Seizures triggered by video games, though rare, could be more common among certain players than previously thought, a new Seattle-based study indicates.
Physicians at Children's Hospital and the University of Washington analyzed 10 local cases in the past three years and 25 others reported elsewhere during a longer period. Fewer than half had had previous seizures from any cause or had relatives with seizure disorders.
"Video games are safe for the vast majority of people, but this is a phenomenon that occurs," said Dr. William Graf, director of the study. "In a community of this size, we will see these on a regular basis."
Graf said video games "do not cause normal people to develop a seizure disorder." But he said their rapidly flashing lights can turn up previously undetected disorders in children and adults.
Experts estimate 1 in 10,000 may be susceptible to seizures triggered by flashing or flickering lights.
The Children's Hospital study is believed to be the first to analyze video-game-related seizures, which have been increasingly reported in recent years. The study is reported in this month's edition of medical journal Pediatrics, released today.
Graf, a Children's neurologist and assistant professor of pediatrics at the University of Washington, said almost all of the seizures were over in four minutes or less and there is no evidence such episodes cause significant brain damage. All but two of the patients were teenagers or younger and most were boys.
Examinations of the Seattle-area patients and review of the other cases showed the patients were extremely sensitive to repetitive, high-intensity, multi-colored or white flashes; rapid changes in game scenes; line patterns and rolling or flickering images. Graf said 15 to 20 flashes per second especially seemed to set off the seizures.
Fatigue was also a major factor. Graf said some of the youngsters played the games three hours a day.
Of the 35, eight of the patients had had occasional seizures unrelated to video games; four had had fever-related convulsions and two had relatives with epilepsy.
Graf said two-thirds of the video-game-related seizures involved the entire brain. Seizure symptoms included blurred vision, dizziness, headache, jerking of the hand, temporary vision loss and unconsciousness.
Graf said more study needs to be done of those who have milder symptoms such as headaches, nausea and dizziness. One 18-year-old, for example, simply became very nauseated when looking at a video screen but did not have a seizure. Brain wave tests showed he was very sensitive to light stimulation, Graf said.
Simply not playing the games stopped the seizures in most of the patients, Graf said.
He said parents of children who have not had seizures should not worry about the seizures.
"I think they should allow kids to play with moderation, probably limited to one to two hours a day," said Graf.
Nintendo of America, based in Redmond, last year was held not liable for the effects of an epileptic seizure suffered in 1988 by a Michigan woman. A similar suit is pending in Texas.
Last year, Nintendo, the world's largest video-game maker, began placing notices on its games warning epileptics they could suffer seizures from playing the games.