Sudoku puzzles can be brainteasers, but one man's brain had an unusual response to solving the numerical grid puzzles: He developed seizures. 
 
 The 25-year-old German man didn't always react this way to Sudoku, according to a new report of his case. His problems began after he was trapped in an avalanche during a ski trip. The young man, a physical education student, had been skiing with a friend in November 2008 when an avalanche occurred on the mountain. 
 
 The avalanche buried the man in the snow and knocked him unconscious, according to the case report. But he was fortunate to have been skiing with a buddy who was a paramedic, and his friend rescued him and started CPR immediately, said Dr. Berend Feddersen, a neurologist at the University of Munich in Germany, and the lead author of the case report published today (Oct. 19) in the journal JAMA Neurology. 
 
 The man suffered a ruptured spleen and hip fracture, Feddersen said. In addition, while he was buried under the snow, his body tissues and brain got too little oxygen, a condition known as hypoxia. 
 
 As a consequence of his brain being deprived of oxygen for 15 minutes, the man developed myoclonic jerks, which are sudden muscle twitches. These twitches occurred in the muscles of his mouth when he talked, and they also occurred in the muscles of both of his legs when he walked. [See Video: Man Has Seizures While Doing Sudoku] 
 
 In the hospital, the man started having a type of seizure called spontaneous tonic clonic seizures in his left arm, Feddersen told Live Science. This type of seizure involves the muscles stiffening and then jerking rapidly and rhythmically. The doctors prescribed anti-epileptic medication to keep the seizures under control, Feddersen said. 
 
 Sudoku-induced seizures 
 
 A few weeks later, after the man was moved from the hospital to a rehabilitation facility to continue his recovery, he attempted to solve a Sudoku puzzle, an activity he enjoyed doing in his free time. 
 
 But while doing the puzzle, he again began having clonic seizures, or muscle twitches, in his left arm. 
 
 Eventually, the doctors figured out that these seizures were triggered because the man had a very intense three-dimensional imagination that activated whenever he solved a Sudoku puzzle. Imagining the numbers three-dimensionally allowed him to sort them and put them in sequence, Feddersen told Live Science. 
 
 The seizures did not occur when the man completed other types of math problems, or while he was reading, Feddersen said. 
 
 The reason the seizures began only after the avalanche was because the hypoxia had resulted in the death of inhibitory fibers, which slow down brain signaling, in the right centro-parietal region of the man's brain. 
 
 Normally, this area of the brain is activated when 3D imagination is used. But with fewer inhibitory fibers in this region, when the man used his 3D imagination, it led to an overactivation of this brain region, which resulted in clonic seizures in his left arm. 
 
 The doctors even found that when the man had very strongly activated his 3D imagination while solving Sudoku, the clonic seizures in his left arm were much more intense, Feddersen said. 
 
 "When he stopped this 3D imagination, the seizures stopped immediately," he noted. So, the man had no choice but to give up Sudoku. 
 
 Feddersen last saw the man in November 2014. He was still affected by the myoclonic twitches brought on by talking and walking, but these symptoms have improved with physical therapy, he said. 
 
 The man has been seizure-free for more than five years, thanks to taking anti-epileptic medication regularly — and steering clear of Sudoku. 
 
 Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science. ||||| Solving sudoku puzzles led to seizures in a young German man, say scientists from the University of Munich who wrote about the unusual medical tale in JAMA Neurology. 
 
 The 25-year-old man, a physical education student, had survived being buried just weeks before by an avalanche during a ski trip. Deprived of oxygen for 15 minutes, he developed muscle jerks when he tried to speak and walk. While in the hospital, he was trying to work out a sudoku puzzle when he began to experience clonic seizures of his left arm, which had not been injured in the accident. Clonic seizures involve repeated jerking of the muscles. When the patient stopped trying to solve the puzzle, oddly, the seizures ceased. 
 
 In their report about the unique case, Dr. Berend Feddersen and colleagues explained that the patient experienced reflex epilepsy which is characterized by seizures induced by external stimuli such as reading, making calculations, touching, a warm bath, playing games, noise -- or in this case, a sudoku puzzle. 
 
 To solve a sudoku puzzle, every digit from 1 to 9 needs to appear in each of 9 vertical columns, in each of 9 horizontal rows, and in each of 9 boxes. The way the patient figured out answers to the puzzle was by visualizing solutions in 3D, but because his brain was damaged by the accident, this triggered reflex epilepsy. 
 
 While the case study focused on sudoku as the trigger, the patient told CBS News in an email that other things can set off his seizures as well. "Take crossword puzzles ... excel sheets ... they all share something: horizontal and vertical lines and the brain must calculate, then focus on one certain spot (to write something down) PLUS the fingers have to move. I think that this combination causes the real problem," he said. 
 
 Why would this happen? "In our patient, hypoxia [oxygen deprivation] most likely caused some diffuse, widespread damage," Feddersen wrote. 
 
 The brain consists of brain cells connected by fibers, explained Mayo Clinic neurologist Dr. Elson So, an epilepsy specialist. 
 
 "We can look at the brain as a network system. There are some centers for mathematical concepts and others for language. The authors have shown with some evidence that the fibers connecting the centers were damaged," So said. 
 
 So explained that not all the fibers in the brain play a role in "activating" specific functions; they also play a role in keeping other things down. "Every complex system needs an activating and deactivating systems. Everything in moderation." 
 
 He said the fibers that are supposed to moderate the excitation for mathematical concepts and exercises had become hyper-activated because of damage to fibers that should be tempering the excitation. 
 
 "It's a very interesting finding and a nice demonstration for what is basically reflex epilepsy," said So. 
 
 Fortunately for the patient in Germany, kicking his sudoku habit was enough to stop the seizures. 
 
 "Our patient stopped solving sudoku puzzles and has been seizure free for more than five years," Feddersen wrote. 
 
 In addition, the man said, "I stay away from crossword puzzles ... Once in a while I play scrabble, but unfortunately problem [is] the same. I don't miss it. There are so many things that I miss (in contrast to my old life), sudoku and crossword puzzles are the least important ones." ||||| In what is believed to be a world first, scientists have reversed brain damage in a toddler that drowned in a swimming pool. Using oxygen therapy, scientists were able to restore her ability to walk and talk just months after the accident, in which she spent 15 minutes submerged in a swimming pool and two hours where her heart did not beat on its own. 
 
 The accident took place in February 2016. Two-year-old Eden Carlson had managed to get through a baby gate and fall into the family swimming pool and was in the 5 degree Celsius water for up to 15 minutes before being discovered. 
 
 Read more: First Double-Hand Transplant Allows Child to Eat, Dress and Write 
 
 After being resuscitated and treated in hospital for just over a month, she was unresponsive to all stimuli. She was immobile and constantly squirmed and shook her head. MRI scans showed deep injury to the brain’s gray matter, as well as loss of white and gray matter. 
 
 In a bid to reverse the brain damage, researchers at the LSU Health New Orleans School of Medicine and the University of North Dakota School of Medicine began treating her with two types of oxygen therapy. 
 
 This includes normobaric oxygen therapy, where levels of oxygen given are the same as at sea level, and hyperbaric oxygen therapy (HBOT), where they are given pure oxygen at pressures higher than that of the atmosphere within a special chamber. 
 
 Fifty five days after the drowning accident, doctors started giving Eden normobaric oxygen for 45 minutes twice per day. This appeared to make her more alert and awake, and she stopped squirming. She started laughing more and was able to move her arms and hands, and grasp with her left. Scientists also noted eye-tracking movements and some speech. 
 
 Read more: A New Theory on Cancer—What We Know About How It Starts Could All Be Wrong 
 
 After 78 days, Eden began HBOT therapy, with 45 minute sessions five days per week for four weeks. After 10 sessions, her mother said she was almost back to normal other than motor function. After 39 sessions—coupled with physical therapy—Eden was able to walk and her speech had returned to normal. Her cognitive abilities had improved and motor function was almost restored to pre-drowning levels. 
 
 An MRI scan a month after the 40th HBOT session showed almost complete reversal of the brain damage initially recorded. Researchers believe the oxygen therapy, coupled with Eden having the developing brain of a child, had activated genes that promote cell survival and reduce inflammation—allowing the brain to recover. The case report is published in the journal Medical Gas Research. 
 
 Paul Harch, who treated Eden, said in a statement: “The startling regrowth of tissue in this case occurred because we were able to intervene early in a growing child, before long-term tissue degeneration. Although it’s impossible to conclude from this single case if the sequential application of normobaric oxygen then HBOT would be more effective than HBOT alone, in the absence of HBOT therapy, short duration, repetitive normobaric oxygen therapy may be an option until HBOT is available." 
 
 Concluding, the researchers say that to their knowledge, this is the first reported case of gray matter loss and white matter atrophy (types of brain damage) reversal with any therapy and that treatment with oxygen should be considered in similar cases. “Such low-risk medical treatment may have a profound effect on recovery of function in similar patients who are neurologically devastated by drowning."
– A 25-year-old German skier survived an avalanche that buried him without oxygen for 15 minutes, thanks in no small part to his paramedic ski buddy, who rescued him and started CPR immediately. But the lack of oxygen to his body tissues and brain (called hypoxia) took a toll, notes Live Science, and University of Munich researchers report in JAMA Neurology that it manifested in a quite unusual side effect. First, he developed muscle jerks brought on by walking and talking, and at one point in the hospital he started a Sudoku puzzle, and the muscles in his left arm—which was not injured—began to spasm in what the doctors called "clonic" seizures, reports CBS News. "We can look at the brain as a network system," says Mayo Clinic neurologist Dr. Elson So, who was not involved in the research. "There are some centers for mathematical concepts and others for language. The authors have shown with some evidence that the fibers connecting the centers were damaged." Thanks to this damage, the fibers that control excitation for mathematical concepts and 3D thinking were essentially hyper-activated, and because the patient visualized solutions to Sudoku puzzles in 3D, the activity triggered epilepsy. Five years later, physical therapy improved the twitches brought on by walking and talking, and he's steered clear of seizures altogether thanks to epilepsy meds—and avoiding Sudoku completely. (Epilepsy may have fueled Chopin's hallucinations.)