By exploring differences in the way younger and older adults respond to sounds, neuroscientists at Western University in Canada have found that our brains become more sensitive to sounds as we age. This may lead to hearing challenges over a lifetime.
The researchers examined the auditory cortex responses of participants in their 20s and 60s. They found that younger and older people respond differently to soft and loud sounds.
“We looked at younger and older individuals who have clinically normal hearing and we looked at how the brain’s ability to adjust its sensitivity to sound levels is affected by aging,” said postdoctoral scholar Björn Herrmann, the study’s lead writer. “What we observed is that older individuals don’t adapt as well to their sound environment.”
Older people more over-sensitive to sounds
The study revealed that when young adults are in a loud environment – such as a rock concert – their brains become less sensitive to relatively quiet sounds. This allows the listener to hear the relevant sounds (like a guitar riff) better without being distracted by irrelevant sounds.
However, as a person ages, researchers found that older listeners become over-sensitive to sounds, hearing both quiet and loud sounds without the ability to ignore or tune out irrelevant auditory information. Without the ability to reduce sensitivity to irrelevant sounds, the individual experiences hearing challenges.
“When the sound environment is loud, the brain activity in younger adults loses sensitivity to really quiet sounds because they’re not that important,” Herrmann said. “Whereas older individuals still stay sensitive to these relatively quiet sounds, even though they’re not important at the time.”
Unpleasant and annoying sounds
The study suggests that this over-sensitivity to sounds is one reason why older adults may find certain situations, like a loud restaurant, unpleasantly distracting. It may also explain why they may find some sounds more annoying.
“It’s a fundamental property of the auditory system to be able to adjust really fast to any environment a person goes into. If you cannot do that anymore, then in each situation your auditory system might be a little off. This means older individuals may be easily distracted and overwhelmed by sounds, or find them too loud,” Herrmann explained.
The study was published in Journal of Neuroscience.