Assessing Social Cognition in Older Adults: A Population-Based Study

Abstract

<h3>Introduction</h3> Social cognition is the cognitive domain that processes social information, the means by which we make sense of ourselves in relation to others and our environments. Impaired social cognition is associated with functional dependence on others and can have dire social consequences leading to social isolation, increasing the risk for morbidity and mortality. Social cognition is be impaired in neurodegenerative disorders including Alzheimer's disease (AD). The most recent edition of the American Psychiatric Association's Diagnostic and Statistical Manual for Mental Disorders (DSM-5) include social cognition as one of six core domains of neurocognitive function, alongside memory, executive control, complex attention, language, and visuospatial/perceptuomotor function, that can be impaired in the neurocognitive disorders. We have previously reported population-based norms from older adults on two social cognition measures, the Social Norms Questionnaire [SNQ-22], assessing social perception, and the 10-question version of the Reading the Mind in the Eyes Test [RMET-10], measuring Theory of Mind (ToM). Here, we report on the utility of a social cognition composite measure comprising the SNQ-22 and the RMET-10. <h3>Methods</h3> Participants are 902 adults from a population-based cohort in Pennsylvania. The mean age is 76.6 years (SD 8.06). We created a social cognition composite comprising standardized z-scores on the Social Norms Questionnaire and the 10-item Reading the Mind in the Eyes Test. We described its distribution in the population-based sample of older adults, its association with demographic factors, other cognitive and behavioral measures, the Clinical Dementia Rating (CDR®). We compared sensitivity, specificity, and the area under the curve of social cognition to those of other cognitive domains for mild cognitive impairment (MCI). We calculated the impact of including social cognition as a sixth cognitive domain on the estimated prevalence of (cohort proportion classified as) neuropsychologically defined MCI. <h3>Results</h3> Better social cognition was associated with younger age, female sex, higher education, better general cognition (MMSE), fewer depressive symptoms, and lower Clinical Dementia Rating (CDR). Adjusting for demographics, associations with higher MMSE and fewer depressive symptoms, anxiety symptoms, and subjective cognitive complaints remained significant. The sensitivity and specificity of social cognition for CDR = 0.5 were comparable to those of the traditional five cognitive domains. Including social cognition as the sixth domain of cognition resulted in a 5% increase in the estimated prevalence of MCI. <h3>Conclusions</h3> Better social cognition was associated with younger age, female sex, higher education, better general cognition (MMSE), fewer depressive symptoms, and lower Clinical Dementia Rating (CDR). Adjusting for demographics, associations with higher MMSE and fewer depressive symptoms, anxiety symptoms, and subjective cognitive complaints remained significant. We found that social cognition had sensitivity, specificity for CDR that was comparable to those of the five conventional cognitive domains of attention, executive functions, language, memory, and visuospatial function. The AUC values in the 0.6 – 0.7 range, which were comparable to the reported values in the literature. Considering neuropsychologically defined MCI, the inclusion of social cognition as the sixth domain of cognition resulted in about 5% of the sample becoming newly classified as MCI. These individuals differed from those already classified as MCI only in having higher MMSE scores; but they differed from those still classified as normal in having more anxiety symptoms, lower reading levels, and impairment in the CDR domain of home and hobbies. It appears a worthwhile consideration for standard cognitive assessments in older adults to routinely include brief objective assessments of the social cognition domain. <h3>This research was funded by</h3> The word reported here was supported in part by research grant # R37AG023657 from the National Institute on Aging, National Institutes of Health, US Department of Health and Human Services.