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- Television programs have come under stricter regulation
in Great Britain and Japan after causing seizures in children. The illness,
a form of epilepsy known as photosensitivity, is triggered by the flashing
lights and quickly alternating shots found in many shows and commercials.
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- But while researchers have long known that bright, regular
flares can provoke epileptic episodes, photosensitivity has gained a higher
profile within the last 20 years as new triggers for the illness crop up
with each new piece of media technology that comes along. Indeed, an increase
in the number of stimuli--anything from fluorescent lighting to video and
virtual reality games--has led to debate as to whether measures similar
to those adopted in the UK should be enforced in the United States.
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- Trigger Happy
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- Epileptic seizures can occur when quick flashes of light
cause neurons to fire up and produce abnormal signals within the brain.
These flashes may come from almost any source.
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- Even seemingly benign scenes, such as sunlight reflecting
off of waves, for example, may trigger episodes. The strobe effect caused
by light passing between buildings and telephone poles and the blinking
of ambulances and fire trucks can provoke attacks. Flashing television
and video game screens can yield similar results.Indeed, what these settings
have in common is their regular and swift movement from darkness to brightness.
These bursts of light occur with a speed and frequency that does not give
the eyes (or anything else) much time to adjust, let alone to process the
image. Often, they bewilder even people who do not suffer from epilepsy.
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- Light Regulation
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- Professor Graham Harding of Britain's Aston University,
the world's foremost authority on photosensitivity, is one of the people
behind the UK's push to regulate television and commercials. Harding has
set out guidelines that include warnings for editors and game designers
against centering bars or black and white patterns on screens. He includes
information on the number of frames of contrast that must follow one another
and the patterns that most often produce epileptic seizures. Red, he notes,
is especially provocative, as are oscillating bars or grating in highly
contrasting colors (for instance, black and white).
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- But Harding also suggests that people who may suffer
from photosensitivity may help themselves by simply backing away from the
television set. Sitting too close causes problems: The hundreds of cycling
tiny bands that make up the TV picture only become perceptible at distances
of less than 1 meter (3 1/2 feet).
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- Rage Against the Machine
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- Indeed, it may fall to those with photosensitivity to
help themselves, because no attempt has generally been made to minimize
blinking lights and jarring video flashes. Indeed, these effects have only
become more widespread and fashionable in recent years.
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- Designers, programmers, and video editors have even been
choosing these effects in a deliberate attempt to cause disorientation.
After all, many people enjoy strobes in nightclubs, which are designed
to dazzle and heighten confusion. The lighting in amusement park rides
and casino marquees also produces similar effects.But while these displays
are supposed to be fun and exciting, the new sophistication and scope of
technology has triggered reactions in people--epileptics and non-epileptics
alike--that no one ever anticipated.
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- In addition to the widely reported "cartoon illness"
that provoked epileptic seizures in 685 Japanese children in 1997, shaky
camera work in the recent hit movie Blair Witch Project has caused many
people to vomit after becoming nauseous and dizzy. Similar symptoms have
also plagued fans of the computer game Doom. These problems arise because
the brain has difficulty adjusting to the game environment. The game Doom,
for instance, which puts players through bewildering and colorful three-dimensional
battles, shifts its display just slightly more slowly than the speed at
which the brain would perceive such objects in a similar situation in real
life.
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- The difference between the game and real life is that
in a game you don't really move. The pictures adjust so that you feel like
you are spinning around. But the pictures create this illusion slightly
more slowly than the same experience would occur if it were real. When
a player emerges from a Doom marathon, this slow adjustment rate (the "virtual
rate") is thrown into conflict with the real rate of the real world.
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- When a person stops playing the game, the result is akin
to motion sickness; the difference in speed causes vision to blur and even
makes some people throw up, all because the brain has become confused in
its reactions.
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- A Safe Distance
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- New technologies and new media become more sophisticated
and widespread every day, but little time has been spent considering the
possible effects these gadgets and games may have on people--with epilepsy
and without. Few take time to consider the impact of fluorescent lights
or flashing bulbs on those around them.
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- And those with photosensitive epilepsy bear most of the
brunt. With products springing up every day, they must approach every new
television commercial, movie, and computer program with caution.
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- Aug.1999 @ 1999 by Medscape Inc. All rights reserved.
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- Mindy Hung is a staff member at Medscape Professional.
She has also written for the Winnipeg Free Press and Salon.
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