Rate of progression of mental decline in Alzheimer disease: summary of European studies.

The aim of this study was to provide an update on the rate of progression in Alzheimer disease. In particular, we conducted a survey on European longitudinal studies that focused on the course of the disease and were performed since 1992. By means of Medline search and review papers and by personal contact with principal investigators, a census of existing studies on natural history of the disease in Europe has been carried out. We present data arising from our search and discuss methodological aspects by comparing data available from U.S. studies on disease progression and implications for clinical trials.