Why Do Flashing Lights Cause Seizures?

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Published by:
Practical Psychology
Andrew English
Reviewed by:
Andrew English, Ph.D.

Have you ever seen a warning cautioning photosensitive viewers about strobe lights? These warnings may appear before a TV show or be posted outside a rock concert. What you may not know is that those warnings are created to prevent people from having a seizure.

Don't worry. If you have never experienced a seizure before, know that this is a rare condition. It's even rare among people with epilepsy! But you may be curious why these warnings exist. Let's discuss photosensitive epilepsy and why flashing lights may cause seizures.

Why Do Flashing Lights Cause Seizures?

Flashing lights cause seizures because the neurons that respond to these stimuli overreact. Certain light patterns may also put people at risk of feeling sick or dizzy for the same reason. Their neurons send out an unfavorable response to that stimuli.

You may be surprised to learn that one in ten people will experience a seizure at some point in their lifetime. However, experiencing a seizure does not necessarily mean that an individual has epilepsy. To put this in perspective, approximately 1.2% of the U.S. population has been diagnosed with epilepsy, with 0.6% being children. This statistic helps clarify that while seizures can be common, chronic conditions like epilepsy are less so.

Epilepsy is a neurological disorder characterized by recurrent, unprovoked seizures. Seizures, in the broad sense, can have many triggers, including illness, brain injury, and in some cases, flashing lights. This sensitivity to visual patterns, especially flashing lights, is known as photosensitive epilepsy (PSE).

What is a Seizure?

A seizure occurs when the neurons of the brain fire off uncontrolled signals to the rest of the body.

A neuron's job is to fire off signals, but usually, these signals help us form "normal" responses. For example, we may squint at the sight of the sun or recall a memory at the sight of something we hadn't seen in a while. When too many neurons fire at once, they cause the body to respond in unintentional and sometimes harmful ways.

Not all seizures look the same. Grand mal seizures may look like the "typical" seizures you see on television. The person having the seizure loses consciousness, and various body parts twitch and jerk. But there are other types of seizures in which the person appears to "zone out."

It may come as a surprise to discover that one out of every ten individuals will experience a seizure at some point. However, it's important to note that this does not imply that one in ten people have epilepsy.

Seizures may happen for a variety of reasons:

  • High or low blood sugar
  • Use of controlled substances
  • Fever
  • Missing medications
  • Injury
  • Lack of sleep
  • Infections
  • Stroke
  • High salinity in the blood
  • Tumors

Seizures may also happen "randomly." There is still a lot that scientists don't know about seizures, and it is hard to study seizures when they do happen randomly.

When a person experiences multiple seizures, they may be diagnosed with epilepsy. People who have seizures due to flashing lights have "photosensitive epilepsy."

Your Brain and Flashing Lights

Our neurons are firing constantly as the brain processes the visual stimuli in front of us. Our eyes, particularly the rods and cones receptors in the retina, convert light and shadows into neural signals. Rods are more numerous and are responsible for vision at low light levels, while cones are less abundant but are crucial for detecting color and fine detail. These two types of photoreceptor cells work together to interpret the visual world in varying lighting conditions.

Once the light is detected and converted by these photoreceptors, the signals travel through the optic nerve to the thalamus and finally to the visual cortex at the back of the brain. This complex journey delivers critical information about the environment we are navigating.

For individuals with photosensitive epilepsy, the rapid and constant changes in light intensity can be overwhelming. The usual process of light conversion and signal transmission, which involves rods and cones adapting to the fluctuations, becomes an intensive task. In those susceptible, this intense neural activity is enough to trigger a seizure.

Interestingly, while flashing lights can pose a risk for seizures in some, they may also serve as a therapeutic tool for others. Research into Alzheimer's disease has explored the possibility that using light to stimulate brain activity could prevent the buildup of harmful plaques that cause cognitive decline. This suggests that under controlled conditions, targeted light stimulation may potentially fortify certain neural pathways and help maintain cognitive function.

How Many People Have Seizures Because of Flashing Lights?

Photosensitive epilepsy affects 3% of all people who experience epilepsy. That's approximately one in 10,000 people. Children are more likely to experience photosensitive epilepsy (and epilepsy in general).

While it is possible for an adult to experience epilepsy, many children who have seizures grow out of the disorder by the time their brains are fully developed.

How Long Does a Seizure Last?

Seizures may last as little as 30 seconds but generally last up to two minutes. A seizure that lasts for more than five minutes is considered a medical emergency and requires immediate attention.

Can Photosensitive Epilepsy Be Treated?

Some people do grow out of a seizure disorder over time, but no one cure can be universally applied to all people experiencing seizures. Fortunately, some medications can prevent all types of seizures.

People with photosensitive epilepsy can prevent seizures by avoiding flashing lights. This is why concert venues or video game manufacturers issue these warnings - to help people who may need to know if there are potential risks!

Case Study: The Pokémon Episode Incident

An illustrative example of flashing lights inducing seizures is the 1997 Pokémon episode incident in Japan. The episode in question, “Dennou Senshi Porigon,” featured a scene with rapidly flashing lights that resulted in 618 children being taken to hospitals with symptoms ranging from nausea and headaches to seizures. This mass event led to the widespread acknowledgment of the potential dangers associated with flashing images, particularly in individuals with photosensitive epilepsy (PSE).

However, this case also opened discussions on the psychological aspects of seizure-like events. Research indicated that many reported symptoms were atypical for PSE, which classically includes drooling, stiffness, and loss of consciousness. The phenomenon's scale was also inconsistent with the estimated prevalence of PSE, which affects approximately 0.02% of the population.

Subsequent analysis suggested a potential influence of mass hysteria. Most affected viewers exhibited symptoms after the initial broadcast, influenced by media coverage and peer discussions rather than the episode itself. This points to the complex interplay between neurological triggers and social factors in seizure incidents. Understanding such events requires a multidisciplinary approach, considering medical science and psychological dynamics.

The Pokémon panic is a cautionary tale on the effects of flashing lights on the brain and underscores the importance of content warnings. It also demonstrates the need for careful epidemiological and psychological assessment following such events to discern between direct neurological reactions and socially induced responses.

What To Do If Someone Is Having a Seizure Around You

There is no way that you can tell a person's neurons to stop firing or fire at a less intense rate. What you can do is make sure they are safe and calm during and after their seizure occurs.

If a person is experiencing a seizure at a concert or while watching television, gently help them to the floor. Clear the area of sharp objects and put something soft under their head. It may also help to put the person on their side. Remove their glasses and anything that may put them at risk (e.g., a tight tie, a spiky bracelet, etc.)

It is an old wives' tale that says a person may swallow their tongue during a seizure. Do not try to hold a person's tongue or put anything in their mouth during the seizure. They don't need mouth-to-mouth, either!

Once you know the person is safe, check for a medical bracelet. These bracelets may offer more information on whether this person has a seizure disorder.

Unless the person is experiencing a seizure for over five minutes or they have never had a seizure before, you will not need to call 911. Wait by the person until they regain consciousness, and calmly ask them if they need any food or drink. If you are at a concert or playing a video game that may have caused the seizure, help the person remove themselves and enter a calmer environment.

Flashing lights may be one cause of seizures, but knowing what to do and why this occurs is crucial to keeping people safe. Be sure, if you are hosting an event with strobe lights, to let people know they are at risk!

Reference this article:

Practical Psychology. (2022, April). Why Do Flashing Lights Cause Seizures?. Retrieved from https://practicalpie.com/why-do-flashing-lights-cause-seizures/.

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