A study of the effect of color photostimulation from a cathode-ray tube (CRT) display on photosensitive patients: the effect of alternating red-cyan flicker stimulation.
OBJECTIVE
In an attempt to establish evidence for developing better guidelines for the production of animation programs that would not induce photosensitive seizures in Japan, we evaluated the effects of red flicker, alternating red/cyan (complementary color to red) flicker stimuli, and of contrast between the red and cyan frames from a cathode-ray tube (CRT) display in photosensitive patients.


METHODS
We studied 35 photosensitive patients. They were exposed to seven types of flicker. The first three types were alternating red/cyan flicker (R/C) with the luminance of cyan set at three different levels, high, equal, and low luminance (65, 20, and 16 cd/m2, respectively) relative to the red (20 cd/m2). The following four types were red, cyan, yellow, and magenta flicker stimuli. EEGs were recorded while the patients watched these stimuli on a CRT display.


RESULTS
Rates of photoparoxysmal response (PPR) provocation were 11.4, 13.7, and 14.0% with high-, no- and low-contrast R/C flicker, respectively, and 3.7% with red flicker. The differences between red and each of the other R/C flicker stimuli were all statistically significant (p<0.05, 0.01, 0.01). No significant differences were found between the effects by each of the three levels of contrast in alternating R/C flicker (p > 0.05).


CONCLUSIONS
These findings suggest that alternating R/C flicker is more provocative than simple red flicker, and that contrast between frames of different colors may play some role in the effects of alternating flicker stimuli from a CRT display in photosensitive patients. Therefore, caution against the use of the combination of red and cyan, in addition to the red flicker stimulus, should be included in any guidelines drawn up to prevent photosensitive seizures.
Shirakawa
S
S
Department of Pediatrics, Tokyo Women's Medical University, Tokyo, Japan.
Funatsuka
M
M
Osawa
M
M
Fujita
M
M
Oguni
H
H
D000293:Adolescent; D000328:Adult; D002359:Cartoons as Topic; D002648:Child; D003116:Color; D003626:Data Display / Q000009:adverse effects / Q000706:statistics & numerical data*; D004569:Electroencephalography / Q000706:statistics & numerical data; D020195:Epilepsy, Reflex / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D017408:Guidelines as Topic / Q000592:standards; D006801:Humans; D007564:Japan; D008027:Light / Q000009:adverse effects; D008297:Male; D010775:Photic Stimulation / Q000009:adverse effects / Q000379:methods*; D015203:Reproducibility of Results; D013690:Television / Q000592:standards