NPR talks about Musicians

Listen: Say What? Musicians Hear Better
Musicians have years of training in listening to sounds. For example, their brains are trained to hear the sound of their own instruments even though other instruments may be playing at the same time. This training reshapes the brain and builds mental muscle in auditory processing and attention skills. Because these are the very skills that are often weak in children who struggle with language and reading, researchers believe that musical training may offer a real solution. Listen to NPR's Say What? (3:56)

And here's more good news:
It may not be good news for kids who don't want to experience a forced march to piano lessons, but it is good news for those who like to believe that skill in the arts can be acquired and does not entirely have to be foisted upon you by an accident of birth.
British researchers have found that areas of the brain related to auditory and motor skills grew in six-year-olds who studied music for 15 months, and not in those who didn't.
It's no secret that school arts programs are eternally imperiled, but it will be interesting to see what it contributes to that debate to have better evidence that, particularly for kids who can't afford private lessons, a lack of exposure to music in school may literally make for a smaller mind.