Study on Photo‐Pattern Sensitivity in Patients with Electronic Screen Game–Induced Seizures (ESGS): Effects of Spatial Resolution, Brightness, and Pattern Movement

Abstract

Summary: Purpose: With the ever‐increasing popularity of computers, electronic screen game–induced seizure (ESGS) is beginning to pose a serious social problem. To elucidate the pathophysiology of ESGS, with the ultimate goal of prevention, we have been studying photo‐pattern sensitivity in detail with a pattern‐stimulation test using a CRT (cathode ray tube) display. This method is referred to as the “CRT‐pattern test.” Methods: We studied 17 patients brought to our department for evaluation of ESGS. EEG responses were recorded during exposure to various patterns consisting of three elements: spatial resolution, brightness perception, and pattern‐movement recognition displayed on a CRT monitor. Photo‐paroxysmal response (PPR) frequencies were compiled for each stimulation. Results: PPR was induced by the CRT‐pattern test in nine of the 17 cases. In four cases, PPR induction was obtained only after introducing CRT‐pattern tests in addition to standard intermittent photic stimulation (IPS). The rate of PPR induction differed according to the type of pattern, spatial frequency, and pattern‐reversal frequency. However, neither the clarity of the edges of a pattern nor changes in the brightness of a pattern element had any effect on the rate of PPR induction. With the exception of a few subjects, the stimulation caused by pattern movement was not effective in eliciting PPR. Six cases in whom spatial resolution was involved showed occipital dominance in PPR provocation, and three in whom brightness perception and pattern movement recognition was involved showed frontal dominance. Conclusions: The CRT‐pattern test is useful for identifying patients with photosensitivity among patients considered to have incidental or nonphotosensitive seizures unresponsive to standard IPS. Patients with ESGS caused by photosensitivity can be divided into two groups: those with occipital dominance for PPR provocation, in whom spatial resolution is involved; and another group with frontal dominance, in whom brightness perception and pattern‐movement recognition (or possibly perception of colors) are involved.

Photic‐ and Pattern‐induced Seizures: A Review for the Epilepsy Foundation of America Working Group

“…Video display units (VDUs) should be less likely than TVs to provoke seizures, because VDUs tend to be smaller, less bright, usually refresh at 70 Hz, as opposed to 50 or 60 Hz, and they do not have the interlaced double raster scan that provides a flicker at half of the scan frequency (113). However, video display computer screens still can produce photic seizures in the sensitive subject (113). A PPR is to be expected among most patients who have a seizure while watching TV.…”

“…Photosensitive patients should avoid black‐and‐white checkered floor tiles or patterns, stripes, light through window vents, rotating ceiling fans, flashing lights, and sitting <3 m from a TV. Funatsuka and colleagues (113) recommended that pattern‐sensitive individuals avoid the following: (a) geometric patterns, especially stripes occupying much of the display; (b) fine patterns with spatial frequencies >2 cycles/degree; (c) frequencies ∼20 Hz with pattern‐reversal stimulation; (d) patterns with large differences in brightness; and (e) rapid pattern movements. The National Association of Commercial Broadcasters in Japan and Nippon Hoso Kyokai made recommendations for producers of animated programs.…”

Pattern‐sensitive Epilepsy: Electroclinical Characteristics, Natural History, and Delineation of the Epileptic Syndrome

“…Visual stimuli are by far the most common trigger of these reflex epilepsies (2,3). Either simple visual stimuli such as light or patterns (4,5) or complex visual excitations such as television or video games may trigger visually induced seizures in subjects with television‐ or video game–induced seizures (6,7).…”

Neural basis of photo/chromatic sensitivity in adolescence

“…Several lines of evidence suggest that photosensitivity (Jeavons et al, 1972; Panayiotopoulos et al, 1972; Harding et al, 1975), pattern sensitivity (Wilkins et al, 1979; Harding et al, 1994; Fylan & Harding, 1997; Funatsuka et al, 2001) and temporal frequency dependence (Harding et al, 1994; Harding & Harding, 1999) play important roles in the generation of PSE. Our previous study (Tobimatsu et al, 1999) demonstrated that PPR is more frequently observed in response to rapid B/R frame changes (temporal frequency, 12 Hz) compared with monochromatic changes in the patients with “Pokemon seizure.” No antagonistic relation exists between red and blue cone impulses in the primary visual cortex (V1) (Livingstone & Hubel, 1984), so B/R inputs result in maximal stimulation of the visual cortex.…”

“…Several lines of evidence suggest that photosensitivity Panayiotopoulos et al, 1972;Harding et al, 1975), pattern sensitivity (Wilkins et al, 1979;Fylan & Harding, 1997;Funatsuka et al, 2001) and temporal frequency dependence Harding & Harding, 1999) play important roles in the generation of PSE. Our previous study (Tobimatsu et al, 1999) demonstrated that PPR is more frequently observed in response to rapid B/R frame changes (temporal frequency, 12 Hz) compared with monochromatic changes in the patients with "Pokemon seizure."…”