Think of the brain like a bustling city, with its own intricate network of roads and highways. In a study on presbycusis, a type of age-related hearing loss, scientists used resting-state functional magnetic resonance imaging (rs-fMRI) to explore how this condition affects the brain’s communication network. They discovered that in patients with presbycusis and cognitive decline, the brain’s functional network undergoes a topological reorganization. It’s as if certain roads become more heavily traveled while others experience less traffic. These changes may be the brain’s way of compensating for cognitive impairment, mobilizing additional neural resources to maintain function. By analyzing various metrics like clustering coefficient and characteristic path length, the researchers identified group differences between healthy controls and presbycusis patients. Furthermore, specific nodes in different brain regions showed abnormal connectivity patterns. This is similar to certain neighborhoods experiencing increased or decreased connectivity with other parts of the city. The study also revealed changes in modular connections within the frontal lobe module and prefrontal subcortical lobe module. The brain’s rich-club organization, which refers to highly connected nodes, was also found to be reorganized in presbycusis patients. To delve further into these fascinating findings and gain a deeper understanding of how the brain adapts to hearing loss and cognitive decline, read the full article!

PurposePresbycusis is characterized by bilateral sensorineural hearing loss at high frequencies and is often accompanied by cognitive decline. This study aimed to identify the topological reorganization of brain functional network in presbycusis with/without cognitive decline by using graph theory analysis approaches based on resting-state functional magnetic resonance imaging (rs-fMRI).MethodsResting-state fMRI scans were obtained from 30 presbycusis patients with cognitive decline, 30 presbycusis patients without cognitive decline, and 50 age-, sex-, and education-matched healthy controls. Graph theory was applied to analyze the topological properties of brain functional networks including global and nodal metrics, modularity, and rich-club organization.ResultsAt the global level, the brain functional networks of all participants were found to possess small-world properties. Also, significant group differences in global network metrics were observed among the three groups such as clustering coefficient, characteristic path length, normalized characteristic path length, and small-worldness. At the nodal level, several nodes with abnormal betweenness centrality, degree centrality, nodal efficiency, and nodal local efficiency were detected in presbycusis patients with/without cognitive decline. Changes in intra-modular connections in frontal lobe module and inter-modular connections in prefrontal subcortical lobe module were found in presbycusis patients exposed to modularity analysis. Rich-club nodes were reorganized in presbycusis patients, while the connections among them had no significant group differences.ConclusionPresbycusis patients exhibited topological reorganization of the whole-brain functional network, and presbycusis patients with cognitive decline showed more obvious changes in these topological properties than those without cognitive decline. Abnormal changes of these properties in presbycusis patients may compensate for cognitive impairment by mobilizing additional neural resources.

Read Full Article (External Site)