Executive functioning and risk for Alzheimer's disease in the cognitively intact: Family history predicts Wisconsin Card Sorting Test performance.

Abstract

Alzheimer's disease (AD) research typically focuses on memory. However, executive functioning (EF) deficits are also common among AD patients; these deficits are associated with decreased functioning in activities of daily living, an important criterion in diagnosing AD. A classic test of EF ability, the Wisconsin Card Sort Test (WCST), has demonstrated sensitivity to differentiating individuals with AD from healthy controls, discriminating AD groups based on disease severity, and distinguishing AD from other types of dementia. Such sensitivity to AD raises the possibility that the WCST is also sensitive to very early, preclinical differences between those who have heightened risk for AD and those with lower risks. The current study, therefore, examined WCST performance in healthy, cognitively intact older adults with a first-degree (i.e., sibling or parent) family history (FH) of AD (n = 18) and those with no such FH of AD (n = 24). Results revealed significant group differences for Categories Achieved, Percent Conceptual Level Responses, Total Errors, Perseverative Errors, and Non-Perseverative Errors, with the FH+ group consistently exhibiting poorer performance. Moreover, hierarchical regression analyses indicated that after accounting for age, sex, and education, FH significantly predicted all 5 of these variables. These results speak to the potential role of EF in bolstering the current understanding of early cognitive markers of future decline. Furthering what is known about the relationship between AD and nonmemory specific domains of cognition such as executive functioning may allow for better prediction of cognitive decline and potential progression to AD.