It's an interesting fact that severe brain injuries rarely, but sometimes, reveal remarkable talents in people that they never had before. The Atlantic has an interesting article thinking about the problems that fact raises.
Let me just note, though, that these problems disappear if you adopt the view of consciousness that I have sometimes advocated here. If consciousness is received by the brain rather than produced by it, an adjustment to the brain will receive a different part of the signal. Think of an old television set, when we used to broadcast TV through the air. The whole of television was in the signal, invisible, impossible to notice without a system that was structured in just the right way.
With such a system, though, you would find yourself watching a baseball game. But that wasn't the whole of the signal: retune the receiver, and you'd be watching a Western or a soap opera. All of it was there: it was how you tuned the receiver that determined what you got.
By the same token, if you gave the TV a good whack, sometimes you'd find that the signal became rather fuzzy. But sometimes it would improve! Sometimes it was just that whack that would bring the picture into extraordinary focus.
Of course, whack it hard enough and you might end up trying to show two programs at once; or, in fact, you might break the mechanism that was capable of receiving the signal. In that case you'd end up with a piece of junk that was once a television, a physical object now insensitive to the invisible signal in the air.
If that's the way consciousness works -- that is, if there is a unitary consciousness that our individual minds express individually because we are uniquely tuned to it -- then this phenomenon is no surprise at all. Make a significant adjustment to the manner in which the brain is tuned, and you will receive a different part of the signal.