"Could you repeat that?" The reason you may have to say something twice when talking to older family members at Thanksgiving dinner may not be because of their hearing. Researchers at the University of Maryland have determined that something is going on in the brains of typical older adults that causes them to struggle to follow speech amidst background noise, even when their hearing would be considered normal on a clinical assessment.
In an interdisciplinary study published by the Journal of Neurophysiology, 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 Behavior Initiative.
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Why is this the case? "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," Presacco said. "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."
In short, they think signal processing is to blame, not signal transmission.
(Score: 2) by AthanasiusKircher on Thursday October 20 2016, @03:23AM
Unfortunately most of the research I'm familiar with is secondhand through audiophiles and mix engineers, and as you can't even get consensus with sample rates and bit depth, it's going to remain in the realm of scientific woo for a while.
There's a subdiscipline called "auditory scene analysis" that deals specifically with this stuff, and they've been running experiments for at least 25-30 years trying to nail it down. Yes, computationally, it's really hard to model, and it's really hard to get computers to break down stuff the way humans do. But we actually know a LOT about human abilities to deal with this stuff -- there's plenty of research in journals on psychoacoustics and sound cognition about it.