Polygenic risk for hearing abilities and longitudinal cognitive outcomes in older adults

Abstract

Hearing loss (HL) is a major modifiable risk factor for cognitive decline and dementia, particularly Alzheimer's disease (AD). However, the relationship between hearing loss and cognitive decline as influenced by common biological factors, i.e. genetic predisposition, is not fully understood. Furthermore, auditory behavioral tests may be potential biomarkers of cognitive decline. This retrospective study examined whether hearing abilities were associated with cognition among older adults, after controlling for genetic predisposition for HL and AD. In a longitudinal cohort of 3,232 older adults ( M = 78.0 ± 8 years; mean cognitive follow-up, 6.9 years) cognition was assessed annually across five domains. Self-reported hearing loss was assessed using questions about hearing in a quiet environment and difficulty understanding speech on the phone. In a subset of the participants ( n = 113; M = 76.0 ± 6 years, mean cognitive follow-up, 8.6 years), hearing abilities were also measured at a single time point, using four different hearing assessments, including tasks assessing central auditory processing abilities. Linear mixed effects modeling results showed that self-reported hearing ability was not associated with cognitive level or rate of cognitive change during follow-up. In the measured-hearing subset, global hearing ability was associated with cognitive level at the analytic baseline, but not with subsequent cognitive change. Specifically, two tests of complex spectral pattern discrimination were significantly associated with global cognition at the analytic baseline, but not with the rate of subsequent cognitive change. In contrast, pure-tone audiometry and speech-in-noise ability were not associated with global cognition at the analytic baseline or longitudinally. Current findings support the utility of central auditory processing tests as screening tools for cognitive ability in older adults. However, large-scale auditory and neurophysiological studies are needed to fully assess the feasibility of novel central auditory processing tests and to clarify relationships between genetics, hearing loss and cognitive decline/dementia.