--- title: How Someone Got Seizures from Solving Sudoku Puzzles description: A team of doctors discuss one of their more puzzling cases: a man who had a seizure when he tried to solve a Sudoku game. canonical: https://time.com/4078049/seizure-sudoku-puzzles/ author: Mandy Oaklander article:opinion: false article:content_tier: free article:published_time: 2015-10-19T15:07:24.000Z article:modified_time: 2023-12-14T00:17:40.000Z article:section: Health og:title: How Sudoku Caused This Man's Seizures og:description: A team of doctors discuss one of their more puzzling cases: a man who had a seizure when he tried to solve a Sudoku game. og:url: https://time.com/4078049/seizure-sudoku-puzzles/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltea689a6e2e63aa71/698868d95f570f3432b1de76/sudoku.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 2560 og:image:height: 1440 og:image:alt: sudoku puzzle og:type: article twitter:card: summary_large_image twitter:title: How Sudoku Caused This Man's Seizures twitter:description: A team of doctors discuss one of their more puzzling cases: a man who had a seizure when he tried to solve a Sudoku game. twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltea689a6e2e63aa71/698868d95f570f3432b1de76/sudoku.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 ---  # How Sudoku Caused This Man's Seizures > Sponsored content. 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Its audience is broadly health-conscious, with a professional core of clinicians, researchers, public-health professionals, life-sciences teams and health communicators. ### Sources * TIME Newsletters: [time.com/newsletters](/c/time-nl-health-2026q3/newsletters?i=e44f2499-272e-4b8a-beac-130d73c15392&cr=time-nl-health-2026q3-v1) ## Video: Inside the Mind of a Sudoku Master [Watch (HLS stream): Inside the Mind of a Sudoku Master](https://cdn.jwplayer.com/manifests/yzPjheT7.m3u8) (5:59)  _Published 2009-11-15. Sudoku whiz Thomas Snyder squares off against his friend and former puzzle champ at the National Sudoku Championship in Philadelphia_  by [Mandy Oaklander](https://time.com/author/mandy-oaklander/)  ## Mandy Oaklander Oaklander is a senior editor at TIME. Updated: Dec 14, 2023 12:17 AM UTCPublished: Oct 19, 2015 3:07 PM UTC  by [Mandy Oaklander](https://time.com/author/mandy-oaklander/)  ## Mandy Oaklander Oaklander is a senior editor at TIME. Updated: Dec 14, 2023 12:17 AM UTCPublished: Oct 19, 2015 3:07 PM UTC In a new [report](http://archneur.jamanetwork.com/article.aspx?doi=10.1001/jamaneurol.2015.2828) published in _JAMA Neurology_, a team of doctors discuss one of their more puzzling cases: a man who had a seizure when he tried to solve Sudoku. The patient was a 25-year-old man who had been buried by an avalanche during a ski trip and endured 15 minutes without enough oxygen, a condition called hypoxia. After, he developed involuntary muscle jerks of his mouth when he tried to talk and his legs when he tried to walk—but his arms didn’t seem to have been affected. That changed weeks later, explain the authors, the patient’s team of doctors from the University of Munich in Germany. “He was in the rehabilitation clinic, and he was bored, so he started doing Sudokus,” says co-author and neurologist Dr. Berend Feddersen. When the right-handed patient tried to solve a Sudoku puzzle, he experienced quick muscular contractions—clonic seizures—of his left arm. ([Here’s a video of the patient solving Sudoku.](http://archneur.jamanetwork.com/multimediaPlayer.aspx?mediaid=11873095)) The seizures stopped instantly when he stopped the game. Feddersen had never seen anything like it, and nothing existed in the scientific literature about Sudoku-caused seizures. But the authors explain it as a case of reflex epilepsy: seizures that can be triggered by external stimuli like playing games, reading, doing math, touching and bathing in warm water. For this patient, Sudoku, which involves ordering numbers one through nine in a square grid, was such a trigger. Reading, writing and even math alone didn’t have an effect. But visualization-spatial tasks, in which the patient sorted numbers in ascending order, did. “When he solves Sudoku, one of his strategies is to arrange the numbers in some 3D manner,” Feddersen says. “That’s very interesting, because when I do Sudoku, I just make trial and error.” After analyzing his brain imaging data, the patient’s doctors concluded that the oxygen deprivation caused damage throughout the brain, especially to the U-fibres found all around the brain that contribute to inhibition. “When these kinds of neurons are dying, then you have not enough inhibition, so a loss of U-fibres leads to an overactivation,” Feddersen says. “For him, luckily it was this kind of Sudkoku thing which was the activation, and not another one he does in his daily life.” When the patient stopped solving Sudoku puzzles, the seizures stopped, too. “\[He\] has been seizure free for more than 5 years,” the study authors write. ## Transcript >> It's hard to describe what I actually do besides focus on the puzzle, find what I think is the right starting point and then just start away and not stop until I can say done and I'm finish. >> Thomas Snyder is widely considered the best Sudoku player in the world. He's got two world titles and a national title to prove it. This year, at the National Sudoku Championship, his toughest competitor happens to be his good friend, Wei- Hwa Huang. >> I have the type of brain that's always sort of racing. I always want to be thinking about something. There's a lot of people who much prefer times where they're not thinking about anything. And if you put me in an environment like that, I'll be like bored to tears. >> Last year at the US Sudoku Tournament, Thomas beat me on every single puzzle except one of them. >> It was the final round of the 2008 Championship that left the sour taste in Thomas' mouth when he lost the title to Wei- Hwa by a nail- biting 28 seconds. >> Twenty- nine, twenty- eight depends-- >> Who's out there. >> I won about 30 but, you know-- >> Half minute, yeah. >> Oh, okay. >> Tonight, Thomas and Wei- Hwa are sharing a hotel room and staying up late to play some games and, of course, all the few last minute puzzles. But tomorrow, they will become competitors. >> Welcome to the 3rd National Sudoku Championship. >> And probably two or three people I'm quite and done. >> Wei lost one of them. >> Tammy McLeod is another, the software engineer who's been in the national finals every year. >> There's always the unknown. That's the last case. >> They are part of the-- first time we've never heard of. >> On your mark, get set, solve. >> The tournament is divided into three categories; beginner, intermediate and advanced. There are three rounds in which each puzzler has 30 minutes to complete three Sudoku grids. Nine minutes into the first round, Thomas has finished all three puzzles, heads above everyone else. >> Well, the first round is always a practice because, you know, Thomas is gonna qualify in the first round. >> It was a tough round for Wei- Hwa, it's a tough round for other people. I expect some faster times by the end of the day. >> The game of Sudoku has been around for years. It began as a numbers puzzle in the United States and in 1986, it was adjusted by a Japanese company, Nikoli and renamed Sudoku. But it wasn't until Wayne Gould brought it to the times of London in 2004 that it became an international phenomenon. >> Sudoku is great. You can explain it in 10 seconds to anybody with a single sentence. >> A sentence that goes something like this. Fill in all empty cells of the grid with numbers from one to nine so they don't appear more than once in each row, column and inside the three by three block. >> When you spend 10, 15, 30 minutes on a Sudoku puzzle, you get wrapped up in this world, you forget everything else and when you're done and you feel relaxed and refreshed and ready to go back and tackle everything else in a row. >> Looking around this tournament, it is clear that puzzle has appealed to people of all ages. From 93- year- old Edward Radvill to 8- year- old Jack Newman. >> All of a sudden, I got really addicted to it and I can't stop doing it. It's really fun. >> As Jack finishes his first puzzle in the beginner division, Wei- Hwa races through round two and three. But it's not his year. He loses both rounds, first to a veteran puzzle solver Tammy McLeod and then to the unknown Eugene Varshavsky. >> Combinatin of being emotional at a moment and thrill and everything of I know. >> Eugene walked off the street today and registered halfway through the tournament. The hooded stranger only completed the third round and in one shot qualified to the finals. >> The finals are very different kind of experience in solving. One thing I tried to do this, I adult myself a little similar sort of white board on a piece of shower board in my room or some [ unk ] tapes so I could recreate the experience. -[ unk ], on your mark, get set, solve. >> After seven and a half minutes, Thomas completes his grid. He pauses and enjoys the moment. But it doesn't last long as Tammy finishes her puzzle, Thomas notices a mistake. >> And then the 4 and 6 in the bottom could flip. >> Yes. That's correct. >> He notifies the judges before they announce an official winner and he's the first to congratulate Tammy on her victory. >> I looked my last three digits-- >> Sometimes you're gonna be too fast. >> I was kind of been shocked for a few minutes then someone asked me if I was not happy about it like, I think I was just too stunned. >> Unfortunately, the tournament didn't end with this active good sportsmanship. You remember Eugene Varshavsky, the dark horse who surprised everyone in the third round. Well, he might be a cheater. Thomas Snyder and others got suspicious when he only managed to fill in three numbers n his final puzzle. He also happens to have the same name as the name accused of cheating in the World Open Chess Tournament in Philadelphia two years ago. TIME couldn't reach Eugene for comment. But the Philadelphia Inquirers is launching an investigation. 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