Flashing lights trigger seizures, so don’t use them

Quick PSA post: Flashing lights trigger seizures. This means the strobes people put on bikes, the flashing hazard lights used for almost anything, well, hazardous, the flashing lights on emergency vehicles (which is pretty counterproductive), and the flashing lights that go along with some smoke alarms (also counterproductive). People having seizures matters. Seizures suck. The period after a seizure (the post-ictal period) is described to me as “a really bad hangover.” K has a great stream-of-consciousness post-ictal blog post so you can get an idea of what it’s like. Besides the obvious danger during the actual seizure (hitting your head if it’s a tonic-clonic, crashing if you’re operating a car or bike, falling, etc.) there’s the danger that comes from not knowing what’s going on, where you are, and where your home is, and how to get there for hours after your seizure. K once sat down on the light rail tracks and refused to move after a seizure. Luckily she had a friend there that’s really good at speaking K-ish when she’s had a seizure, and she eventually moved. But people with epilepsy don’t have friends around all the time that can look after them (because they shouldn’t need keepers to have a life). Having a seizure in public is a very dangerous thing, and flashing lights are pretty successful in making that happen.

So what can you do? At the very least, set your bike light to a steady beam. The brain tracks that better than a strobe anyway. If someone asks you to stop doing something because it might cause them to have a seizure, listen to them. If you want, write Letters to police and fire departments asking them why they use seizure-triggering lights while they are trying to alert people to danger. (There are other options available, even if it’s just a different frequency of flashing.) And tell other people. The world should be safe for everyone, not just neurotypical people.

Posted on January 7, 2012, in epilepsy. Bookmark the permalink. 15 Comments.

  1. Strobing lights on a bike are much more likely to get the attention of a motorist than a steady light. Especially in an area where there are lights and lit signs all over the place. I would be more worried about being hit by a car that didn’t see me than causing someone to have a seizure (and I really think it unlikely that my red blinker on the back of my bike would cause anyone to have a seizure).

    But for the most part, I agree about any unnecessary strobes. Bright strobing lights have never caused me a seizure, but they do hurt my eyes and cause me to get headaches. Generally annoying…

  2. Heya, Mikel!

    What you just said is “my bike light that I BELIEVE grabs attention is more valuable than the lives of those with epilepsy”.

    Cuz, see, a strobe light makes things that are still looking moving and things that are moving look still and you cannot tell if they are moving towards you or away for quite some time. A solid light has much more clear “I am moving this way”.

    And of course, there’s the slight problem (read as: large problem) that someone with partial complex seizures from strobe lights can be put into a state of “walking into the street” because their brain shuts down. Or someone with generalized tonic clonic seizures can be put into a state of “falling and flailing with a bonus of a TBI from hitting the concrete”! Or, my favorite, trying to protect oneself from a neurological terrorist leads to being run into & sworn at by said neurological terrorist (that’s cyclists. We’ve had Words. I’ve been threatened. It’s awesome) because really the only thing I can do, especially when they’re on my side*walk*, is cover my eyes.

    Don’t be an ableist jerk (anymore. “I’d rather cause someone a seizure is kind of ableist and shitty, if you were wondering). Just use the solid beam. It’s not hurting you, whereas the strobe absolutely could be.

  3. Wow, really. “ableist jerk”? I might consider your advice next time I go out on my bike at night, as I know that people unaffected by a particular issue might be blind to it’s affects. But name calling does not encourage me to continue this conversation all the same.

    • speakingupanyway

      Strobe lights on bikes aren’t necessary. They attract attention, but they’re much worse when it comes to our brains’ ability to track movement and determine where the source of the light is. (There are studies to support this, but since the fact was established way back in the ’60s, they’re not online to link to. Annoying.) You know how everything looks weird and slow-motiony in a room with a strobe light going? Same thing happens with strobes on bikes. Steady beams are trackable, and they have the added bonus of not having a 65% chance in triggering a seizure in someone with photosensitive epilepsy. (That’s assuming the strobe is only 10hz; the higher the frequency, the higher the incidence of seizures.) It really comes down to a choice of what’s more important to you: having a light that you like, or making sure that you don’t gravely endanger the lives of your fellow humans. Your call.

      • Thanks for the information. This is the first time I’ve heard any of this. Thanks also for not calling me a jerk for questioning the idea that flashing bike lights could be a danger to anyone. A flashing red light is recommended to bikers riding at night on all sources on safety that I have seen, and there is very little information out there where bikers actually look that would indicate that flashing lights could cause problems. I’ll consider that next time I ride at night, but do you know of any advocates who are trying to get this information out to bike safety organizations?

      • speakingupanyway

        Kassiane’s a major activist in that area. The reason she comes across as mean is that for years, when she’s been nice, no one has listened to her, and when she’s stood her ground, she’s gotten rape and death threats. She’s also been beaten and stabbed for her autism activism. It sounds like you really do want to learn, and you do care, and that’s awesome. I wish it was the most common response people gave when this issue is brought up.

  4. Bike safety organizations are uninterested. If you’re nice, they ignore you. If you’re not nice (because having the same conversation 100 times a day gets tiresome, especially if you’re also fighting off a seizure), they threaten you with rape and/or murder and THEN ignore you.

  5. On thing to remember about bicyclists is that we (especially bike commuters who are need to be our in pre-dawn and post dark hours) have to have our lights, and flashing lights are better for getting attention than steady lights. The human brain notices a changing thing more than a steady thing, and if you have a vehicle coming up behind you at 3 or 4 times your speed, you need to get their attention as fast as possible. I know blinking lights work very well because I have been the motorist driving behind the cyclist at night on several occasions. So when you say that cyclists should not use their rear blinkers, it sounds like you are asking us to compromise our own safety due to the rare chance that a driver behind us might be epileptic and might be sensitive to our blinker.

    Surely there is some middle ground here. This whole topic has me concerned.

    • speakingupanyway

      Try a light with a very low frequency of flashes. 10hz, or ten flashes per second, will trigger seizures in 65% of the susceptible population. If you go down to 4hz, or 4 flashes per second, only 5% of the susceptible population is at risk. Blinking lights do get attention, but blinking isn’t as much of a problem as the strobe, and the lower frequencies will be easier for motorists to track momentum on, since the light is steady longer. Like you said, dawn and dusk are high-risk times for bikers, but if you’re outside of those times, a steady beam may be safe enough.

      Also, I understand that there is some element of balancing the safety needs of both sides, but don’t discount the safety and access needs of epileptics because you think it’s unlikely that you’ll cross paths with one. It’s a common thought among the abled, and it results in the needs of the disabled being relegated to second class. Yes, your incidence of corssing paths with someone with photosensitive epilepsy may be small, but every time they walk out the door, they go into a world that has a constant barrage of seizure triggers. Count how many times you see a flashing light in one day. Now imagine that every time you see one, you’re in danger of having a seizure right where you are at that moment. It’s a lot, and the only way to make the world more accessible is to get a large number of people to make a little change, like using a low-frequency light, or, better yet, a steady beam. Yes, your safety needs are important. But people with disabilities should be able to access the world as freely as you can.

    • One thing to remember is we (epileptics) also have to get places. We cannot arrange our schedules and routes around where cyclists may choose to be. Many of us are dependent on transit and walking because many states have a 1 year seizure free wait period to get a license. Those of us who are photically triggered have never seen a seizure free period in our lives between cyclists, flash photography, & dying flourescent lights.

      Flashy lights actually don’t grab attention in the way you think. A non epileptic person will have EEG changes called photic driving response, which makes the brain waves synch up with the flashes (this is also how photosensitive seizures start, btw). This causes a bit of an altered state, to the point that people who think trances are a good idea chill out with a strobe light to induce that spaced out feeling.

      I don’t particularly want people who aren’t epileptic spaced out either.

      I also really don’t understand how a non flashy light is more likely to get hit than a flashy one? It’s not like people just drive themselves smack into lights. At least no one I know.

  6. Hummm…interesting. I’ll take a look at my lights and see what the flash frequency is. And there is one particularly bright strobe that I use that I could probably use without the flash.

  7. speakingupanyway

    You’re AWESOME!

  8. Thanks…thank my feminist activist friends for introducing me to the concept of privilege. If I didn’t know about that, I probably would have turned off my brain immediately when I read the post.

    • speakingupanyway

      I don’t get why people do that. They get so defensive when you point out that they have privilege, and this might be a situation where other are marginalized without their knowledge, and perhaps they could behave differently. It seems to me that the response of, “Oh, I didn’t know that. Can you tell me more? I won’t do that anymore.” makes so much more sense. Sigh.

  9. This is such an interesting discussion. I’m glad that my Google Alert for seizures and flashing lights brought it to my attention. I think visually induced seizures are more common than people realize, because they affect plenty of people who don’t have seizures at other times, and because seizures can be very subtle and are never identified.

    I have a blog on seizures from video games (http://videogameseizures.wordpress.com), so a lot of this feels very familiar. I can tell you the video game industry isn’t too interested, either in hearing about making their games safer for those with photosensitive epilepsy. Gamers in general are hostile to the subject because they feel that altering game visuals to make them less visually provocative detracts from the thrill of the game.

    Epilepsy advocacy organizations aren’t interested in pursuing it aggressively, either. In my experience the epilepsy organizations don’t have photosensitivity on their agenda—they want cures and health care accessibility and an end to job discrimination. These are all important. But the everyday life of those with visual sensitivity, as has been pointed out here, is full of hazards from very common things in the environment. We know already what needs to be done to make life safer for this population, but getting things changed in existing products is an uphill battle.

    The epilepsy organizations as well as everyone else assume that photosensitive seizures are a problem just for a small percentage of people with epilepsy, when in fact 75 percent of folks who have their first photosensitive seizure have never had a seizure before. And they may never develop “regular” epilepsy, where seizures occur without a visual trigger. So it’s a larger public health and safety problem that should concern everyone. Most people with this genetic condition have no idea they are vulnerable to flashing light until a particular stimulus under the right conditions sets off a seizure.

    The other problem with trying to make the world safer for people with this type of reflex epilepsy is that many folks with “regular” epilepsy (who are not also photosensitive) already feel marginalized and don’t want any more attention drawn to their differentness. They are trying to live typical lives as much as possible, and they feel if there’s too much talk about seizures being triggered by everyday situations, everyone around them will always be unnecessarily concerned about their seizure vulnerability. In addition, parents of kids with seizures try to encourage their kids to live normal lives and don’t want them to think they’re different or disabled.

    And another thing: the neurologists who are knowledgeable about photosensitivity (most aren’t) tend to rely on studies suggesting that small sources of flashing light, such as a bike light, don’t take up a large enough part of the overall field of vision to affect the brain significantly.

    So, I’m glad to see this being talked about.

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