Reliable Change Indices and Minimum Detectable Change for the Montreal Cognitive Assessment in Electroconvulsive Therapy for Depression

Abstract

Objective The Montreal Cognitive Assessment (MoCA) is a commonly used brief cognitive screening tool for monitoring adverse cognitive effects of electroconvulsive therapy (ECT). The aim of this study was to examine three statistical methods for detecting reliable change in the MoCA following ECT. Methods In a prospective cohort study, 47 patients (mean age 55.2 [SD = 12.8], 59.6% female) with unipolar or bipolar depression treated with an acute course of brief-pulse ECT (72.3% right unilateral) and 47 depressed controls without ECT exposure were tested on the MoCA at baseline and retested at comparable time intervals. ECT patients' performance was also compared to published normative data from a community-based sample of older adults. We calculated proportions of ECT patients remaining stable, declining, and improving following ECT using practice-corrected reliable change index, standardized regression-based formulas, and minimum detectable change cutoff of ±4 MoCA points. Results Using the three methods, 72.3%–78.7% of ECT patients remained stable, 17.0%–23.4% declined, and 4.3% improved in MoCA performance following ECT compared to the two control groups. Conclusions All three methods yield consistent estimates of reliable change in MoCA scores from pre– to post–brief-pulse ECT. The minimum detectable change approach may be the most efficient and accessible method of detecting change due to simplicity of calculation.