While sleeping overnight at a hotel in 2006, Canadian tennis star Peter Polansky saw a dark figure with a knife standing by the doorway to his room. Still asleep, the 17-year-old athlete bolted out of bed, and in an effort to escape the phantom intruder, kicked the glass out of his window and jumped out. He plummeted three stories and landed in a courtyard, miraculously escaping death.
Though stories like these are rare, as many as 9 percent of adults are affected by so-called parasomnias, in which a person, technically asleep, engages in complex and bizarre activity. Parasomnias come in many forms, among them sleepwalking, sleep talking, and night terrors. Researchers still do not understand the origins of these odd behaviors. With rare exceptions, no one has been able to trace parasomnias to an obvious problem, such as an anatomical fault or chemical imbalance in the brain. Nonetheless, sleep disorder ...
