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According to Italian researchers, seizures caused by flashing video games and television shows can be minimized by using higher-frequency display rates. Such seizures affect about 10% of epilepsy sufferers between the ages of 7 and 19. In December, Pokomon, a popular Japanese television show with brightly flashing scenes, induced blackouts and epileptic seizures in more than 700 young victims, many of whom required hospitalization.

United Press International science writer Lidia Wasowisc reported on March 23 that a group of Italian researchers has determined that the low-frequency frame rate of typical video displays is primarily to blame for the seizures. Televisions in the US and Japan operate at an interlaced-field rate of 60 Hz, which translates to 30 frames per second (fps). European televisions run even slower: 50 Hz fields or 25 fps. Tests conducted by the researchers at both of these low rates and at a higher experimental rate indicate that the slower rates are more likely to cause problems. So is the viewer's proximity to the screen.

Led by Dr. Federico Vigevano of Bambino Gesu Children's Hospital in Rome, the researchers experimented on 30 volunteers with a sensitivity to television or video games. Electroencephalograms---maps of the brain's electrical activity---showed a higher incidence of seizure indicators among users of the lower-frequency devices. More than half the participants showed such signs using 50 Hz screens. In addition, there was a correlation with the user's distance from the display: Indications of seizure were more frequent the closer the user sat to the screen. A 100 Hz display used for comparison caused only one sign of a reaction, and there was no relationship with distance using the higher-frequency device.

If this study is correct, the implication is that computer monitors with high scan rates---which includes almost all such devices built in the past decade---pose little or no danger to susceptible people. Dr. Vigevano hopes his research can help prevent recurrences of the Pokomon incident. "We can use this information to help ensure that as few children as possible suffer adverse reactions to such common pastimes as watching TV or playing video games," he says.