Hearing difficulties in old age are related to brain activity, and not ears, says study
Posted on: 21/Oct/2016 9:34:40 AM
A study published in the Journal of Neurophysiology has said that 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. The study was conducted by researchers from the University of Maryland. The researchers 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.
Speaking about this, the researchers said, 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. For older listeners, even when there isn`t any noise, the brain is already having trouble processing the speech.
Part of the comprehension problems experienced by older adults in both quiet and noise conditions could be linked to age-related imbalance between excitatory and inhibitory neural processes in the brain. 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. They are dedicating more of their resources and exerting more effort than younger adults when they are listening to speech. Often we will hear an older person say, `I can hear you, I just can`t understand you. This research gives us new insight into why that is the case. The older brain just drops part of the speech signal, even if the ears captured it all just fine. When someone can see you speaking, instead of only hearing you, their visual system can sometimes make up for that loss.
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. Because they have normal hearing, talking louder does not help. So if someone is having trouble understanding you in a noisy restaurant or in a crowded room, it is most important to speak clearly at a normal or slightly slower than normal rate. Your older loved ones will appreciate this courtesy during the upcoming holidays.
