Study challenges reliability of EEG test for photosensitivity

ouijaboard

The EEG strobe test produced astonishingly unreliable results in a recent study.

If the results of a recent study at SUNY at Buffalo are any indication, there are an awful lot of people vulnerable to visually induced seizures who are being told they aren’t at risk. The study showed that testing for photosensitivity using EEG with photic stimulation provides unreliable information. In the wake of these findings, ruling out photosensitive epilepsy–and ignoring the seizure risk from video games–simply on the basis of intermittent photic stimulation results would seem very unwise.

This study–not yet published–by the Buffalo research team found that the test is poorly correlated with vulnerability to visually induced seizures in everyday life. Just 6.2 percent of patients with a history of visually provoked seizures tested positive for photosensitivity.

The standard test for photosensitivity is intermittent photic stimulation—a strobe light flashing at specified frequencies—while hooked up to EEG. Abnormal waves provoked by the photic stimulation are known as the photoparoxysmal response (PPR).  (To avoid triggering a seizure during the procedure, the flashing is halted as soon as any of these abnormal waves appear.)

Researchers have known for a long time that many people who test positive never actually experience photic seizures. The Buffalo study confirms this:  of 86 patients whose EEG yielded a PPR, just 13 (15.11 percent) reported having experienced visually triggered seizures. What’s new here is the finding that many people who test negative do actually experience these seizures.

The investigators, led by Novreen Shahdad, MD,  initiated their study after a patient with a clear history of seizures provoked by electronic screens did not test positive for photosensitivity. “With the increasing popularity of video games and parental concern of their predisposition for seizures,” the authors wrote, “there is a need to identify individuals at risk for PIS [photic induced seizures].”

Shahdad and her colleagues examined a Buffalo EEG database and found 129 patients between 1999 and 2013 who reported seizures triggered by TV, computer use, and video games. Of those patients, a total of 8 tested positive for photosensitivity. Thirty of the 129 patients had reported a history of video game seizures. Of those 30, only one showed a photosensitive response on EEG!

Photosensitivity is defined by researchers as the appearance on EEG,  in response to photic stimulation, of certain spike and wave patterns characteristic of epilepspy.  Note that the criterion for photosensitivity is not the occurrence of visually induced seizures in everyday life—it refers only to the strobe test.

The study concluded:

“In contrast to the general impression, our study did not find a significant association of a positive response to photic stimulation in patients with photic induced seizures (PIS). This association was seen only in 6.2% of patients with PIS. In addition, PPR on EEG was not associated with statistically significant increase of PIS. Hence we conclude that PPR cannot be used as an isolated predictor for PIS.”

I’ve previously raised issues about the accuracy of photic stimulation. More study is certainly warranted.


Nintendo, Activision, Ubisoft preview unsafe games at E3

The image shown in the upper left of this screen shot, from a flashing sequence in Nintendo’s Super Smash Bros., fails the seizure safety test. The graph on the right shows the brightness of the flash exceeding the safe limit.

The image shown in the upper left of this screenshot, from Nintendo’s Super Smash Bros., is one frame in a flashing sequence in  that fails the seizure safety test. The graph on the right shows the brightness of the flash exceeding the safe limit.

The 2014 E3 (Electronic Entertainment Expo) just wrapped up in Los Angeles with all the major game publishers previewing their upcoming releases. The big companies publishing these games have mammoth budgets and should be able to fund some quality control that supports the interest of public health. Apparently that line item is still not getting the focus it deserves.

Last week PCMag.com listed the 10 most anticipated games to be announced at E3. How many of them might trigger seizures in people with photosensitive epilepsy?

Destiny, a massively multiplayer first-person shooter game to be released in September 2014, is an entirely new game. It fails the safety test, too.

Destiny, a massively multiplayer first-person shooter game to be released in September, fails the safety test, too. Unlike the Nintendo game, it’s a completely new product. Both screen shots are taken from the Harding Flash and Pattern Analyzer, which tests images for seizure safety.

So far, 4 of them tested positive for seizure-inducing sequences–meaning they failed the Harding automated seizure safety test. This isn’t a final result because not all have enough “footage” available online for me to test adequately. Some may ultimately seem safe.

These tested as unsafe:

Super Smash Bros. (Nintendo)

Call of Duty: Advanced Warfare (Activision)

Destiny (Activision)

Tom Clancy’s The Division (Ubisoft)

In other words, the patterns, flashes, and/or red intensity of onscreen images produce the exact type of visual stimulation–that’s been carefully defined by researchers–that places viewers at risk of photosensitive seizures. People with a genetic predisposition for these seizures are vulnerable, whether or not they have ever experienced a seizure before, and whether they even know they have this genetic trait.

Nintendo’s Mario games have been triggering seizures for more than 20 years. Reports began surfacing in 1992 about seizures from Super Mario. As a result, a study on video game seizures published in 1999 used Super Mario World to test subjects known to be photosensitive. And a lawsuit was filed in 2001 by parents of a boy who had a seizure while playing Super Mario Kart.

But what about new games such as Destiny? A whole new game provides the perfect opportunity to create an entirely novel visual experience. Why not architect the whole thing keeping in mind the seizure hazard that persists in many games?

In sum, some of the video game industry’s biggest players are continuing to ignore safety guidelines, placing the public at unnecessary risk. I don’t know where the myth originated that games produced nowadays don’t produce seizures.


Disenfranchisement of reflex seizures ending?

The new definition of epilepsy makes it clear that reflex seizures "count" as evidence of epilepsy. In previous definitions, this was not explicity stated.

The new definition of epilepsy makes it clear that reflex seizures “count” as evidence of epilepsy. In previous definitions, this was not explicity stated.

A new definition of epilepsy published this week affirms that photosensitive and other reflex seizures qualify as “real” epilepsy. This clarification may eventually help increase awareness of seizures from video games and other electronic media.

Although reflex seizures have long been included in official classification schemes of epileptic seizures, they don’t fit cleanly into established categories of seizure types and epilepsy syndromes. In neurology training they are typically mentioned only briefly. And typically they are taken too lightly by doctors using the prevailing diagnostic criteria for epilepsy: at least two unprovoked seizures at least 24 hours apart.     

Because reflex seizures, by definition, are provoked by specific triggers, there’s confusion and most doctors have been reluctant to diagnose epilepsy in people whose epileptic seizures require an environmental provocation.  The authors of the new definition paper acknowledge this:

Under limits of the current definition, [a] patient might have photosensitive epilepsy, yet not be considered to have epilepsy because the seizures are provoked by lights…People with reflex epilepsies previously have been disenfranchised by the requirement that seizures be unprovoked. The inclusion of reflex epilepsy syndromes in a practical clinical definition of epilepsy now brings these individuals into the epilepsy community.” 

Diagnostic criteria under the new definition now include at least two unprovoked or reflex seizures at least 24 hours apart. The new definition also allows an epilepsy diagnosis after a single seizure–either unprovoked or reflex–if there is a high probability of recurrence.

I’ve written previously about the inconsistency inherent in using the criterion of “unprovoked” to diagnose epilepsy in people whose seizures happen only in response to sensory triggers such as flashing light. This thinking (along with the assumption that photosensitive epilepsy is very rare) has led to marginalization of reflex seizures in the research community and among clinicians as well. Marginalization means doctors have been underdiagnosing reflex epilepsy, researchers seeking funding pursue other topics to study, and the public and public policy makers are largely unaware of the public health issue of photosensitive seizures.

The practical clinical definition was developed by a 19-member multinational task force of the International League Against Epilepsy (ILAE), incorporating input from hundreds of other clinicians, researchers, patients, and other interested parties. I’m more than pleased that the ILAE is choosing to make it clear that reflex epilepsy deserves the same respect as other forms of the disease (the new definition paper characterizes epilepsy as a disease rather than a disorder). It’s fortunate that the chair of the ILAE task force that produced the new definition is Robert Fisher, MD, PhD of Stanford, lead author of the 2005 consensus paper describing seizures from visual stimulation as “a serious public health problem.” No doubt Dr. Fisher’s appreciation of the magnitude of the problem was instrumental in ensuring that the task force addressed it.

Not all epileptologists agree with all aspects of the new epilepsy definition–and Epilepsia has given them a voice as well, publishing half a dozen commentaries, all of which are available free online. I contributed a piece as well, providing a patient/family perspective.

Of course, it remains to be seen how long it will take for neurologists to shift their attitudes and diagnostic practices regarding reflex epilepsy. Perhaps the inclusion of reflex seizures in the epilepsy definition will help dispell the idea that reflex seizures are rare.


Removing seizure triggers doesn’t spoil the fun

A short video clip on the website of Vanderquest Limited simultaneously shows a music video both before and after changes were made for photosensitive epilepsy safety. Read on for a link to it.

Gaming fans who object to the concept of seizure-safe games have some major misconceptions about how their favorite games would look after seizure-inducing visuals are removed.

I’ve seen people in online forums threaten to stop their game subscription if the game’s images are made safe. These folks are assuming that making safety modifications to the graphics will mean “neutering” the game experience in a way that ruins their enjoyment. In fact, very minor changes to images, which can be pretty hard to detect, are often all that’s needed.

Thanks to extensive research that defined the characteristics of images that induce seizures, it’s possible to make small changes that interrupt any such seizure-generating sequences. For example, after changes are made to some video frames, the flash interval–more than 3 flashes per second–which can lead to a seizure in people with photosensitive epilepsy, no longer induces seizures.

Want some proof?

NOTE: For those with visual sensitivity, before you click on the upcoming link to side-by-side videos, know that you should be able to view the page safely because the problem images aren’t very large. If you’d prefer not to risk it, you might want to step back farther from your screen or cover the left side of your screen, because that’s where the problem images are.

Now click to see the side-by-side images of a music video running in its original form (with safety violations) and after modifications were made to comply with seizure safety guidelines (in the UK, they’re requirements, not guidelines). The changes are very subtle! Can you find them? As you’ll see in the modified version, even visual sequences that contain some flashes and quick cuts can therefore pass the safety test. Basically, portions of some flashing sequences (9 instances) have been altered or removed, which does little to change the overall viewing experience. Edits to the video that allowed it to be broadcast were done within a single day by London-based post-production firm Vanderquest Limited.

Readers familiar with the Harding Flash and Pattern Analyzer that I routinely use to test video material for seizure safety will recognize the HFPA results shown beneath both versions of the music video. Although the original, uncorrected official version could not be broadcast in the UK due to regulations barring seizure-inducing material from being shown there, it lives on on YouTube.

Imagine these types of edits to the user interface of a video game. Exactly how do they ruin the gaming experience?! Or artistic expression?


Can handheld games trigger seizures?

Nintendo's 3DS console

Nintendo’s 3DS console

Think the screen of a handheld game is too small to provoke seizures?

It isn’t. Games on the 2.9 inch screen of Nintendo’s Game Boy Advance SP provoked quite a few seizures in my daughter when she owned one ten years ago. 

Nintendo’s current handheld is the popular 3DS console, which has a 3.5 inch screen. I recently tested some 3DS games to ascertain their seizure safety.  

The rule of thumb (as it were) is that, for flashing and patterns to trigger seizures, the provoking image must take up at least one fourth of an individual’s visual field. It’s not unusual for kids to hold their portable games at close enough range for that small a screen to fill that much of their total view. Incidentally, although concerns were raised when the 3DS was introduced three years ago, there isn’t any conclusive evidence that 3D effects increase the risk of seizures in people who are photosensitive.

The IGN.com website recently identified the 14 most anticipated 3DS games for 2014 release. Here’s how they fared when tested for compliance with guidelines for preventing visually induced seizures; 6 of the 14 failed, and an additional 5 came close. Tests were done using the Harding Flash and Pattern Analyzer.

Here is how these highly anticipated 3DS games performed as far as meeting image safety guidelines for preventing photosensitive seizures:

Professor Layton & Azran Legacies, One Piece Romance Dawn, Mario Golf World Tour, Lego Movie, Yoshi's New Island, Super Smash Brothers, Mario Party Island Tour, CHantae & the Pirate's Curse, Retro City Rampage, Professor Layton vs Phoenix Wright, Kirby Triple Deluxe, Chi Bi-Robo Photo Finder, Bravely Default, Conception II

14 Big 3DS Games of 2014, published January 30, 2014 on IGN.com

Yes, there are seizure warnings on all game packages, but the warnings are pretty worthless for consumers. A year ago I posted about Nintendo being fully aware of, but publicly downplaying, the risk of seizures from its games.


Images in race car games can provoke seizures

racing games driver's view (580x305)

Rapidly changing scenery can include image sequences that trigger seizures.

Parents concerned about their kids playing shooter and adventure games that feature a lot of violence may feel more comfortable with the racing game genre. But these games aren’t necessarily harmless–because they contain lots of images with the potential to trigger seizures in those with photosensitive epilepsy.

Problem image sequences in racing games involve lights and patterns in a variety of scenes, such as:

  • close-ups of rotating wheels/tires
  • revolving scenery as seen by driver when cars do airborne flips
  • collision impact shock, lighting change, and vibrations
  • fast-moving patterns of quickly changing views of bridges, tunnels, and landscape features

I tested clips from 7 recommended racing games listed on a site that reviews video games, movies, music, and other media, and advises parents on their content. The potential of particular games (or any other media) to provoke seizures is absent in product reviews on this site and others.

During a rapid airborne rollover in Dirt 2, the road appears at the top of the screen. This sequence of flipping images violated  seizure safety guidelines.

During a rapid airborne rollover in Dirt 2, shown in this screen grab, the road appears at the top of the screen. This sequence violated seizure safety guidelines.

Of the 7 games, 5 contained seizure-provoking sequences. The very fast-paced action and inevitable crashes provide many opportunities for visual overstimulation, although some of the games with equally exciting visuals did not actually fail the seizure safety test.

My results were arrived at using the Harding Flash and Pattern Analyzer, a tool for determining compliance of video images with guidelines for prevention of visually induced seizures. Your results may vary:

  • settings on your monitor affecting brightness, contrast, and other visual effects can raise or reduce the demands on the visual cortex
  • factors such as fatigue, illness, alcohol, etc. temporarily lower an individual’s seizure threshold
  • sitting farther away from the screen and taking frequent breaks can lessen the images’ visual impact

Although players will encounter scenes in the game that I didn’t analyze, making adjustments such as those above can significantly reduce an individual’s risk of visually provoked seizures.

Here are the results from the Harding Flash and Pattern Analyzer:

Driver - San Francisco, Split Second, Grid 2, Forza Horizon, Wipeout 2048, F1 2011, Dirt 2

The fast action of racing games means higher seizure risks.

Methodology:  I ran multiple video clips through the analyzer, including official announcement trailers and gameplay clips uploaded by users. If the initial test for a game didn’t show safety violations, I continued testing up to an additional 6 – 8 clips for each game before moving on (or until a failure occurs, if that came first).

I’ve previously tested multi-player, role-playing games (MMORPGs) and first-person shooters. Overall, based on my samplings of these genres and racing games, MMORPGs are least likely to trigger seizures.


Task force may look into video game seizures [updated]**

The Massachusetts State House in Boston, where a bill was filed to investigate video game seizures as a public health issue.

The Massachusetts State House in Boston, where a bill was filed to investigate video game seizures as a public health issue.

Massachusetts State Rep. Ruth Balser has filed a bill calling for a working group to examine video game seizures as a public health issue in Massachusetts. The bill has been assigned to the Joint Committee on Public Health, where Rep. Balser is a member. I had met with her a couple of years ago to share my concerns about video game seizures as an underrecognized public health problem, particularly in young people.

To date, state legislatures have considered proposals to limit access by minors to “mature” and violent game content, and one legislator in New York State has proposed that signs be posted warning of possible seizures wherever video games are sold or rented. There have been no proposals like this one in Massachusetts, where the issue of concern is the public health problem of the seizures precipitated by video games. It’s my hope that this can be investigated and discussed in a straightforward way without all the emotion that gets people so polarized whenever the game industry and its supporters are asked to respond to concerns.

The goal of this initiative is not to spoil anybody’s leisure time activities, or put game developers out of business, or take away anybody’s right to play games. It’s to reduce the risk of seizures while consumers play video games. The issue needs public discussion, and a thoughtful report prepared in the interest of public health is a good way to start.

I’m learning about the process of enacting legislation in this state. The bill was formally introduced to the Joint Committee on Public Health in September: I provided articles on photosensitive epilepsy and letters of support for the bill, and made a very brief oral statement.

The next step for the bill involves the Committee’s Director of Research, who will review the background information and support letters I provided. He will then recommend to the Committee’s House and Senate Chairs whether the bill should receive consideration by the full committee. In December, before he makes that recommendation, I will meet with him to discuss the issues and answer any questions. Stay tuned–in the coming weeks I’ll report on the progress of Mass. House bill H1892. 

**3/31/14 update: There won’t be any further progress on the bill during the current legislative session (that ends at the end of the year). I’ve learned that this effort requires a lot more work than an individual can contribute…it was a valuable experience, and the door is open to file a revised version of the bill in future legislative sessions.


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