Friday, March 7, 2008

Flickers


As a parent of a child with epilepsy, I have heard many times that watching television can trigger a seizure. Up until about a year ago, Ashley was never really interested in television, but she now knows when her favorite shows come on and will request to watch them. Because of this newfound interest, I have been a little concerned about her seizures. I don’t believe watching TV has ever triggered one of her seizures, but I still worry. So, when I saw a news article about a music video by Gnarls Barkley being blocked from play by MTV for the very reason that it could trigger a seizure, I decided to do a little research.

According to the article about Gnarls Barkley, the music video failed the ‘Harding Test’, a test of television seizure guidelines. Graham Harding, pictured above, is an authority on photosensitive epilepsy. He developed the Harding flash and pattern analyser, which the Independent Television Commission adopted in 1994 and which is still the standard test to guard against epilepsy-inducing scenes.

Graham Harding, in conjunction with Cambridge University, developed the HardingFPA product, a TV flash and pattern analyzer. According to Professor Harding’s website, the FPA product “analyses material frame-by-frame, in real time, directly from most video sources. It verifies compliance with the ITC Guidelines on Flashing Images and Regular Patterns in Television, warns of any sequences likely to precipitate epileptic seizures (PSE), and promotes a safer television viewing environment.”

I also found some information on Photosensitive Epilepsy (PSE). “Photosensitivity is sensitivity to flickering or intermittent light stimulation and visual patterns. It affects approximately one in four thousand people. A number of people have this sensitivity but have not yet had a seizure and therefore have not been diagnosed with the condition of photosensitive epilepsy. The most common trigger for photosensitive epilepsy is the domestic television set. Almost fifty percent of patients are sensitive to the 50Hz flicker of television, and some seventy five percent of patients are sensitive to the 25 Hz flicker from the line raster which can be observed with close viewing. The onset of photosensitive epilepsy in an individual occurs typically around the time of puberty; in the age group 7 to 20 years the condition is five times as common as in the general population. Three quarters of patients remain photosensitive for life.”

So, does this newfound information make me feel better or worse about Ashley’s interest in TV? I’m not sure. But, it will make me more observant, especially because PSE often begins around the time of puberty. Now I need to find out if PSE results in specific types of seizures so I will know what to look for while observing Ashley. If any of my readers have additional information, please share!!

4 comments:

Marla said...

Very interesting. We recently completed a 72 hour EEG which showed no seizure activity in our daughter. Seizures can be so hard to detect. Now, she is diagnosed with CVS. I know that lights really bother her and have also wondered about the television.

Ashley's Mom said...

Marla, what was the 72 hour eeg like? One has been suggested for my Ashley, but I can't imagine how she could stay hooked up for that long - 72 minutes probably wouldn't even work!

Marla said...

I am going to e mail you about it right now. :)

MMC said...

We did a ... 3 day (?) EEG once. That was interesting. It was done as an inpatient, she couldn't leave the hospital room but she could move around it as long as she stayed within range of the camera.

In addition to the EEG machine, itself, they have keep a camera trained on the person (the drs can manually make the camera move to follow the person as they move) so that when they 'catch' a seizure on the EEG they can also observe what it looks like at the same time. We were trying to pinpoint the location where her seizures came from. No such luck ... but she seized almost constantly the night before they hooked her up to the damm thing. And, of course, she started again once they unhooked it. And the glue ... just about impossible to get out of her hair. We're gonna have fun, fun, fun ...