Holding a conversation in a mall this holiday-time may prove difficult with the increasingly loud crowds, particularly for the elderly. But the musicians in the group may have an advantage, according to a new study. Having musical training appears to help older adults separate distinct sounds, the researchers found.
The new study built on past work that showed neural changes in musicians but went a step further to see how musical training influences age-related changes in auditory processes. For scientist Claude Alain, the youngest of 12 children and with 20 aunts and uncles, understanding these aging processes was personal. “I noticed older family members having difficulty following conversations in our large family get-togethers,” says Alain, who studies sound processing at the Rotman Research Institute, Baycrest Centre in Toronto. Himself a guitar player, Alain set out with doctoral student and fellow amateur musician Benjamin Zendel to take a closer look at the connection between musical training, listening skills, and aging.
They recorded event-related potentials (ERPs) to measure how the brain responds to concurrent sounds. They created sounds to “mimic the general principal in which complex sounds occur in our everyday environment,” Alain says, which involves multiple harmonics operating at different frequencies. Think of how a note played on a piano sounds different from the same note played on a violin, despite having the same pitch, explains Zendel, who is now a postdoctoral fellow in the International Laboratory for Brain, Music and Sound Research at the University of Montreal. These differences are explained by harmonics. “The brain ‘groups’ these harmonics into a single tone,” Zendel says. “In the lab, we can exploit this to understand how the brain uses frequency information to group and segregate sounds that occur simultaneously.”
In their experiment reported in the Journal of Cognitive Neuroscience, older (age 58-91) musicians, older nonmusicians, younger (age 22-33) musicians, and younger nonmusicians all listened to computer generated buzzes made up of multiple harmonics. When the frequencies of all the harmonics were mathematically related, like the harmonics produced by a single piano note, participants heard a single buzz-like sound. When one of the harmonics was mistuned from its original value, participants heard the mistuned harmonic as a distinct sound similar to a tuning fork, in addition to the buzz-like sound.
They found that musicians, both older and younger, were more likely to hear two distinct sounds when the second harmonic was mistuned by 2% or more. In all participants, researchers observed a brain wave called an object-related negativity (ORN) in association with the perception of two distinct sounds. Importantly, the ORN was present even when a listener was focused on a different task. “In a sense, the ORN is like a reflex to the presence of concurrent sounds,” Zendel says. And, adds Alain, it provides a way to investigate concurrent sounds even in individuals who have difficulties understanding task instructions, such as young children or patients with dementia.
The brains of the younger musicians automatically detected the presence of the mistuned harmonic better than any other group, with the ORN the largest and occurring the earliest compared to the other groups. The older musicians relied on a second, non-reflexive neural process to detect the second sound at the same level as the younger musicians. Importantly, this process hinged on the participant paying attention to the auditory environment. “We think of it as that musical training does not affect hearing in the ear level but rather how older individuals listen to sounds in the brain,” Alain says, making them better listeners.
The take-home message, the researchers say, is that musical training can make you a better listener not only for musical sounds but also for other types of sounds or in situations like a cocktail party. Therefore, Zendel says, lifelong musicianship has significant benefits for older adults. “Given that age-related hearing difficulties are nearly universal, music playing may be a simple, non-invasive method to maintain listening skills into old age.”
Both Alain and Zendel are eager to continue this research by looking at other aspects of lifelong musicianship – for example, how much musical training is necessary to see advantages later in life. “Once we understand how musicianship influences myriad auditory processing tasks, we may be able to use aspects of musical training as a form of auditory rehabilitation,” Zendel says.
-Lisa M.P. Munoz
“The Influence of Lifelong Musicianship on Neurophysiological Measures of Concurrent Sound Segregation,” Benjamin Rich Zendeland Claude Alain, Journal of Cognitive Neuroscience, online Nov. 19, 2012.
Media contact: Lisa M.P. Munoz, CNS Public Information Officer, firstname.lastname@example.org