More information on PSE

Historic research indicates that as a condition PSE affects approximately one in four thousand people. As well as these diagnosed cases, there are many more people where the condition lies dormant just waiting for the right trigger. The most susceptible age for PSE to be diagnosed is in the age group 7 to 20 where first-seizures are five times more prevalent than at other ages. Once diagnosed, three quarters of patients remain photosensitive for life.

A major difficulty with these statisitcs is the fact that for PSE to be diagnosed, seizures have to be identified, reported and investigated.

While the actual prevalence of seizures triggered by video and similar visual stimuli remains difficult to ascertain, a growing body of research challenges the commonly held premise that they are extremely rare events (Kasteleijn-Nolst Trenité, 2004; Hennessy, 2000). When nearly 700 children watching a Pokémon cartoon broadcast in 1997 went to hospitals across Japan because they experienced seizures from a brief visually provocative sequence, it was found that 76 percent of the children had no prior seizure history. The number of children affected, the absence of prior seizures in so many of them, and other emerging findings led researchers to consider that vulnerability to visually induced seizures maybe a more pervasive problem than previously realized.

Studies have also shown that video stimuli can trigger complex partial seizures that are subtle and therefore can often occur undetected. Unfortunately, when there is little awareness that these seizures can happen, the people who are vulnerable don’t realize they may be at risk, don’t limit their exposure, and as a consequence may experience repeated disabling seizures that most likely could have been prevented. Neurologists without expertise in reflex seizures who are not familiar with the most recent research may apply strict diagnostic criteria that rule out correct identification of the condition.

As an example of this, Jessica, a mother, learned about visually induced seizures by reading research papers while searching for a neurologist who could help her daughter Alice. For a long time neither Jessica nor the doctors she consulted had considered seizures as a possible cause for Alice's chronic medical, mood, and neuropsychiatric difficulties. Once Jessica suspected that Alice was having reflex seizures (triggered in this case by video games), she faced an unexpected challenge to find a doctor who agreed. Understanding Alice’s case required doctors to set aside skepticism based on the prevailing view that video game seizures were unmistakably obvious events.

Who should care about this, anyway?

People with epilepsy for a start. The prevalence of photosensitivity may well be underestimated for people with generalised epilepsy. The way IPS is administered can affect the results. A negative finding on routine photic stimulation does not rule out sensitivity to the complex stimuli often contained in video. The seizures experienced due to visual stimuli could be different than the typical seizures of an individual with epilepsy, and therefore might not be easily identified as seizures by that person or EEG. It could be that the visually induced seizures occur in a part of the brain that is too far from scalp electrodes to be detected on EEG. It may be that an effective anticonvulsant fails to protect against both spontaneous and provoked seizures.

And people without epilepsy. Most individuals experiencing a visually sensitive seizures had not consider themselves at risk, because they had never seriously considered the possibility or had a seizure prior to their first visually triggered episode. Some researchers suggest that it is likely that susceptibility to seizures from visual stimuli is dormant in a considerably larger portion of the population than previously thought, and that today’s media-saturated environment overwhelms the seizure threshold for increasing numbers of these people—whether or not they’re aware of it (Kasteleijn-Nolst Trenité, 1999). Based on the Pokémon incident, Takahashi et al. suggest that “nonepileptic photosensitivity” (where seizures occur exclusively in response to visual stimuli) occurs at twenty times the rate of epileptic photosensitivity (Takahashi, 2004)!

Video game manufacturers Game manufacturers publicly acknowledge their games can induce seizures. They place warnings on their products to alert users of the risk, although those who play online may not see these notices. However, since nearly every consumer product we purchase is accompanied by disclaimers and safety warnings, nobody pays attention. The seizure warnings are inadequate, since few people take such warnings seriously, and fewer still know enough about partial seizures to identify the signs and symptoms should they occur. Given the common misperception that all seizures are tonic-clonic, most people reading a warning dismiss it as irrelevant because they haven’t ever had one.