Cognitive deterioration in Alzheimer's disease: is the early course predictive of the later stages?

This study investigated the predictive value of the early progression rate of Alzheimer's disease on that of the later stages. We retrospectively evaluated 91 patients affected by possible Alzheimer's disease; the patients had been examined twice with the Milan overall dementia assessment (MODA) scale at an interval of 12 months (53 patients) or 24 months (38 patients). At the first assessment, speed of progression was calculated for each patient dividing the MODA difference from the normality threshold by the time elapsed from the cognitive decline onset. The second assessment of speed of progression was calculated dividing the difference between the two MODA scores by the time elapsed from the first examination. Patients with a slow progression rate in the early stage were unlikely to show a subsequent fast progression rate, and vice versa for patients with a fast early progression. A tool is provided for predicting the speed of cognitive decline of patients from a single MODA assessment. We suggest that, in future clinical trials on Alzheimer's disease, a stratification of participants based on the early rate of cognitive deterioration may be considered.