Seizure Threshold at the Start of ECT. An analysis of covariance was conducted on log-transformed (base10) seizure threshold values, with pulse width and electrode placement conditions and their interaction as between-subject terms and age as a covariate. Seizure threshold was approximately three times higher in patients treated with a brief pulse compared to an ultrabrief pulse stimulus (P<0.001, F = 85.8, df = 1, 85). Seizure threshold was approximately two times higher in patients treated with bilateral compared to right unilateral ECT (P<0.001, F = 32.5, df = 1, 85). The relationship between age and seizure threshold was marginal (P=0.073, F = 3.3, df = 1, 85).