Diagnostic dilemma: Man’s sudden attack was caused by Sudoku

Patient: 25-year-old male living in Germany

Symptoms: During a ski trip in November 2008, a man was knocked unconscious by an avalanche and was buried under snow for 15 minutes. While trapped, his body tissues became starved of oxygen, causing a condition called hypoxia. Berend Feddersen, a neurologist at the University of Munich in Germany and lead author of a report on the incident, previously told Live Science that his friends rescued him and began CPR immediately after he was freed from the snow. He was then taken to the hospital.

The hypoxia caused the man to suffer movement disorders, causing uncontrollable spasms in the muscles in his legs and mouth when walking and talking. He never experienced muscle spasms like this in his arms.

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What happened next: The man was hospitalized and then transferred to a rehabilitation facility. While at this center, he started doing Sudoku puzzles. This was a regular pastime even before my injury.

As he solved Sudoku, the muscles in his left arm twitched repeatedly. However, these movements stopped as soon as he stopped working on the puzzle.

Diagnosis: The man appeared to be having a clonic seizure (repeated jerky movements) in his arms while playing Sudoku, so the medical team performed a brain scan to better understand what was going on.

Electroencephalography, which measures activity on the surface of the brain, revealed that the patient was experiencing a right parietal-centered seizure pattern. This means that the seizures originate in the middle and parietal areas of the right hemisphere of the brain. The MRI showed no evidence of any disease or abnormality that could be causing this seizure activity.

The medical team then performed a functional MRI (fMRI) test while the patient was solving Sudoku. This type of scan tracks activity throughout the brain via blood flow. Scans revealed “widespread activation,” but particularly in the parietal-central cortex, doctors wrote in a case report. Further examination using a type of MRI called diffusion tensor imaging, which maps the brain’s white matter fibers, showed that this brain region had fewer inhibitory fibers.

When the inhibitory fibers that help suppress brain cell activity were lost, activity in the nerves running through the patients’ left arms increased threefold. Doctors wrote that the hypoxia the man experienced during the avalanche was the “most likely” cause of the injury.

Hyperactivation of the right central parietal cortex then triggered focal epileptic seizures, which are seizures focused in one discrete area of ​​the brain. Specifically, the patient had reflex epilepsy, in which seizures were triggered by certain stimuli, such as certain lights or music.

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In this case, a three-dimensional image the patient imagined while solving Sudoku triggered the attack, Feddersen said. The patient did not experience clonic seizures when reading, writing, or arithmetic. But doctors may induce seizures by giving the men other visual-spatial tasks, such as arranging random strings of numbers from lowest to highest.

Treatment: The patient was prescribed antiepileptic drugs and the seizures stopped. According to the report, as of 2015, he had not had a seizure for more than five years. He also underwent physical therapy to relieve the spasms he experiences when walking and talking.

He also gave up trying to solve Sudoku puzzles.

Characteristics of this case: Approximately 3.8% of people will develop epilepsy in their lifetime, and approximately 4% to 7% of these will experience reflex seizures. Although this was the first known case in which a Sudoku puzzle caused a seizure, a common type of reflex epilepsy is called “praxis-induced”, in which visual motor tasks such as chess or cards trigger muscle spasms.

For example, in 2015, doctors reported cases of five men with epilepsy in China who had seizures caused by playing the ancient Chinese game Zipai. These men were between 19 and 44 years old, and their seizures stopped when they avoided playing Zipai. Similarly, in January 2025, doctors in Taiwan reported on 30 patients who developed reflex seizures after playing mahjong.

For more interesting medical cases, check out our Diagnostic Dilemma archives.