Latest on Epilepsy

20-8-2009 | Photosensitive Analaysis Tool for Web Developers

20 August 2009
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Researchers in Milwaukee, Wisconsin have released a free software tool that could help Web surfers susceptible to certain seizures.

Photosensitive Epilepsy (PSE) describes a sensitivity to flashing or flickering lights, at a certain frequency, as well as certain geometric patterns and glare. About 3-5% of people with epilepsy are photosensitive. The condition gained prominence in 1997 when more than 800 Japanese children were hospitalized after viewing a cartoon. More recently the 2012 London Olympics logo had to be withdrawn because a large number of people experienced seizures on being exposed to the flashing image.

Television directors, video-game makers and others now test their content to make sure it doesn't reach seizure-inducing thresholds. Web developers, though, didn't have simple ways to run such tests. Researchers at the University of Wisconsin-Madison set out to change that.

"On the Web you really never know what's going to pop up on the screen until it does, and one second later you could be having a seizure," said Gregg Vanderheiden, the centre's director. Web developers can use the Photosensitive Epilepsy Analysis Tool, or PEAT, to determine how fast an image blinks, for example, and let developers know whether it poses a seizure risk. Content that doesn't pass the test isn't always risky. Researchers say flashy content that doesn't fill at least 10 percent of a screen isn't a danger.

Robert Fisher, the director of the Stanford Epilepsy Centre in Palo Alto, California, said he knew of "dozens of clips" on YouTube that can provoke seizures. He advises viewers with epilepsy to avoid any sites where content blinks and flashes and to be ready to avert their eyes if necessary.


Dr. Giuseppe Erba, a neurology professor at the University of Rochester in New York, said Web developers now have a responsibility to use the testing tool to make sure the content they produce is safe.

Vanderheiden said his next priority is to create tools that give epileptics control over what is shown, so they wouldn't have to rely on Web developers to run PEAT. One option is a software tool that could detect and disable all blinking content, he said. Another might dim the contrast on the screen to mute the effect of changing colours.

Free PEAT software for Web Developers is available for download at http://trace.wisc.edu/peat/

It should be noted that overall, the condition of photosensitive epilepsy is relatively rare and should not lead to undue restrictions for people with epilepsy as a group.
 

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