Research has been piling up over the past decade that shows training can boost everything from pitch perception to visual and motor skills.

And now a new study says it may also improve language-processing abilities—a finding that lends support to the effectiveness of teaching letters and words to kids through songs, as TV programs like Sesame Street have done for years.

Researchers report in Proceedings of the National Academy of Sciences USA that music triggers changes in the brain stem—as well as in the cortex or outer brain layers as previously reported. Senior study author Nina Kraus, a professor of neurobiology and physiology at Northwestern University, says this means music training may not only improve a person's ability to decipher different tones but also enhances reading and speech functions, because the brain stem is a pathway for both music and language. If that is the case, music instruction may be used as a tool to help children with speech difficulties and learning deficits.

Scientists previously believed that the strength of neuron connections in the brainstem was fixed, but the new findings suggest otherwise. "What we are showing here is the very basic circuitry of the brain is in fact more malleable than we previously thought," Kraus says. "What you do with your senses actually shapes what the circuitry becomes; [it] tunes your sensory apparatus."

"I think of music as being kind of quintessential multisensory activity," she adds, owing to elements of performance, as musicians follow cues from others and must read, feel and hear concurrently.

Kraus's team conducted experiments on 29 subjects averaging 25 years of age, 16 of whom had been playing instruments from the age of five. The subjects donned scalp electrodes localized to each's brain stem region to measure the activity of neurons there while they were exposed to different stimuli. In one case, the participants viewed someone saying syllables of speech, such as the sound "da" or they watched someone bow a cello. In the second construct, the subjects heard the sounds from the previous films while they watched an unrelated, silent movie designed only to keep their attention.

"When you measure these electrical responses, they are exquisitely sensitive to timing," Kraus says. "In speech, the sound wave changes in fractions of milliseconds [corresponding to different syllables]. … When we look at these brain waves, we can see changes mirrored."

The researchers discovered that for both conditions (auditory alone and paired audio-visual), the musicians had sharper and more enhanced encoding of important cues related to pitch and tone. There was not only more activity in the musicians' brain stems, but that brain region also responded more quickly to the stimuli. The longer a person had been practicing an instrument, the sharper his or her responses were. Originally, the researchers expected the musicians to have a leg up only on the cello exercise, but it turned out they were more responsive to the speech sounds as well.

Jonathan Burdette, an associate professor of neuroradiology at Wake Forest University Medical Center, who has studied the cortical effects of music training on orchestral conductors, notes that anecdotally, many of the smarter children in school are students who play music. "There's been a gap between anecdotal observations and the science behind [the phenomenon]," he says. "This article is helping fill that gap" by further elucidating the mechanistic changes music instruction can bring about in the brain.

According to Kraus, 30 to 40 percent of children who have learning and reading problems do not transcribe sound well. She says her lab is interested in researching ways that musical training may be able to improve auditory function by erasing those deficits. "We want to really study systematically the extent to which musical training can help speech-related auditory processing," she says.

"The people that came up with Sesame Street and The Electric Company—they were brilliant," Kraus says, about the two children's programs that pair music and phonics. "Our work would support the ideas behind that kind of approach."