Ictal EEG patterns in epilepsy with centro-temporal spikes.

PURPOSE To describe the EEG pattern of seizures in patients with benign childhood epilepsy with centro-temporal spikes (BCECTS). METHODS The clinical and EEG data of 701 BCECTS patients with at least a 3 years follow-up were reviewed from 10 epilepsy centers. RESULTS Thirty-four seizures were recorded in 30 patients. Four different ictal EEG patterns (A-D) were identified. The most frequent (pattern A) was characterized by low voltage activity of fast rhythmic spikes, increasing in amplitude and decreasing in frequency, and occurred in 14 children. Pattern B (six patients) was constituted by a discharge of spikes intermixed with sharp waves increasing in frequency and amplitude. Pattern C (seven children) consisted of monomorphic theta which progressively formed a discharge increasing in amplitude and decreasing in frequency. Pattern D (5 children) was characterized by a initial focal depression of the electrical activity, followed by one of the three above described patterns. In 21 out of 28 children, the initial ictal pattern, altered from one pattern to another one. No clinical or EEG feature was predictive of a specific ictal pattern. DISCUSSION We failed to identify a unique ictal EEG pattern in our patients with BCECTS. The occurrence of per-ictal features, e.g., initial EEG depression or post-ictal slowing, is common and should not be interpreted with prejudice. Alteration of ictal EEG pattern from one to another is not in conflict with the diagnosis of BCECTS.