Clinical Utility of Select Neuropsychological Assessment Battery Tests in Predicting Functional Abilities in Dementia

Abstract

Objective: Neuropsychological test performance can provide insight into functional abilities in patients with dementia, particularly in the absence of an informant. The relationship between neuropsychological measures and instrumental activities of daily living (IADLs) is unclear due to hetereogeneity in cognitive domains assessed and neuropsychological tests administered. Practical and ecologically valid performance-based measures of IADLs are also limited. The Neuropsychological Assessment Battery (NAB) is uniquely positioned to provide a dual-purpose assessment of cognitive and IADL function, as it includes Daily Living tests that simulate real-world functional tasks. We examined the utility of select NAB tests in predicting informant-reported IADLs in mild cognitive impairment and dementia.

Methods: The sample of 327 participants included 128 normal controls, 97 individuals with mild cognitive impairment, and 102 individuals with Alzheimer's disease dementia from the Boston University Alzheimer's Disease Center research registry. Informants completed the Lawton Brody Instrumental Activities of Daily Living Scale, and study participants were administered selected NAB tests that were complementary to the existing protocol.

Results: ROC curves showed strongest prediction of IADL (AUC > 0.90) for memory measures (List Learning delayed recall and Daily Living Memory delayed recall) and Daily Living Driving Scenes. At a predetermined level of specificity (95%), List Learning delayed recall (71%) and Daily Living Memory delayed recall (88%) were the most sensitive. The Daily Living Memory and Driving Scenes tests strongly predicted IADL status, and the other Daily Living tests contributed unique variance.

Conclusions: NAB memory measures and Daily Living Tests may have clinical utility in detecting informant-rated functional impairment in dementia.