The Pokémon Episode that Triggered Seizures in 685 Viewers

March 26 was Purple Day or Epilepsy Awareness Day. I posted about a Photosensitive Epilepsy Analysis Tool (PEAT) for online video content on my LinkedIn, which turned into a discussion on that one Pokémon episode.

Photosensitive Epilepsy Analysis Tool

In light of Purple Day, let's sensitize ourselves about photosensitive seizure disorders and what we can do to make our web content safe and accessible: The Photosensitive Epilepsy Analysis Tool (PEAT) by Trace Center is a free and open-source tool designed to help creators identify potential seizure risks in their web content and software.

PEAT uses a specially developed analysis engine for web and computer applications, allowing you to assess if animations or videos in your content could trigger epileptic seizures.

It is highly recommended to review videos and animations, especially those with flashing lights or rapid transitions between dark and light backgrounds, to ensure they are safe for all users!

Computer Warrior Porygon

Turns out that we did not collectively fabulize about one episode triggering seizures in children. It actually happened, and it was Episode 38: Computer Warrior Porygon, first aired on December 16, 1997. And this is where I get to quote the most reliable resource for all Pokémon-related information, Bulbapedia:

The episode is infamous for resulting in many viewers suffering adverse health effects, including epileptic seizures, vomiting, irritated eyes, and other related symptoms, due to use of a flashing strobe effect upon its first and only airing. Because of that, this episode was never commercially released or re-broadcast anywhere in the world, and the show went on hiatus for four months.

Although it wasn’t exclusively children, there was a significantly higher incidence rate among 11 to 15-year-olds. With over 90% of the affected being from middle and high school age ranges, we can skip the causation-correlation question for this one.

According to a survey by Japan's Fire and Disaster Management Agency [Shōbōchō], 685 viewers - 310 male and 375 female - were taken to hospitals by ambulances. Of these, 208 were admitted to said hospitals, including three who were admitted while unconscious.

And can I just say that it’s kinda weird that Wikipedia has the whole 4-second clip, in original speed at the top of the page?

After this episode, the animation studio dropped the strobe effects from Pikachu's thunderbolt. For years following the incident, a disclaimer was broadcast at the beginning of all Japanese television shows, cautioning viewers not to sit too close to the television screen and to watch only in a brightly-lit room: 「テレビアニメを見るときには、部屋をあかるくして近づきすぎないようにしてみてくださいね。」

A study following 103 patients over three years after the event found that only 22% were reported to have had seizures after the incident. 15 of these patients were determined to have had visually induced seizures, while 56% of the patients who did have more seizures following the incident also had epilepsy. The three-year study of 103 surveyed patients also found that only 25 (24%) of them were determined to have had seizures before the incident took place.

Photosensitive Seizure Disorders

Photosensitive Seizure Disorders are characterized by their common trigger: flashing, intermittent light, and visual patterns. While epilepsy is the most known seizure disorder, it is not all there is.

Other types of Seizures

We currently distinguish between Focal and Generalized Seizures. Focal Seizures start in one area of the brain and may or may not affect awareness, hence, they are called Focal Aware (Simple Partial) Seizures or Focal Impaired Awareness (Complex Partial) Seizures.

Generalized Seizures involve both hemispheres from the get-go and usually lead to loss of awareness for the duration of the seizure. The best-known one, the poster child of Epilepsy, is the Tonic-Clonic or Grand Mal Seizure. It is characterized by Dragon Ball Fusion of 2 types of seizures:

• Tonic: Muscles suddenly become stiff, usually affecting the arms and legs, which can cause falls and injury.
• Clonic: Rhythmic jerking movements (Clonic seizures alone occur without the stiffening phase of tonic-clonic seizures)

Now that we know Tonic and Clonic, the next ones won’t surprise you much:

• Myoclonic: Characterized by sudden, brief jerks or twitches of muscles, but usually no loss of consciousness.
• Atonic Seizures (Drop Attacks): Sudden loss of muscle tone, causing a person to collapse or fall. Often leads to head injuries due to lack of warning.

Makes sense, right? Myoclonic is a smaller scale version of clinic seizures, and Atonic is the opposite of tonic, with loss of muscle tone instead of stiffness. There’s one more type of generalized seizure which looks different to all of the above:

Absence Seizures or Petit Mal Seizures. They are characterized by brief episodes of blanking out (5–15 seconds). They don’t come with convulsions, but with confusion, as the person loses awareness of their surroundings during this type of seizure.

SUDEP

Something else I learned from my LinkedIn comments: SUDEP or Sudden Death in Epilepsy.

SUDEP stands for Sudden Unexpected Death in Epilepsy and is a serious risk for all people with epilepsy. Each year, approximately one in 1,000 affected individuals dies from it. However, even simple measures can help significantly reduce the risk.

The Epilepsy Foundation offers resources on Seizure First Aid.

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This post was originally published on a11y News Newsletter.