Visually determined high-frequency seizure activity.

The duration of high-frequency electroconvulsive therapy (ECT) seizure activity, the "spike seizure duration," was rated by two experienced clinicians from the paper EEG recording, along with total EEG seizure duration. The spike seizure duration, taken together with other seizure duration measurements, has shown differences between ECT methods of apparently different efficacy, such as unilateral and bilateral ECT. Close correspondence between the raters demonstrated high reliability for the determination of spike seizure duration, with interrater reliability kappa of 0.92 (p < 10(-6), although the raters employed different rules for selecting the end point.