Multiple Sensory Impairments in Relation to Cognitive Function: Two Nationwide Cross-sectional Studies

Abstract

Introduction: Sensory impairments (SIs, including visual, hearing, olfactory, and taste impairments) have been individually associated with age-related cognitive function. Little is known regarding their combined associations with cognitive function.

Methods: We included 2,931 participants (mean age of 69.1 years) from the National Health and Nutrition Examination Survey (NHANES, 2011-2014) and 10,785 participants (mean age of 70.2 years) from the National Health Interview Survey (NHIS, 2021). Status of visual, hearing, olfactory, and taste functions were self-reported in structured questionnaires. In NHANES, cognitive function was objectively measured by a battery of tests, including memory, verbal fluency, and processing speed. NHIS participants answered a single question about subjective cognitive complaints (SCC). We used regression models to assess the relation of the total number and the individual sensory impairments to z-scores of cognitive domains (linear regression) in NHANES and to SCC (logistic regression) in NHIS.

Results: A larger number of SI was related to poorer domain-specific cognitive function (all Ptrend <0.05), including memory (beta _{each additional SI} = -0.12, 95% confidence interval: -0.17 to -0.08), verbal fluency (-0.05, -0.10 to -0.01), and processing speed (-0.13, -0.16 to -0.09). In NHIS, each additional SI was related to 96% higher odds of SCC. We also observed independent associations of sensory impairments (except olfactory impairment) with specific cognitive domains. In addition, each individual SI was associated with higher odds of SCC (the odds ratios ranged from 1.30 to 1.78).

Conclusion: A larger number of SI was related to worse cognitive function and higher odds of SCC.

Keywords: Sensory impairment; brain aging; cognitive function; cross-sectional study; hearing impairment; olfactory impairment; taste impairment; visual impairment.