ABC News Specials Medical Mysteries Series-Episode #6

Medical science has progressed exponentially in recent times, but scientists are still left with unanswered questions when it comes to the human body. "Medical Mysteries" looks at some of the rarest disorders and syndromes in medicine today. How could a father not recognize his own children? It's a condition known as face blindness, but people who have it can see faces perfectly well, they just can't process what people look like. ABC News reports on the neurological disorder Prosopagnosia, where people can't distinguish faces -- including their own. Until recently, most Prosopagnosia cases have been the result of stroke or brain injury, but now researchers say there may be a single gene to blame. Then, for most couples their wedding day is unforgettable, but just three days after Sean McNulty married his wife, Amy Harrison, he couldn't remember anything from his life. Sean and Amy were leaving for their honeymoon when he vanished from the airport. After days of searching, Sean was discovered by police wandering aimlessly near an abandoned hotel. But his disappearance was only the beginning of a baffling journey. He had forgotten everything from his past, including his marriage to Amy. Diagnosed with a severe case of amnesia, Sean had to get to know Amy all over again. Can doctors train a tongue to do what eyes can't? ABC News reports on a revolutionary device that could make it possible for blind people to navigate without a cane or a seeing-eye dog. The device is placed on the tongue to emit a slight pulse or shocking sensation as the blind person approaches obstacles. The pattern of shocks on a blind person's tongue mimics the shapes they are approaching.

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