Three electroconvulsive therapy (ECT) stimuli of increasing dosage were applied sequentially under one anesthesia to each of two patients. With each, the first produced intense electroencephalogram (EEG) seizure activity with a sharp endpoint but no motoric activity and little heart rate elevation. The second produced 15–21 s of tonic-clonic activity with negligible seizure activity on the EEG monitor and little heart rate increase. The third produced typical motoric, EEG, and heart rate signs of seizure. These observations indicate that the signs of high EEG amplitude, sharp EEG endpoint, distinct postictal suppression, and tonic-clonic activity can appear in seizures of questionable quality and weak generalization through the brain. Consequently, none of these characteristics by themselves indicate good quality or seizure generalization, and ECT monitoring is incomplete without considering all of them along with peak heart rate.