Abstract
INTRODUCTION: Many studies have established the relationship between greater burden of beta-amyloid (aβ), a marker of Alzheimer's disease (AD), and poorer neuropsychological performance. However, it is poorly understood whether neuropsychological test scores predict aβ deposition. This study aimed to evaluate the predictive utility of neuropsychological test scores on aβ deposition in a sample of older adults across the late-life cognitive spectrum. METHOD: One hundred and sixty-five older adults classified as cognitively intact (n = 68), single- or multi-domain amnestic mild cognitive impairment (MCI; n = 52) or mild dementia (n = 45) completed amyloid positron emission topography (PET), and neuropsychological measures including Hopkins Verbal Learning Test - Revised (HVLT-R), Brief Visual Memory Test - Revised (BVMT-R), Trail Making Test (TMT) Parts A and B, and Symbol Digit Modalities Test (SDMT). A series of hierarchical regression were evaluated to assess the predictive association of cognitive test scores to aβ deposition. RESULTS: In a predominantly non-Hispanic White, college-educated sample, HVLT-R Total and Delayed Recall were negatively associated with aβ deposition above and beyond demographic covariates (i.e. age, sex, years of education, estimated premorbid functioning), accounting for 31% and 39% of variance in aβ, respectively (p < .001). Similarly, BVMT-R Total and Delayed Recall scores each accounted for 31% of variance (p < .001). Effect sizes for processing speed and executive functioning scores were smaller, with SDMT explaining 12% of the variance and TMT-A and TMT-B explaining 7% and 9% of the variance, respectively (p < .001). CONCLUSION: Cognitive test scores significantly predicted aβ deposition, with memory measures in particular accounting for approximately a third of the variance. These results provide a proof of concept for use of neuropsychological test scores as tools for estimating biomarkers in neurodegenerative disease.