Lateral hemifield flickering pattern stimulation in a patient with pattern-sensitive epilepsy

Provocative effects of paroxysmal discharges (PDs) by lateral hemifield pattern stimuli were studied in a 24-year-old female patient with pattern-sensitive epilepsy. Provocation of focal posterior PDs in the contralateral hemisphere became more evident by adding 15/s flicker to the lateral hemifield pattern (hemifield flickering pattern) stimuli than by stimulus with the lateral hemifield grate pattern or with the lateral hemifield dot pattern alone. Such a finding was also observed when lateral hemifield flickering pattern stimuli were given to each eye. In this patient, left hemifield flickering pattern stimuli were slightly more effective than right hemifield stimuli in provoking the corresponding focal posterior PDs. It is suggested that lateral hemifield flickering pattern stimuli might be useful for a precise EEG examination of the posterior regions of the brain in patients with pattern-sensitive epilepsy and allied conditions.