A 2-year follow-up of 233 very mild (CDR 0.5) Alzheimer's disease patients (REAL.FR cohort).

OBJECTIVES: Making an early diagnosis of Alzheimer's Disease (AD) is becoming increasingly important. The Clinical Dementia Rating scale (CDR), a semi-structured interview with patient and caregiver, is a global rating scale designed for use in staging dementia. The primary objective of our study was to examine the evolution of AD in individuals with very mild AD (CDR 0.5) across a 2-year follow up.

METHODS: A cohort of AD patients (n=682) living in the community were followed during 2 years in 16 centres of the French AD network. Each subject underwent extensive medical examination including the MMSE and CDR every 6 months.

RESULTS: Two hundred and thirty-three AD patients were rated CDR 0.5 at baseline (mean MMSE score: 23.15+/-2.57). They were younger and reported an average duration of symptoms of approximately 0.8 years less than patients with CDR >or= 1.During the 2-year follow-up, none of the AD CDR 0.5 subjects improved; 65% of them showed an increase in the CDR score. The rate of cognitive decline was similar between the AD CDR 0.5 and CDR >or= 1 groups. The ADL decline was more significant in patients with CDR >or= 1 at inclusion.

CONCLUSIONS: It is certainly possible to identify AD at a very early stage focusing on intra individual change in cognitive and functional impairment. Criteria with a high sensitivity and specificity for detecting AD at an early stage will help to further develop effective pharmacological and behavioural interventions for delaying the onset and progression of the disease.