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Why Powerpoints Put You To Sleep

dlp photosensitivity flicker seizure topomax

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#1 cnlmustard



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Posted 24 February 2013 - 01:18 AM

I have read some previous posts to this forum on the topic of triggers of narcoleptic symptoms, like cataplexy, with one of particular interest to me - lighting flicker.


At most conferences and seminars, there is usually a person speaking, and a batch of slides shown on a screen with a “Powerpoint” projector.


Now without trying to put everyone to sleep here (LOL), there is one type of projector which I believe is evil in it’s nature, to us with narcolepsy. In fact, at the next NN conference, a study should be made of this. Why should we be torturing our own attendees?


The projector type of choice for the last 5 or so years has been the DLP. This basically has a little color wheel spinning in front of the lamp, flashing an alternating stream of red-blue-green-white components of each frame of the picture or video in sequence, about 70 to 80 times a second. This is sent to your brain, you don’t process the harsh flicker, but the brain still sees it. It’s similar to the flashing lights used during an EEG test at the hospital for epilepsy.


You know this has GOT to mess with us with N. The blue-red blink makes some normal people feel seasick, it’s called photosensitivity syndrome. Unfortunately I’ve got that along with my narcolepsy now. I’m an instructor and need to get my DLP’s changed over to LCD projectors. They don’t flicker, they just replace color frames in sequence.


Old movies flickered, with black spaces between, but the flicker was much slower so it didn’t make anyone sick. CRT projectors in old sports bars worked like television tubes and old type fluorescents, there’s a glow between flickers, so it’s not harsh. New flourescants have very little flicker.  Incandescents are great, they just steady glow, but unfortunately they’re energy hogs.


Now LED’s that get their power from AC current, they convert it to 120 harsh flicks per second DC, so those  are really hard to deal with for me.

#2 exanimo



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Posted 01 March 2013 - 09:03 AM

Very interesting! I am not familiar with how light changes affect the brain and sleep center. Besides the recent research in to light and how it's not good to watch tv, or be on your computer or on your phone within so long before going to sleep. But if anyone has any articles that cover this, that would be interesting to read. 


I know that for me, anytime I'm in class, it's hard to stay awake. But it's so much worse if we watch a movie. I swear, within about 10 minutes of the tv (or projector) playing a movie, I am out. And I'll wake up a few times, but I generally fall right back to sleep. It sucks, especially in classes where they show a lot of movies or documentaries. Thank goodness, I'm not going into film! 


Powerpoints though, don't generally put me to sleep unless the professor is very monotone. I fall asleep a lot when my classmates have to give presentations and use the powerpoint, because they aren't usually the best presenters. I also take a lot of notes because I've found it's the best way to help me stay 'mentally alert' and awake during classes. Although, when I do fall asleep, and I look back at my notes later, it's quite pathetic and never useful. But that's not the point of them - it's just a way for me to stay awake. :D 


I would love to ready some more information on this, so if anyone else has any links that would be awesome!