Midline spike discharges: clinical and EEG correlates.

Thirty-four tracings in 32 patients had spike discharges recorded at Cz and Pz electrodes. Midline spikes showed strong correlations with clinical seizures; 91% had epileptic seizures of diverse types. Over two-thirds of the patients were neurologically impaired. Midline spikes most probably originate from discharging lesions of the mesial or paramedian region of the cerebral cortex.