As musicians age, musical training may help them to preserve their listening perception by sharpening brain activity patterns linked with speech and audiovisual processing, according to a new study.
Aging has been associated with a multitude of cognitive declines that can lead to impairments in perception, memory and thinking as the brain ages along with the rest of the body. Prior research suggests that these declines may not be as common in older adults who play musical instruments – but it has been unclear exactly how musical training could help aging musicians to preserve cognitive abilities such as speech perception and multisensory processing.
The study, published in the April 28 issue of Science Advances, highlights potential neural mechanisms that could help to explain mounting evidence that suggests short- and long-term musical training in older adults may improve speech-in-noise perception – the ability to discern speech over background noise.
During audiovisual speech-in-noise perception tasks, older musicians around 65 years old outperformed older non-musicians of the same age and performed similarly to younger non-musicians. Functional magnetic resonance imaging (fMRI) scans indicated that older musicians preserved neural function in sensorimotor brain regions and enhanced activity in overlapping regions involved with auditory, visual and motor processing.
The findings add depth to existing evidence that suggests musical training could help to improve neuroplasticity, even in older adults. Two co-authors of the current study, Lei Zhang and Yi Du from the Key Laboratory of Behavioral Science and the department of psychology at the Chinese Academy of Sciences in Beijing, previously reported that musical training could improve aging musicians’ auditory working memory – the ability to remember and use information about sounds heard in the past. But so far, it has been unclear how different brain regions may interact to improve these faculties.
The advantages could be linked to both the preservation of youth-like function and the enhancement of compensatory scaffolding, the researchers hypothesized. Compensatory scaffolding is the aging brain’s way of harnessing large-scale brain networks and other brain regions – such as the frontal motor cortex – to compensate for declines in cognitive function. “Greater recruitment of frontal areas might represent a compensatory scaffolding for greater listening effort, cognitive control and sensorimotor integration,” Lei Zhang and colleagues wrote in the new study.
Youth-Like Neural Activity in Older Musicians
For the experiment, Zhang and colleagues recruited 25 older musicians near 65 years old, 25 older non-musicians of similar ages, and 24 younger non-musicians around the age of 23. As their brains were scanned using fMRI, the participants were shown videos of lip movements voicing different variations of four syllables – ba, da, pa and ta – and tasked to identify the syllables over three different levels of noise representing a spectrum of sentences uttered by 50 Chinese-speaking women.
For all but the noisiest of signals, older musicians performed on par with younger non-musicians in their ability to identify syllables within background noise. They outperformed older non-musicians at all noise levels.
“We expect that vocalists may have better speech-in-noise perception, since the brain regions engaged in singing and speaking are highly overlapped,” the authors wrote. “Percussionists may also perform better in continuous audiovisual speech-in-noise perception because of their superior rhythm skills.”
Shared Brain Networks Working in Concert
Prior studies have suggested that musical training at any age may improve speech perception by consistently “exercising” shared brain regions responsible for both speech and music processing, such as the inferior frontal gyrus and ventral precentral gyrus. Less is known about how musical training could sharpen larger-scale networks. By adding visual cues to speech-in-noise perception tasks, the researchers sought to clarify how auditory, visual and motor regions may interact in the brains of aging musicians.
“In older musicians, the shared brain networks for speech and music processing may provide a [means] by which musicianship generates the cross-domain transfer benefit in processing audiovisual speech in noise,” they wrote.
These findings indicate that musical training not only preserves youthful sensorimotor functioning but may also make older musicians’ brains more adaptable to recruiting frontal-parietal brain regions and deactivating “default mode networks” in the brain’s angular gyrus. Disruptions to the brain’s default mode network – a large-scale system of brain connections thought to engage or disengage as needed for certain tasks – have previously been associated with Alzheimer’s disease.
The researchers surmise that neural preservation and compensation mechanisms work in concert to sharpen speech perception in older musicians, supporting theories that musical training can enhance multisensory functioning and support neuroplasticity in the aging brain.
“Our findings provide insights into adaptive brain reorganization in the aging populations and how lifelong musical training experience leads to ‘successful aging’,” the researchers wrote. “The functional preservation of sensorimotor regions, along with compensatory [default mode network] deactivation also suggests avenues for more targeted training regimens to protect speech functions in the elderly.”