This case report describes a patient who had hypoxia and posthypoxic intention myoclonus and subsequently developed clonic seizures while solving sudoku puzzles.
A 25-year-old right-handed physical education student was buried by an avalanche during a ski tour, resulting in 15 minutes of hypoxia. He developed posthypoxic intention myoclonus with involuntary myoclonic jerks of the mouth induced by talking and of both legs by walking. Both arms were unaffected. Weeks later when the patient was trying to solve sudoku puzzles, which he imagined in a 3-dimensional manner, he developed clonic seizures of the left arm associated with a right centroparietal seizure pattern on electroencephalography (Figure 1; eFigure in the Supplement). The unilateral clonic seizures stopped immediately when the sudoku puzzle was discontinued. To solve a sudoku puzzle, every digit from 1 to 9 must appear in each of the 9 vertical columns, in each of the 9 horizontal rows, and in each of the 9 boxes.