Association Between Age-Related Sensory and Metabolic Hearing Loss and Cognitive Performance.

The underlying mechanisms linking age-related hearing loss (HL), and cognitive dysfunction are not well-understood. Traditionally, age-related HL was primarily related to damage of hair cells (i.e., the sensory component of HL) however, growing evidence suggests that the endocochlear potential (i.e., the metabolic component of HL) may also play a role. In this study, we investigated the relationship between the sensory and metabolic components of HL and cognitive dysfunction in 100 older adults. Forty participants were patients with mild cognitive impairment recruited during visits to the Memory Clinic at the Danish Dementia Research Centre, while 60 participants were recruited from the general public. All participants were assessed with pure-tone audiometry and a comprehensive cognitive test battery including but not limited to tests examining, episodic memory, processing speed, and executive functions. The sensory and metabolic components of the HL were estimated based on the age-related HL components model. Metabolic HL was strongly correlated with performance on tests of processing speed, moderately correlated with performances on tests of executive function, but not significantly correlated with episodic memory performance. On the other hand, sensory HL was not significantly correlated with any of the cognitive tests. When correcting for age, the correlation between metabolic HL and processing speed remained significant. Thus, participants with lower processing speed were significantly more likely to have a larger metabolic HL. These data could lend support to the idea that shared vascular pathophysiological mechanisms are a key link between age-related HL and cognitive decline.