Scientists have uncovered the first concrete evidence that playing music can significantly enhance the brain and sharpen hearing for all kinds of sounds, including speech.

"Experience with music appears to help with many other things in life, potentially transferring to activities like reading or picking up nuances in tones of voices or hearing sounds in a noisy classroom better," researcher Nina Kraus, a neuroscientist at Northwestern University, told LiveScience.

These new findings highlight the importance of music classes, she said.

"Music classes are often among the first to be cut when school budgets get tight," Kraus said. "That's a mistake."

Experiments started with 20 adult volunteers, who watched and listened to a movie of their choice. "'Men in Black,' 'The Incredibles,' 'Best in Show' were favorites," Kraus said.

As they watched movies, the volunteers also listened to Mandarin words that sounded like "mi" continuously at conversation level in the background. Mandarin is a tone language, where a single word can differ in meaning depending on its tone. For example, the Mandarin word "mi" means "to squint" when delivered in a level tone, "to bewilder" when spoken in a rising tone, and "rice" when given in a falling then rising tone.

The researchers recorded neural responses from the brains of volunteers during the experiments. Half the volunteers had at least six years of training in a musical instrument starting before the age of 12. The others had no more than three years of musical experience. All were native English speakers who had no knowledge of Mandarin.

"Even with their attention focused on the movie and though the sounds had no linguistic or musical meaning for them, we found our musically trained subjects were far better at tracking the three different tones than the non-musicians," said neuroscientist Patrick Wong at Northwestern University.

Wong emphasized these results were seen "in more or less everyday people. You don't have to be a top musician to find these kinds of effects."

Surprisingly, the researchers found these changes occurred in the brainstem, the ancient part of the brain responsible for controlling automatic, critical body functions such as breathing and heartbeat.

Music was thought largely to be the province of the cerebral cortex, where higher brain functions such as reasoning, thought and language are seated. The brainstem was thought to be unchangeable and uninvolved in the complex processes linked with music.

"These results show us how malleable to experience the brainstem actually is," Kraus said of the findings detailed in the April issue of the journal Nature Neuroscience. "We think music engages higher level functions in the cortex that actually tune the brainstem."

Much remains open for investigation. "How much musical training would you need for this to be helpful?" Kraus wondered. "Would music help children with literacy problems? How old would you have to be to see these effects?"