“On the evening of 16 December 1997 approximately 700 people around the nation (mostly children) were rushed to hospitals and treated for seizure symptoms. The youngsters had been watching the vastly popular TV animated cartoon series Pocket Monsters (Pokemon).” Pocket Monster incident and low luminance visual stimuli: special reference to deep red flicker stimulation. Acta Paediatr Jpn. 1998 Dec;40(6):631-7.

We all heard about the Pokemon Seizure incident, but what is the scientific evidence behind it? I searched for “pokemon seizure” on PubMed, a searchable online database of articles from medical journals maintained by The National Library of Medicine, and came up with few interesting articles. I’ll summarize a few of their findings in chronological order.

[1998] Initial reports accused the low luminance, 12 Hz alternating red/blue stimulus as the cause of the Pokemon incident. Early studies considered the possibility that some healthy youngsters may have latent photosensitivity and such a sensitivity might be disclosed by use of low luminance deep red flicker stimulation. Pocket Monster incident and low luminance visual stimuli: special reference to deep red flicker stimulation. Acta Paediatr Jpn. 1998 Dec;40(6):631-7.

[2001] Further studies were done on the role of long-wavelength red light emission from TV in the induction of photosensitive seizures by an animated TV program called “Pokemon”. Conclusion: High amounts of long-wavelength red light emitted from CRTs might play an important role in induction of photosensitive seizures in “Pokemon” incident. However, the small sample number (n=11) makes this conclusion slightly weak, but does bring up the “possibility” of the association with red light emission induced seizure. Long-wavelength red light emission from TV and photosensitive siezures. Acta Neurol Scand. 2001 Feb;103(2):114-9

[2001] However, despite the mounting scientific evidence, others claim that the photo-induced seizure alone cannot account for the breadth and pattern of the events. “The characteristic features of the episode are consistent with the diagnosis of epidemic hysteria, triggered by sudden anxiety after dramatic mass media reports describing a relatively small number of genuine photosensitive-epilepsy seizures.” Pokémon contagion: photosensitive epilepsy or mass psychogenic illness? South Med J. 2001 Feb;94(2):197-204.

[2002] Many studies characterized the hospitzlied children to determine the risk factors to photo-induced seizure. Higher incidence of induced-seizure were found in children who (1) concentrated in watching the show, (2) watching it in short distance, (3) watched in a lowly lit room, and (4) had familial history of seizure. A comparison survey of seizures and other symptoms of Pokemon phenomenon. Pediatr Neurol. 2002 Nov;27(5):350-5.

[2008] General risk factors and association with photo-induced seizure. The overall prevalence of the photoparoxysmal response (PPR) among patients requiring an EEG is approximately 0.8%, but 1.7% in children and 8.87% in patients with epilepsy, more often in Caucasians and females. Autosomal dominant inheritance is indicated, and this response is seen especially at the wavelength of 700 nm or at the flicker frequency of 15-18 Hz. The PPR extending beyond the stimulus carries no increased risk of seizures. Prognosis is generally good, especially after 20 years of age. Attention to PPR has been increased with the advent of video games, and the evoked seizures from these games are likely a manifestation of photosensitive epilepsy. Drug therapy has emphasized valproic acid, but Levetiracetam has also been successful in eliminating the PPR. The photoparoxysmal response: the probable cause of attacks during video games. Clin EEG Neurosci. 2008 Jan;39(1):1-7.

You know who the real victim of all this is? Your friend who has to drag you to the hospital after finding out that you watched Pokemon that evening.

Pikachu doesn’t seem so cute now does he?