Sensitivity of individual and composite test scores from the Cogstate Brief Battery to mild cognitive impairment and dementia due to Alzheimer’s disease

Abstract

AbstractBackgroundThe Cogstate Brief Battery (CBB) is a computerized cognitive test battery found to detect and confirm cognitive deficits related to Alzheimer’s Disease (AD). As the clinical AD and normative samples used to understand the sensitivity of the CBB to AD have been relatively small and varied in terms of selection criteria, it is important to examine the ability of all CBB measures, and potential composites, to discriminate adults with mild cognitive impairment (MCI) and dementia due to AD from carefully selected cognitively unimpaired (CU) adults.MethodAll speed and accuracy measures from the CBB were examined and both theoretically and statistically derived composites were created, from a sample of 4969 CU adults and 185 adults who met clinical criteria for MCI (clinical dementia rating, CDR = 0.5) or dementia (CDR > 0.5) due to AD.ResultIndividual CBB measures of learning and working memory showed high discriminability for AD‐related cognitive impairment for CDR 0.5 (AUCs ∼ 82‐.85), and CDR > 0.5 (AUCs ∼ .90‐.95). There was also high discrimination ability for theoretically derived CBB composite measures, particularly for the Learning and Working Memory (LWM) composite measure (CDR 0.5 AUC = .83, CDR > 0.5 AUC = .97). Various statistically derived linear composite measures showed discrimination abilities similar to the LWM composite.ConclusionIn older adults, the CBB is an effective instrument for objectively discriminating cognitive impairment due to MCI or AD‐dementia from unimpaired cognition, with the LWM composite being a near‐optimal linear CBB composite for that purpose.