"It sounds crazy. But (there are) actually one of a number of people who've miraculously developed artistic, musical, or mathematical abilities as a result of a brain injury. There's Orlando Serrell, who was struck in the head with a baseball as a 10-year-old and found he could remember the weather for each day following his accident. There's Derek Amato, who woke up after hitting his head at the bottom of a pool and became a master pianist at 40, despite lacking any sort of musical training. There's Alonzo Clemens, whose verbal and cognitive abilities stopped developing at the age of three due to a head injury but who can assemble incredibly detailed sculptures of animals in a matter of minutes."
http://www.theatlantic.com/health/archive/2012/05/eureka-when-a-blow-to-the-head-creates-a-sudden-genius/257282/