Abstract
We reported a case of an eight-year-old boy with CEOP. His parents and sibling were in good health. There was no family history of epileptic and neurological disease. He had his first attack of unconsciousness with fixation of eye movement for a few minutes at the age of 7 years. After six months, he experienced attacks of vomiting followed by loss of consciousness and elementary visual hallucinations consisting of red and blue colors. Sometimes he complained of contraction of visual field for 10 to 20 seconds, as if a curtain had fallen following the visual hallucination of a bright light spot. At the age of eight years, he was admitted to our hospital for evaluation and therapy. Investigations included neurological examination, IQ, CT findings were normal. Visual evoked potential revealed more reduced amplitude in the left side than in the right. The EEG findings during the waking state showed continuous bilateral 1-2 c/s spike and wave complex discharges in occipital and posterior temporal areas. These discharges were immediately suppressed by eyes-opening in an illuminated room, but not in a dark room. However, during the light sleep stage, diffuse irregular spike and wave discharges appeared frequently with left side dominance. From the clinico-electrophysiological findings we diagnosed him as CEOP.
In order to investigate the changes of the occipital spike and wave discharges by photic stimulation, we administered intermittent photic stimulation (IPS) for 10 seconds at each frequency between 1-30 flashes/sec (f/s) in a dark room. These discharges were suppressed immediately after stimulation with 9-13 f/s, and there was a delay of two seconds before suppression when stimulation with 6-8 f/s was given. They were suppressed by the photic stimulation from the frontal direction but not from the lateral direction.
From the EEG and clinical findings, we conclude that the suppressing mechanism induced by photic stimulation was related to the centroencephalic system.
