Progression of Alzheimer's disease during a three-year follow-up using the CERAD-NB total score: Kuopio ALSOVA study

BACKGROUND: We studied the suitability of The Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Battery (CERAD-NB) total score for monitoring Alzheimer's disease (AD) progression in early-diagnosed medicated patients. We also investigated possible differences in progression between patients with very mild or mild baseline AD. METHODS: In this three-year follow-up of 115 ALSOVA study patients with clinical dementia ratings (CDR) of very mild (0.5) or mild (1) AD, we analyzed total CERAD-NB, Mini-Mental State Examination (MMSE), Neuropsychiatric Inventory (NPI), The Alzheimer's Disease Cooperative Study-Activities of Daily Living Inventory, and Clinical Dementia Rating Sum of Boxes scores. Correlations were identified with efficacy parameters. RESULTS: Over three years, total CERAD-NB declined significantly in both groups. Annual change rates of total CERAD-NB were also significant. Total CERAD-NB revealed annual differences in cognition between study groups, while MMSE did not. Total CERAD-NB correlated well with other cognitive and global measures, but not with NPI. For almost two years, the CDR-0.5 group maintained a higher activities of daily living than the CDR-1 group exhibited at baseline. Furthermore, the CDR-0.5 group showed milder neuropsychiatric symptoms at the end of follow-up than the CDR-1 group showed at baseline. CONCLUSIONS: The CERAD total score is a suitable and sensitive follow-up tool in longitudinal AD trials. Cognition progression rates did not significantly differ between study groups; however, patients with very mild AD at baseline had milder neuropsychiatric symptoms after long-term follow-up. This emphasizes the importance of early diagnosis and assessment of neuropsychiatric symptoms at the diagnostic visit and during follow-up.