Mechanisms of video-game epilepsy

Purpose: We aimed to elucidate the mechanisms underlying video-game epilepsy by comparing the flicker- and spatial-frequency ranges over which photic and pattern stimulation elicited photoparoxysmal responses in two different populations: (a) 25 patients with a history of seizures experienced while playing video games; and (b) 25 age- and medication-matched controls with a history of photosensitive epilepsy, but no history of video-game seizures. Methods: Abnormality ranges were determined by measuring photoparoxysmal EEG abnormalities as a function of the flicker frequency of patterned and diffuse intermittent photic stimulation (IPS) and the spatial frequency of patterns on a raster display. Results: There was no significant difference between the groups in respect of the abnormality ranges elicited by patterned or diffuse IFS or by spatial patterns. When the groups were compared at one specific TPS frequency (similar to 50 Hz), however, the flicker frequency of European television displays, the video-game patients were significantly more likely to be sensitive. Conclusions: The results suggest that video-game seizures are a manifestation of photosensitive epilepsy. The increased sensitivity of video-game patients to IFS at 50 Hz indicates that display flicker may underlie video-game seizures. The similarity in photic- and pattern-stimulation ranges over which abnormalities are elicited in video-game patients and controls suggests that all patients with photosensitive epilepsy may be predisposed toward video-game-induced seizures. Photosensitivity screening should therefore include assessment by using both TPS at 50 Hz and patterns displayed on a television or monitor with a 50-Hz frame rate.