The U.K. guidelines also adopted this regulation. GUIDELINES. Subsequently ... broadcast material for compliance with the TV guidelines is a laborious and ...
Epilepsia, 45(Suppl. 1):46–48, 2004 Blackwell Publishing, Inc. C International League Against Epilepsy
Regulations: What Next? Graham F. A. Harding and Takeo Takahashi Neurosciences Institute, Aston University, Birmingham, England; and Yaotome Clinic, Sendai, Japan
Summary: Television (TV) is the most provocative visual stimulus and evokes (first) seizures in susceptible children and adolescents, especially when flickering and patterned images are shown. This has led to the initiative to develop guidelines for broadcasters. The development of new types of TV screens will not remove the need for control of broadcast material. It could be argued that rather than protect the whole viewing audience by application of broadcasting guidelines, only those who are photosensitive should be protected. But maybe we should do
both, because most known sensitive patients will benefit from greater safety and will not be dependent on fashionable ideas by commercial broadcasters that are not (yet) familiar with the guidelines. No such guidelines exist for video material, electronic screen games, and the Internet. It would be wise to adopt the guidelines for video material and electronic screen games. Key Words: Photosensitive epilepsy—TV Guidelines—Flashpattern TV analysis—TV filter.
Television (TV) is known to be a common precipitant of photosensitive seizures. In Europe it is by far the most common precipitant; >60% of patients with photosensitive epilepsy experience their first seizure while watching TV (1). Although the TV monitor, whether used for broadcast material, video playback, or electronic screen games, is inherently a flickering medium (2); specific broadcast material is known to be especially provocative. The TV picture is made up of a series of frames that occur at a rate of either 25/s (PAL) or 30/s (NTSC). Rapidly changing material from one frame to the next therefore has the potential to produce temporal flicker (flashes) or spatial oscillations or reversal (alternating patterns). Because this type of material has been shown to provoke seizures (2), guidelines have been produced by the TV broadcasters in the U.K. to prevent transmission of this type of material. In 1997 the Pok´emon incident in Japan (3,4) demonstrated the danger of broadcasting unregulated material. The episode, screened in December 1997, contained periods in which long-wavelength red frames were alternated with blue frames. Six hundred eighty-five persons were admitted to hospital, and further studies have shown that 560 had had definite seizures; of these, 76% had not experienced a previous seizure (5). This particular type of stimulation, which is related to the phosphors of the TV monitor, caused the Japanese TV industry immediately to adopt guidelines similar to those in the U.K. and
specifically to warn of the dangers of long-wavelength red flicker. The U.K. guidelines also adopted this regulation. GUIDELINES Subsequently guidelines were revised (6) and refined, but all regulate flicker, pattern, and the use of longwavelength red. The adoption of guidelines is now under consideration in Italy, Russia, and has been followed by Disney and ABC in the United States. In general, the principles of guidelines are as follows: a. Flicker. Repetitive flashes of >3/s are not allowed. b. High-contrast patterns that alternate, reverse, or oscillate are not allowed if more than five repetitions are present on the screen. High-contrast stationary patterns are similarly controlled but are allowed to occupy a larger screen area. However, patterns that move smoothly across, into or out of the screen, are allowed. c. Flashes of long-wavelength red at >3/s are not to be used. In addition, clauses specify the amount of the screen that may be occupied by the flashes or patterns exceeding the guideline limits (typically