Diagnosis[edit]
Diagnosis may be made by noting the correlation between exposure to specific visual stimuli and seizure activity. More precise investigation can be carried out by combining an EEG with a device producing intermittent photic stimulation (IPS). The IPS device produces specific types of stimuli that can be controlled and adjusted with precision. The testing physician adjusts the IPS device and looks for characteristic anomalies in the EEG, such as photoparoxysmal response (PPR), that are consistent with PSE and/or may herald the onset of seizure activity. The testing is halted before a seizure actually occurs.
Sometimes diagnostic indicators consistent with PSE can be found through provocative testing with IPS, and yet no seizures may ever occur in real-life situations. Many people will show PSE-like abnormalities in brain activity with sufficiently aggressive stimulation, but they never experience seizures and are not considered to have PSE.
Treatment and prognosis[edit]
No cure is available for PSE, although the sensitivity of some people may diminish over time. Medical treatment is available to reduce sensitivity, with sodium valproate being commonly prescribed. Patients can also learn to avoid situations in which they might be exposed to stimuli that trigger seizures and/or take steps to diminish their sensitivity (as by covering one eye) if they are unavoidably exposed. These actions together can reduce the risk of seizures to almost zero for many PSE patients.
Society and culture[edit]
Games[edit]
The first case of epileptiform seizures related to a video game was reported in 1981.[10] Since then, "many cases of seizures triggered by video games were reported, not only in photosensitive, but also in nonphotosensitive children and adolescents with epilepsy... Specific preventive measures concerning the physical characteristics of images included in commercially available video games (flash rate, choice of colours, patterns, and contrast) can lead in the future to a clear decrease of this problem."[10] Risks can be reduced through measures such as keeping a safe distance away from the screen (at least 2 meters).[10]
While computer displays in general present very little risk of producing seizures in PSE patients (much less risk than that presented by television sets), video games with rapidly changing images or highly regular patterns can produce seizures, and video games have increased in importance as triggers as they have become more common. Some people with no prior history of PSE may first experience a seizure while playing a video game. Often the sensitivity is very specific, e.g., it may be a specific scene in a specific game that causes seizures, and not any other scenes. Despite this, there are questions on the dangers of this, and calls for testing all video games for causing PSE.[11]
Web design[edit]
As with video games, rapidly changing images or highly regular patterns such as flashing banner ads or irregular fonts can trigger seizures in people with photosensitive epilepsy. Two sets of guidelines exist to help web designers produce content that is safe for people with photosensitive epilepsy:
Public incidents[edit]
Photosensitive epilepsy was again brought to public attention in December 1997 when the Pokémon episode "Dennō Senshi Porygon" ("Cyber Soldier Porygon") was broadcast in Japan, showing a sequence of flickering images that triggered seizures simultaneously in hundreds of susceptible viewers (although 12,000 children reported symptoms which may be attributable to mass hysteria).[15][16]
In March 1997, the 25th episode of an anime series called YAT Anshin! Uchū Ryokō caused a similar incident, when a reported four children were taken to hospitals by ambulances after viewing a scene with red and white flashing colours.[17]
In March 2008, the Anonymous group of hackers was claimed to be behind an attack on a forum for people with epilepsy.[18] The Anonymous hackers in turn blamed the Church of Scientology for the attacks, saying they were falsified to hurt Anonymous' image.[18] The attacks first consisted of GIF images flashing at high speeds that were hidden in discussion threads with innocuous-sounding titles. Later attacks redirected web browsers to a page with "a more complex image designed to trigger seizures in both photosensitive and pattern-sensitive epileptics."[19] The technology website Wired News considered it to be "possibly the first computer attack to inflict physical harm on the victims".[19]
An animated segment of a film promoting the 2012 Summer Olympics was blamed for triggering seizures in people with photosensitive epilepsy. The charity Epilepsy Action received telephone calls from people who had seizures after watching the film on television and online. In response, the London 2012 Olympic Committee removed the offending segment from its website.[20]
In December 2016, Newsweek journalist Kurt Eichenwald, who has epilepsy, reportedly had a seizure after an internet troll intentionally sent him a flashing GIF via Twitter.[21] Three months later, the user behind the GIF was arrested and charged with cyberstalking.[22]
The 2018 Pixar film Incredibles 2 contains scenes with flashing lights starting about an hour into the film, in which a villain called the Screenslaver hypnotizes other characters. After concerns over possible triggering of seizures due to this scene, theatres posted warnings for audiences with this condition.[23]
Cyberpunk 2077, a video game released in December 2020, contains a "braindance" sequence with red and white flashing lights which reportedly resembles the patterns produced by medical devices used to intentionally trigger seizures. Liana Ruppert, a journalist for Game Informer who has photosensitive epilepsy, experienced a grand mal seizure while reviewing the game days before its release.[24] After criticism from epilepsy advocacy groups that the game's disclaimers were insufficient, CD Projekt Red announced work on a fix[25] and later patched the effect to be less likely seizure-inducing.[26]