Pure tone auditory thresholds and their association with cognition in the Canadian Longitudinal Study on Aging

Age-related hearing loss (ARHL) is associated with cognitive decline and was identified as the strongest modifiable individual risk factor for dementia. However, inconsistencies in the reported strength of this association have been observed. The present study aimed to assess whether differences in the range of sound frequencies used to determine pure tone average (PTA) thresholds could explain the inconsistencies. Data from 13,654 older adults in the Canadian Longitudinal Study on Aging were used to compute four different PTA thresholds: Low frequency, Speech (corresponding to frequencies used in speech), High frequency, and Average (of all 8 tested frequencies). Two cognitive composite scores were computed for memory and executive function. Correlation and partial correlation analyses, controlling for age, sex, education, cardiovascular risk factors, symptoms of depression and use of hearing aids were conducted, followed by stepwise regression to establish the parameter combination that reflects the strongest hearing-cognition association. PTA was found to be negatively correlated with both cognitive scores for the four methods used to determine PTA and the association remained significant after controlling for covariates. The optimal parameter combination was frequencies 0.5 kHz, 1 kHz and 2 kHz for memory and 0.5 kHz and 3 kHz for executive function, controlling for covariates. These findings confirm a negative association between hearing and cognition. However, this association is weak and the discrepancies in the reported strength of the association cannot be fully explained by measurement of hearing thresholds.