ABSTRACT
On investigation, no neurological abnormalities were found and intelligence was normal. A computed tomography scan was normal. An EEG showed alpha activity, which was intermingled with sharp components; the alpha activity increased after hyperventilation. There were no spontaneous epileptiform discharges. Photic stimulation with flash frequencies between 2 and 60 Hz in the conditions eye closure, eyes closed and eyes open was performed; pattern stimulation with black and white striped patterns was tested; and the patient was asked to watch a 50-Hz television showing various programmes. Finally, a 70-Hz computer screen with scrolling text and graphic elements was used.
