For some of us, solving sudoku puzzles can be a real headache but for a 25-year-old German man, his passion for sudoku led to frequent seizures.
The right-handed physical education student was buried by an avalanche during a ski tour some years back.
For 15 minutes, he did not get sufficient oxygen (called hypoxia) which irreversibly damaged certain parts of his brain.
Owing to this, he developed involuntary myoclonic jerking (brief, involuntary twitching of muscles) of the mouth induced by talking and of the legs by walking.
"He had to be resuscitated, but was extremely lucky that he survived," said lead author Berend Feddersen from the University of Munich, Germany.
Weeks later during the rehabilitation when he was trying to solve Sudoku puzzles, he developed clonic seizures (rapid contractions of muscles) of the left arm.
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Strangely, the seizures stopped when the Sudoku puzzle was discontinued.
"In order to solve a Sudoku, the patient used regions of his brain which are responsible for visual-spatial tasks. But exactly those brain parts had been damaged in the accident and then caused the seizures once they were used," Feddersen explained.
The authors suggest that oxygen deficiency most likely caused some damage to the brain.
The patient stopped solving Sudoku puzzles and has been seizure-free for more than five years.
The case was detailed in a paper published in JAMA Neurology, a Journal of the American Medical Association.