BHA‐CS: A novel cognitive composite for Alzheimer's disease and related disorders

INTRODUCTION: Composite scores based on psychometrically rigorous cognitive assessments are well suited for early diagnosis and disease monitoring. METHODS: We developed and cross‐validated the Brain Health Assessment‐Cognitive Score (BHA‐CS), based on a brief computerized battery, in 451 cognitively normal (CN) and 399 cognitively impaired (mild cognitive impairment [MCI] or dementia) older adults. We investigated its long‐term reliability and reliable change indices at longitudinal follow‐up (N = 340), and the association with amyloid beta (Aβ) burden in the CN subgroup with Aβ positron emission tomography (N = 119). RESULTS: The BHA‐CS was accurate at detecting cognitive impairment and exhibited excellent long‐term stability. Reliable decline over one year was detected in 75% of participants with dementia, 44% with MCI, and 3% of CN. Among CN, the Aβ‐positive group showed worse longitudinal performance on the BHA‐CS compared to the Aβ‐negative group. DISCUSSION: The BHA‐CS is sensitive to cognitive decline in preclinical and prodromal neurodegenerative disease.