semantic autobiographical memory occurred in ultrabrief treatment vis-à-vis brief-pulse ECT after 8 treatments. Ultrabrief treatment offered a small but significant advantage over 1-millisecond brief-pulse high-dose right unilateral ECT with early adult semantic autobiographical memory, which persisted up to 3 months.