Auditory GABA levels and FC between Heschl's gyrus and ACC mediate the relationship between hearing loss and cognitive impairment in presbycusis

Motivation: The increasing evidence suggests a connection between presbycusis and cognitive impairment, yet the neurochemical mechanisms remain largely unexplored. Goal(s): To compare auditory cortex metabolite levels and brain functional connectivity strength between presbycusis patients and healthy controls, and explore their potential associations with cognitive function and hearing. Approach: We used Magnetic Resonance Spectroscopy (MRS) and resting-state functional Magnetic Resonance Imaging (rs-fMRI). Results: We found reduced GABA levels in the auditory cortex (AC), and decreased connectivity between the AC and the ACC in presbycusis. Furthermore, the changes jointly mediated the association between hearing loss and declines in verbal memory and information processing speed. Impact: These findings support the sensory deprivation hypothesis and highlight the role of GABA-induced inhibitory reduction and the dysconnectivity of AC and ACC in presbycusis-related cognitive impairment, providing new insights into the neurochemical mechanisms of hearing loss-associated cognitive impairment.