Washington: Do you ask people to repeat their words during conversation? Researchers at the University of Maryland have determined that something is going on in the brains of typical older adults that cause them to struggle to follow speech amidst background noise, even when their hearing would be considered normal on a clinical assessment, reports ANI.
In an interdisciplinary study, researchers Samira Anderson, Jonathan Z. Simon, and Alessandro Presacco found that adults aged 61-73 with normal hearing scored significantly worse on speech understanding in noisy environments than adults aged 18-30 with normal hearing. The researchers are all associated with the UMD’s Brain and Behaviour Initiative.
“Evidence of degraded representation of speech in noise, in the aging midbrain and cortex” is part of ongoing research into the so-called cocktail party problem, or the brain’s ability to focus on and process a particular stream of speech in the middle of a noisy environment.
The study subjects underwent two different kinds of scans to measure their brains’ electrical activity while they listened to people talk. The researchers were able to see what the subjects’ brains were up to when asked what someone was saying, both in a quiet environment and amidst a level of noise. The researchers studied two areas of the brain.
In the younger subject group, the midbrain generated a signal that matched its task in each case, looking like speech in the quiet environment, and speech clearly discernable against a noisy background in the noise environment.
But in the older subject group, the quality of the response to the speech signal was degraded even when in the quiet environment, and the response was even worse in the noisy environment. “For older listeners, even when there isn’t any noise, the brain is already having trouble processing the speech,” said researcher Simon.
Neural signals recorded from cortex showed that younger adults could process speech well in a relatively short amount of time. But the auditory cortex of older test subjects took longer to represent the same amount of information.
“This imbalance could impair the brain’s ability to correctly process auditory stimuli and could be the main cause of the abnormally high cortical response observed in our study.” “Older people need more time to figure out what a speaker is saying,” Simon noted.
Simple courtesies can help, too. Since being able to see as well as hear someone speaking helps with speech processing, it’s a good idea to look directly at older adults and make sure you have their attention before talking with them.
“The main message is that the older adults in our study have normal hearing as measured on an audiogram, yet they have difficulty understanding speech in noise because the timing aspects of the speech signal are not being accurately encoded,” said Anderson.