Summary: Researchers have identified a measurable neurobiological link between age-related hearing loss (presbycusis) and cognitive decline. The new marker, called the Functional-Structural Ratio (FSR), quantifies how well specific brain regions that process sound, speech, memory, and decision-making remain integrated into the brain’s functional networks. The study shows that as hearing worsens, certain brain areas undergo coordinated structural and functional decline, and those changes in the FSR correlate with poorer memory and executive function—suggesting FSR could help predict dementia risk.
Using magnetic resonance imaging and standardized hearing and cognitive tests, the research team led by Ning Li at Tiangong University and Shandong Provincial Hospital compared people with presbycusis to healthy controls. They measured pure-tone audiometry thresholds (PTA), speech recognition thresholds (SRT), cognitive performance, gray matter volume (GMV) and low-frequency functional activity (ALFF). From these data they derived the Functional-Structural Ratio (FSR) as an index of functional-structural coupling in the brain.
The study found that reduced coupling—lower FSR—occurred in regions that link auditory processing with higher cognitive functions. In particular, the putamen and fusiform gyrus (important for sound and speech processing) and the precuneus and medial superior frontal gyrus (important for memory and decision-making) showed both structural atrophy and reduced functional connectivity in people with presbycusis. These neural changes were associated with worse hearing thresholds and weaker performance on tests such as the Montreal Cognitive Assessment (MoCA), Auditory Verbal Learning Test (AVLT), and the Trail Making Test (TMT-A).
Key findings
- FSR as a biomarker: The Functional-Structural Ratio links the severity of hearing loss with the degree of cognitive impairment by measuring how well brain structure and function remain coupled.
- Targeted brain regions: The putamen and fusiform gyrus (auditory and speech processing) and the precuneus and medial superior frontal gyrus (memory and executive function) are especially vulnerable to decoupling in presbycusis.
- Coupled decline: Hearing loss is associated with simultaneous gray matter atrophy and reductions in functional activity in these regions, indicating coordinated structural-functional reorganization.
- Predictive relationships: Lower FSR values correlate with higher PTA and SRT (poorer hearing) and with worse scores on memory and executive function tests, supporting its potential to indicate dementia risk.
- Clinical implication: Preserving hearing health—through protection, assessment, and appropriate intervention—may help protect brain network integrity and reduce risk of cognitive decline.
Why this matters
This work provides the first direct neurobiological evidence that sensory decline and cognitive impairment share a common pattern of brain reorganization. By quantifying functional-structural coupling, the FSR offers a measurable way to track how auditory deficits affect broader neural networks involved in memory and decision-making. Because FSR reductions are associated with both hearing thresholds and cognitive test scores, FSR could be useful for early screening and monitoring of individuals at higher risk for dementia linked to hearing loss.
Key questions answered
A: When the brain receives degraded or fewer sound signals, auditory regions can lose functional connections with other networks. Because these auditory regions also contribute to memory and decision-making circuits, that disconnection can spread and impair broader cognitive function.
A: FSR compares measures of functional brain activity (ALFF) with structural measures (GMV) to assess whether physical brain tissue and its activity remain in balance. A lower FSR indicates reduced coupling between structure and function, reflecting neural reorganization associated with hearing loss and cognitive decline.
A: This study does not test interventions directly, but the authors note that preserving hearing health may protect brain integrity. Maintaining auditory input—through hearing protection, assessment, and use of aids where appropriate—could help sustain neural networks and potentially reduce cognitive decline risk.
Study methods and significance
The investigators assessed hearing thresholds, speech recognition, and multiple cognitive domains in people with presbycusis and matched healthy controls. Brain MRI measures included gray matter volume (GMV) and amplitude of low-frequency fluctuations (ALFF), which index spontaneous functional activity. The researchers computed FSR from ALFF and GMV to quantify functional-structural coupling. They observed significant correlations between GMV atrophy and ALFF changes in the putamen, fusiform gyrus, precuneus, and medial superior frontal gyrus. These neural changes aligned with worsening PTA and SRT and with declines on cognitive tests, supporting the view that presbycusis involves coupled structural and functional brain decline.
Implications for clinicians and patients
For clinicians, FSR provides a promising imaging marker that could help identify patients whose hearing loss puts them at greater risk for cognitive decline. For patients and caregivers, the findings reinforce the importance of monitoring and addressing hearing problems early. Preserving auditory input and engaging in hearing health care may help maintain brain network integrity during aging.
Editorial notes
- Edited by a Neuroscience News editor.
- Journal paper reviewed in full by the editorial team.
- Contextual summary added by staff to clarify clinical relevance.
About this research
Author: SfN Media
Source: SfN
Contact: SfN Media
Image: The image is credited to Neuroscience News
Original Research: Functional–Structural Coupling: Brain Reorganization in Presbycusis is Related to Cognitive Impairment. Xiaojie Li, Weilong Fu, Yao Wang, Yuting Gao, Jinhai Wang, Jing Yang, Longji Xu, Fei Gao, Xiao Li and Ning Li. eNeuro. DOI:10.1523/ENEURO.0294-25.2026. (Closed access)
Conclusion
This study introduces the Functional-Structural Ratio (FSR) as a clear neurobiological link between age-related hearing loss and cognitive decline. By demonstrating coordinated structural and functional brain changes in auditory and cognitive regions and showing that those changes relate to both hearing thresholds and cognitive test performance, the work highlights hearing preservation as a potentially important strategy for protecting brain health as people age.