Peripheral and central hearing impairment and their relationship with cognition: a review.

Objective: To consider the relationships between both peripheral and central hearing impairment and cognition. Design: Narrative review. Study sample: Numerous studies exploring the relationship between hearing impairment and cognitive function, particularly in an older population. Results: In addition to the well-documented relationship between peripheral hearing loss and cognition highlighted in previous comprehensive reviews, there is also some evidence to suggest that there is a relationship between central hearing impairment and cognition. Further research is required to better understand this relationship and its effects on hearing aid benefit in people with both peripheral hearing loss and central hearing impairment. Conclusions: To fully understand the relationship between hearing impairment and cognitive impairment, not only peripheral but central hearing needs to be considered. Such knowledge could be of benefit in the clinical management of people with both peripheral hearing loss and central hearing impairment.

The relationship between peripheral hearing loss and higher order listening function on cognition in older Australians.

Objective: Peripheral hearing, central auditory processing (CAP) and cognition are all important for comprehension of speech and deteriorate with increased age. This study aimed to examine the relation between hearing impairment and cognitive impairment by assessing both peripheral hearing impairment and CAP ability.Design: Cognition was measured using the CogState Brief Battery (CSBB). Peripheral hearing was measured across eight frequencies (250 Hz-8000 Hz) using pure tone audiometry, and CAP was measured using the Listening in Spatialised Noise-Sentences test (LiSN-S) and the Dichotic Digits Test. Data were analysed using correlation and regression analyses.Study sample: Around 85 adults aged 60.33-83.08 years who attended the Melbourne Audiology clinic and had no previous diagnosis of dementia were included in the study.Results: A significant association was found between degree of peripheral hearing impairment and the cognitive skills of attention and executive function as measured by the CSBB. Additionally, CAP abilities as assessed using the LiSN-S test were significantly correlated with at least one cognitive measure.Conclusions: This study adds to the knowledge that peripheral hearing and CAP ability both share an association with cognition, specifically identifying cognitive skills and measures of "hearing" that mediate this relationship.