University of Maryland

Harding Interview Transcript

During the initial development of PEAT, Trace Center Director Gregg Vanderheiden conducted a short interview with Dr. Graham Harding, who is a leading expert on photosensitive seizure disorders. The interview provides an introduction to photosensitive seizure disorders and outlines some of the basic features and design goals of the PEAT tool.

Vanderheiden: My name is Greg Vanderheiden. I’m a professor at the University of Wisconsin and director of the Trace R&D Center here at the University. With me is Dr. Graham Harding, a world expert on photosensitive epilepsy who is over here visiting to help us develop technologies to look at epilepsy and prevention of epilepsy in web content and computer displays. Dr. Harding, perhaps you could start by just explaining what photosensitive epilepsy really is?

Harding: Yes. Photosensitive epilepsy is a condition in which people have seizures or attacks or fits when they are presented with a visual stimulus. It’s not very common, whereas epilepsy is common, photosensitive epilepsy occurs in approximately 1 in 4000 of the population.

Vanderheiden: Is photosensitive epilepsy age-related?

Harding: It’s most common around puberty; so therefore, most individuals will have their first seizure between the age of about 7 and 15 years.

Vanderheiden: If you have a seizure, is it something to be really afraid of? Like, “Oh now I’ve had a seizure, so I’m going to have them all the time”?

Harding: There is no clear evidence in humans that one seizure makes you more likely to have another one.

Vanderheiden: If someone we know had a photosensitive seizure, what should we do?

Harding: The first thing to do is to put the person into the recovery position…the normal recovery position, mainly because you want to keep their airway clear so that should they vomit during the seizure, it does not block their airway. Other than that, the main thing is to make sure that there is nothing around on which they can injure themselves while they’re having the seizure. Other than that, you just watch.

Vanderheiden: You don’t try to hold them down or anything?

Harding: You don’t try to hold them down. You never try to force things between their teeth. Always remember that in a seizure, yes, because they’re going into a chronic phase, they may bite their tongue. Tongues heal, teeth don’t. If you push something between their teeth when they’re in a chronic phase, you will simply break their teeth. So, the main thing is to actually observe. It will be relatively short-lasting. The only time one has to be concerned (these are very rare with photosensitive seizures), is if the seizure starts going on for a long time; more than five minutes. Then, obviously, when you’ve got the person in a safe position, then that’s the time to call for medical help. In general, nearly all patients come out of the seizure. They will feel tired afterwards and will want to sleep, and that’s one of the typical signs that tell you it is a seizure.

Vanderheiden: And there’s no reason not to let them go to sleep?

Harding: No reason at all not to let them go to sleep.

Vanderheiden: So there are a number of simple things that people can do, and one of them would be; if they think that something might be a trigger, and they know they’re a photosensitive epileptic, they would just cover 1 eye. Are there other things that you might do?

Harding: They should view television in a well lit room from a distance of 2 meters or 8 feet and never go closer. They obviously should be careful when playing computer games, particularly if they’re playing computer games on a television.

Vanderheiden: Well, one of the reasons you’re here is that we’re looking at developing instrumentation to look at web content and computer screens etc to try to develop tools that could analyze content to detect these kinds of things so we don’t put them out if we can help it. This is based on the work you had done with Cambridge Research Systems on developing the analysis systems for television. Could you just briefly tell us a bit about that?

Harding: What we developed at Cambridge Research Systems was an automatic way of testing this material. It’s a computer-based system so that either online television broadcasts or recorded on tape television broadcasts can be played through the machine and the machine will recognize when any of these dangerous parameters occur. When there is white flashing (luminance flashes) occurring, when there are strong black and white patterns (particularly patterns which alternate backwards and forwards) occurring, if there is a very deep red color which is always dangerous particularly when presented on a television monitor because of the color of the phosphors. Each of these parameters can be automatically scored, and a warning can be issued immediately if it goes above a certain level.

Vanderheiden: Well thank you very much for coming over and helping us with this and taking the time out to record some of this and also to give a chance for people visiting the website to get a chance to meet you. You’ve done so much in this area. Thank you very much.

Harding: Thank you very much indeed.