In a new study, researchers found older people’s hearing problems may be because their brains work with less information.
They found that the neural response of the midbrain of older listeners is not merely less well synchronized than for younger listeners, but also actually contains less information.
The research was conducted by a team from the University of Maryland.
Younger adults with normal hearing can typically understand speech in the presence of a competing speaker without much effort, but this ability to understand speech in challenging conditions deteriorates with age.
Older people, even with normal hearing, often have problems understanding speech in noise.
Previous studies have shown that the frequency-following response (FFR) generated by the midbrain indicates age-related neural deficits.
In the current study, the team examined the amount of stimulus information contained in the FFR.
They found a broad-band informational loss linked to aging for both FFR amplitude and phase.
This age-related loss of information is more severe in higher frequency FFR bands.
The team also found that older adults benefit neurally, i.e., show a reduction in loss of information, when the speech is changed from meaningful (talker speaking a language that they can comprehend, such as English) to meaningless (talker speaking a language that they cannot comprehend, such as Dutch).
The findings suggest that age-related informational loss may be more severe when the speech is meaningful than when it is meaningless.
The team believes their findings may help develop new methods for improving hearing ability in older people.
One author of the study is Jonathan Z Simon.
The study is published in the Journal of Neurophysiology.
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