Have you ever wondered why older adults might struggle to understand speech even with good hearing? The answer lies in how their brains process information. Stefan Elmer, Nathalie Giroud, and their team uncovered the reasons behind this phenomenon.
Age-related hearing challenges are not just a matter of our ears. Recent studies by the University of Zurich have shed light on why older individuals may find speech comprehension difficult even with intact hearing or when wearing hearing aids.
Stefan, Nathalie, and their team delved into this phenomenon using a combination of electroencephalography (EEG) and magnetic resonance imaging (MRI), looking at younger and older adults. MRI allows scientists to capture the brain’s physical structure revealing, for example the density of gray matter, while EEG detects abnormalities in the electrical activity of a brain.
One striking discovery was that older individuals perceive speech sounds differently, leading to difficulties distinguishing similar sounds. Further analysis provided insights into how the brain responds to sound. Older adults showed altered electric brain responses to speech, indicating changes in auditory processing. Additionally, structural brain imaging showed underlying age-related variations in gray matter infrastructure. In older adults, the auditory networks show strong thinning with age, suggesting they need to process sounds with fewer neuronal resources than their younger counterparts.
In essence, these studies demonstrate that age-related difficulties in understanding speech aren’t solely attributed to hearing loss but rather how the aging brain interprets and reacts to auditory information.
Stefan Elmer, Ira Kurthen, Martin Meyer & Nathalie Giroud. A multidimensional characterization of the neurocognitive architecture underlying age-related temporal speech processing. NeuroImage (2023)
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