Flicker Vertigo

DanAyers

Member
Joined
Mar 6, 2003
Location
United States
So, For anyone who doesn’t know, I hold a Master’s degree in Occupational Safety Management; which goes well with my Bachelors in Technical Theater and 20 years working in the industry.

One of my professors from the safety program reached out to me this morning, after attending Trans Siberian Orchestra in Kansas City last night she experienced flicker vertigo from the lights moving and flickering too fast during the performance. I’m not terribly familiar with flicker vertigo, and I learned a few things about it from her today but I’m curious if people here are more knowledgeable than me and if it could spark a good discussion about what it is, and what LD’s need to look out for to prevent it. Personally, I’d like to understand it better, so I would love to hear stories, and any information anyone wants to share.

I guess to start here’s a definition:

Flicker vertigo, sometimes called the Bucha effect, is "an imbalance in brain-cell activity caused by exposure to low-frequency flickering (or flashing) of a relatively bright light."[1] It is a disorientation-, vertigo-, and nausea-inducing effect of a strobe light flashing at 1 Hz to 20 Hz, approximately the frequency of human brainwaves.[2][3] The effects are similar to seizures caused by epilepsy (in particular photosensitive epilepsy), but are not restricted to people with histories of epilepsy.
This phenomenon has been observed during helicopter flight; a Dr. Bucha identified the phenomenon in the 1950s when called upon to investigate a series of similar and unexplained helicopter crashes. Flicker vertigo in a helicopter occurs when the pilot or front passenger looks up through the blades of the main rotor as it turns in the sun causing the light to strobe.

So what stories do you have?
Thanks
Dan
 

TuckerD

Active Member
Joined
Mar 1, 2012
Location
Rochester, NY
Very interesting! This weekend I'll see if I can find any literature on it. Cool background (OSM) by the way. Probably not enough of that in the industry.
 
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macsound

Well-Known Member
Joined
Jun 15, 2018
Location
San Francisco, CA
Seems like it would be an interesting phenomenon to look at because concert lighting is soooo flash and trash lately and stobe effects have become more convoluted with the advent of LED engines and designers creativity such as strobing through color, gobos and movements.
 

MNicolai

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Fight Leukemia
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Mar 30, 2008
Location
Sarasota, FL
Probably similar triggers but unique causes. Epilepsy affects select individuals. Flicker vertigo messes with your visual perception of space, speed, and proximity; and can induce symptoms in any individual under the right circumstances.

It's like those really slow strobe effects in haunted houses. The deliberately long cycle between flashes messes with your ability to accurately perceive which direction something is headed, how quickly it is moving, and which was it up.
 

Malabaristo

Well-Known Member
Joined
Jul 11, 2008
Location
Wisconsin
Flicker vertigo messes with your visual perception of space, speed, and proximity; and can induce symptoms in any individual under the right circumstances.
It would be interesting to see research on how true this is. What portion of the population is more or less susceptible to which kinds of flicker? If there are certain values that affect almost anyone, then it would be useful to have those as parameters when designing silly flashy things. My guess is that those levels would have to pretty extreme for an average person, but there's a smaller subset of people who are much more sensitive to some (all?) kinds of flicker. If everyone at the TSO concert had the same reaction as Dan's professor, then you'd think those shows would be less popular.
 

DanAyers

Member
Joined
Mar 6, 2003
Location
United States
It would be interesting to see research on how true this is. What portion of the population is more or less susceptible to which kinds of flicker? If there are certain values that affect almost anyone, then it would be useful to have those as parameters when designing silly flashy things. My guess is that those levels would have to pretty extreme for an average person, but there's a smaller subset of people who are much more sensitive to some (all?) kinds of flicker. If everyone at the TSO concert had the same reaction as Dan's professor, then you'd think those shows would be less popular.
I want to clarify one word, I want to replace “True” with “widespread”.

I don’t think it is very widespread but for her it is “true” Interestingly enough she recognized it and she made a video of that part of the show with her phone specifically so she could ask me about it later. And it is flashy.

What would make for an interesting study would be to gather data and identify correlations.
What percentage of audience member exhibit mild symptoms that do not warrant medical care? How long? Is it the same part of the show; etc.
 
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TimMc

Well-Known Member
Joined
Feb 15, 2017
Interesting topic, and one that my shop encountered last year.

We had a small arena show with a popular 1980's act who carries no LD but has a general plot and color media list in their rider. Our LD contacted the act and got a set list, downloaded the songs from youtube and built a show. LD also watched recent live performance vids to have an idea of what the band was accustomed to.

At sound check we are told by the tour manager that the light show needs to be re-done because a member of the rhythm section has vertigo-like episodes from flashing & panning lights. Really? We've been in direct contact with you, Mr TM, and you never mentioned this. We've been in contact with the production manager and he's not brought it up when asked if there were looks the band did NOT want used. The soap opera that followed did not include me directly, but the client specifies the "general" nature of the shows we do for them unless the act has a specific plot & LD (think: Styx - Love ya, Libby!) and we were reluctant to scrap the entire design. Ultimately our LD went in and edited each look to give the affected player a "hidey-hole" of space where no movers scanned across or up/down, turned the strobe cues into longer burns and did a couple other things. The result was acceptable to our client and the musician was not incapacitated on stage. Also no animals were harmed... 😺🐶🐰🐼

But it's a real issue and some folks seem to be particularly susceptible to it and it could make a player's "day at the office" really suck. Ultimately we don't want anyone's day to suck so we'll find a way to de-suckify the offending issue.
 

CM Wardrobe

Member
Joined
Jan 8, 2020
Location
Minneapolis., MN
I know of a couple coworkers who experienced flicker vertigo symptoms when the theater that I work at did an upgrade to LED lights in the entire building. I'm not sure for stage lighting, but I know that there are areas of the building where the new LED lights do really flicker. I think that things that have been helpful are having the right fixture and the quality of the bulb.
 

Pyrotech

Member
Joined
Mar 15, 2017
Location
Shelton, WA
Working in the utility industry energy efficiency program, I would sometimes run into people who would complain of headaches caused by fluorescent lights. Most thought it was from the poor color quality and 'harshness' of the fluorescents, but most said the headaches were lessened when we upgraded them to the newer T8 lamp/electronic ballast combination (I was in the industry long enough ago for that to be the 'latest and greatest - pre-LED), which operate at 20,000 Hz rather than 60 Hz (or 50 Hz, for you non-continental US folks)
 

Jenn4art

Member
Joined
Jan 9, 2020
Location
Minnesota
So, For anyone who doesn’t know, I hold a Master’s degree in Occupational Safety Management; which goes well with my Bachelors in Technical Theater and 20 years working in the industry.

One of my professors from the safety program reached out to me this morning, after attending Trans Siberian Orchestra in Kansas City last night she experienced flicker vertigo from the lights moving and flickering too fast during the performance. I’m not terribly familiar with flicker vertigo, and I learned a few things about it from her today but I’m curious if people here are more knowledgeable than me and if it could spark a good discussion about what it is, and what LD’s need to look out for to prevent it. Personally, I’d like to understand it better, so I would love to hear stories, and any information anyone wants to share.

I guess to start here’s a definition:

Flicker vertigo, sometimes called the Bucha effect, is "an imbalance in brain-cell activity caused by exposure to low-frequency flickering (or flashing) of a relatively bright light."[1] It is a disorientation-, vertigo-, and nausea-inducing effect of a strobe light flashing at 1 Hz to 20 Hz, approximately the frequency of human brainwaves.[2][3] The effects are similar to seizures caused by epilepsy (in particular photosensitive epilepsy), but are not restricted to people with histories of epilepsy.
This phenomenon has been observed during helicopter flight; a Dr. Bucha identified the phenomenon in the 1950s when called upon to investigate a series of similar and unexplained helicopter crashes. Flicker vertigo in a helicopter occurs when the pilot or front passenger looks up through the blades of the main rotor as it turns in the sun causing the light to strobe.

So what stories do you have?
Thanks
Dan
Hi Dan,
I can't speak to the vertigo in visible flicker like you mentioned in this instance but in the last year I have discovered I have sensitivity to subsensory flicker between 100-400hz from LEDs. This is area lighting primarily in buildings and streetlights. But I work in live theater on wardrobe and now that LEDs are more prevalent in design I've had to stop going to see live productions from the audience perspective. LEDs not properly installed with drivers to compensate for AC power will flicker (in US) around 120hz. But since live productions typically use dimmers, and since LEDs don't dim, the dimmers are increasing the flicker in this range that I'm sensitive to. I have experienced migraine headaches, dizziness, stroboscopic effects, nausea and concussion like symptoms from these lights and the only way I can get rid of the headache is an experimental treatment dependent on office hours.