Photoparoxysmal discharges among patients investigated after a single seizure.

EEG records of 408 consecutive patients, after a single epileptic seizure, were examined for evidence of a paroxysmal response to photic stimulation (PPD). 6.4% of the patients had PPD, a percentage slightly, but not significantly, higher than the 5.9% found on examining EEG records of 3161 clearly diagnosed epileptic patients who were routinely investigated at the same department over the same period. The observation in this study therefore suggests that a single epileptic seizure in a patient, like clearly established epilepsy, is associated with increased cerebral neuronal excitability as reflected by the PPD.