Understanding Speech in Noise: New Findings on the Role of the Insula and Aging

Age is a significant factor affecting the auditory system, and the ability to understand speech in noise, in particular, deteriorates markedly with aging and age-related hearing loss. It is known that the process of comprehending spoken language is influenced by changes in cognitive, social, and emotional processes, as well as the interactions between these changes.

Bu görsel, yapay zekâ destekli bir görsel oluşturma aracı kullanılarak hazırlanmıştır.

New research reveals that the age-related decline in speech-in-noise understanding may be linked to the resting-state connectivity and white matter structure of brain regions. This study, conducted by researchers at the University at Buffalo, shows that difficulties in speech perception may be connected to complex communication networks between different areas of the brain. MRI scans taken during a resting state, which showed that the left insula works harder even when sound is not being actively processed, point to a permanent reorganization.

Since structural and functional changes in the insula are also associated with early signs of dementia, these findings may help explain the known link between hearing loss and cognitive decline.

The primary aim of this study, published in the journal Brain and Language, was to examine the relationship between changes in resting-state brain networks and individuals' ability to understand speech in noise. The researchers correlated the speech-in-noise performance of participants aged 22 to 79 with their resting-state functional magnetic resonance imaging (RS-fMRI) and diffusion tensor imaging (DTI) data.

RS-fMRI reveals the connections between different brain regions while an individual is at rest by focusing on spontaneous and intrinsically generated neuronal activity in BOLD (blood-oxygen-level-dependent) signals. DTI provides information about the integrity of white matter tracts, which transmit information in the brain. Fractional anisotropy (FA) is a value measured by DTI that indicates how freely water molecules diffuse in a particular direction within tissue. High FA generally indicates that white matter fibers are intact and organized, while low FA suggests structural degradation or damage. In the study, participants' speech-in-noise scores (QuickSIN) were correlated with RS-fMRI findings and FA values obtained from the auditory section of the corpus callosum, taking the age factor into account. The Ig2 region of the insula showed a significant correlation with the QuickSIN test administered to the right ear when the effect of age was corrected for.

Key Findings:

• Increased activation in the insula: In individuals who have difficulty understanding speech in noise, it was shown that insula connectivity is stronger even during a resting state.

• The link between hearing loss and dementia: It was suggested that the reorganization in the insula could explain the relationship between hearing loss and cognitive decline.

Dr. David S. Wack, an associate professor in the Department of Radiology at the Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo and the study's first author, says the following about his work:

“In individuals with hearing loss, the brain tries to do more processing by recruiting other areas to figure out what's going on. What's interesting is that we observed the insula working harder even when the brain is 'at rest,' meaning there is no conversation or noise present.” “Many studies have established correlations between hearing loss, speech-in-noise understanding, and dementia. Our findings show the changes that occur in resting-state brain connectivity as speech-in-noise performance declines.”

Source: https://neurosciencenews.com/insula-noise-speech-hearing-28829/ 

Wack, D. S., Schweser, F., Wack, A. S., Muldoon, S. F., Slavakis, K., McGranor, C., ... & McNerney, K. (2025). Speech in noise listening correlates identified in resting state and DTI MRI images. Brain and Language, 260, 105503.