Benjamin G. Zifkin and Yushi Inoue
From Epilepsia, Volume 45 Issue s1 Page 27-29 January 2004. doi:10.1111/j.0013-9580.2004.451005.x
Visual reflex seizures induced by complex stimuli may be triggered by patterned and flashing displays that are now ubiquitous. The seizures may be clinically generalized, but unilateral and bilateral myoclonic attacks also may be triggered, especially in patients with juvenile myoclonic epilepsy, and recently, clearly focal reflex occipital lobe seizures have been described. Some seizure-triggering properties of video displays can be identified, such as perceived brightness, pattern, flicker frequency, and color. Knowledge of these is useful in planning individual treatment and in designing regulations for screen content of television broadcasts or for other video displays. Some subjects will also be sensitive to cognitive or action-programming activation, especially when playing video games, and this can increase the chance of seizure triggering. Nonspecific factors such as sleep deprivation, prolonged exposure, and drug or alcohol use also may play a role in reflex seizure occurrence.
All of human society is increasingly likely to come into contact with visual stimuli that can trigger epileptic seizures in susceptible individuals. Computers, television screens, videogames, and other video displays are inescapable in education, work, and entertainment. Other patterned and flashing light displays are part of everyday life as direction or warning signs, advertising, entertainment, and other forms of information: these technologies also have spread to developing countries. The sources of visual stimulation have been described elsewhere in this volume.
From the EEG era, photosensitivity was identified by the response to stroboscopic white flicker (intermittent photic stimulation: IPS) in the EEG laboratory. Flicker sensitivity is usual in patients with different types of seizures induced by visual stimuli, but subtypes in which patients are reproducibly sensitive to more complex stimuli can be distinguished. These stimuli usually add elements of pattern, color, flicker, or movement, often to the inherent flicker stimulation of displays such as domestic television (TV) screens. Other intrinsic factors not related to typical visual stimuli but adding to the seizure-generating properties of stimuli such as videogames include cognitive activity, thinking with action programming, and reading. Kasteleijn-Nolst Trenit
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