Shaking, sweating and swooning are par for the course among the passionate young fans of the "Twilight" series. But reports that a scene in "Breaking Dawn" has been sparking seizures in theaters nationwide has epilepsy experts on the alert and parents thinking twice about letting their kids see the movie.
Officials at the Maryland-based Epilepsy Foundation issued a warning this week to their nearly 11,000 followers on Facebook, saying people prone to certain types of seizures might want to skip the film, which has been the top-grossing movie in the country for two weeks straight.
"If you were parents of a child with epilepsy, you would not send your child to the movie," says Mimi Carter, the foundation's director of communications. "Why would you risk it?"
There have been at least nine reported instances of people suffering seizures during "Breaking Dawn," the latest installment in the teen vampire series. The trigger seems to be a particularly intense birth scene that involves a strobe effect with flashes of red, white and black light.
In one widely reported instance, a California man at the theater with his girlfriend began to convulse during the graphic scene.
According to CBS Sacramento, paramedics rushed Brandon Gephart to the emergency room after he was "convulsing, snorting, trying to breathe." Gephart remembered nothing of the attack, but his girlfriend, Kelly Bauman, told reporters, "He scared me big time."
In another instance, a woman who took her daughters to see the movie in Oregon starting feeling "strange" during the birth scene.
I "[s]tarted feeling sick to my stomach, like I was going to be sick," Tina Goss told television station KATU in Portland. "Really hot, really sweaty, like on the verge of vomiting."
Goss told reporters she wasn't coherent again until arriving at a hospital. "My hands were completely blue for like two to three hours," she said. "The next day, I was so lethargic I felt like I'd, you know, like ran eight marathons."
No instances have been reported in Maryland. But others have occurred in Maine, Utah, Massachusetts and Canada.
Many more people say they have gotten sick during the movie — for reasons that have nothing to do with epilepsy. On Twitter, for instance, dozens of teens say they got queasy and even vomited or fainted during the movie's grislier interludes, which include a fair amount of blood and gore.
A retired physician in California, Zach Pine, began documenting cases on a website after his 18-year-old son, who had never had a seizure, suffered one during the movie. He lists nine reported instances on his Google page.
People susceptible to this sort of attack suffer from what's known as photosensitivity, a stimulus-induced seizure disorder.
While epilepsy is relatively uncommon in the population — about 3 million Americans have it — photosensitivity is even rarer, occurring in just 3 percent of those with epilepsy.
According to Dr. Tricia Ting, an assistant professor of neurology at University of Maryland School of Medicine, people with this disorder often don't realize they have it until they suffer a seizure. "They may have gone their whole lives without having a seizure, but in this circumstance, when presented with a flickering light, it can induce their first seizure."
A seizure trigger for a photosensitive person can be any number of things — strobe flashes as in the movie, driving past a repetitive pattern like a picket fence, watching sunlight flicker through some trees. And the seizure itself could be quite noticeable, with convulsions, or undetectable, with a person simply staring or seeming unresponsive.
"The stimulus triggers … an abnormal electrical discharge in the brain," Ting says. "That spark can lead to an electrical storm, which is a full seizure."
Though "very upsetting and disturbing," Ting says, these types of seizures are typically not life-threatening.
A well-known instance of a photosensitive reaction happened in Japan in 1997, when nearly 700 children were hospitalized after suffering seizures while watching the Pokemon cartoon on TV.
Kanye West's video for "All of the Light" comes with a warning, saying it could trigger seizures and that "viewer discretion is advised."
The phenomenon has also been known to occur in people playing video games.
Jessica Solodar, a Newton, Mass., mother, began blogging and trying to raise awareness about the problem after her daughter, Alice, suffered a seizure while playing a game.
"It takes an event like this 'Twilight' movie to get people to even consider the fact that we have a public health problem that is much more extensive than people realize," she says.
Solodar said Alice, who is 18 now, had, like many teenagers, wanted to go see "Breaking Dawn," but doesn't want to go now that she's heard about the seizures. "She'd rather not take any chances," she said.
The film's production company and American distributor, Summit Entertainment, declined to comment on the reported seizures.
Though Ting and epilepsy experts advise anyone prone to photosensitivity to skip the film, they have some advice for those who go anyway and might begin to feel ill.
"If people are seeing the film and they start to feel funny, they can stop that by not continuing to look at the screen," Ting says, adding that closing one's eyes might not be enough. "They need to block it with their hands. You really have to cover it completely."
Baltimore Sun reporter Michael Sragow contributed to this article.