Abstract
Hearing loss and cognitive impairment frequently co-occur, but the mechanisms linking them are as yet unclear. Their relationship may be causal: Because of sensory deprivation due to hearing loss, cognition may decline. Alternatively, their relationship may be due to a common cause: Both hearing and cognitive impairments may be signs of overall neurological losses. To explore these possibilities, we examine the potential mediating role of social engagement. People with hearing loss may experience restricted social engagement; and in turn, social isolation has been shown to be associated with cognitive decline. We use multilevel models to test this mediation hypothesis in a sample of 5,074 participants in the Wisconsin Longitudinal Study, a survey of white high school graduates whose hearing and cognition were followed between the ages of 65 and 72. We find that hearing loss and infrequent in-person social engagement with friends and relatives are independently associated with poorer memory performance at age 65. However, frequency of social engagement does not explain the association between hearing and memory. Moreover, neither hearing loss nor social engagement is associated with memory decline over 7 years. We further investigate additional measures of sensory impairment (e.g., vision loss), measures of the quality of social engagement (e.g., emotional support), and measures of other domains of cognition (e.g., executive function). Results suggest a common cause, whereby sensory and cognitive impairment are both signs of general neurological decline. We discuss implications for detection and diagnosis of impairment, as well as for interventions to boost social engagement.