[The Alzheimer's disease: how to estimate the impact of the pathology and the treatment?].

The Alzheimer's disease (AD) is a neuro-degenerative pathology which establishes at present the most frequent cause of dementia. The therapeutic which we have actually are symptomatic treatments which do not modify the evolution of the disease. A clinical and cognitive evaluation is sufficient mostly to estimate the efficiency of these symptomatic treatments. The development of treatments to modify the natural evolution of AD (disease modifying) requires the implementation of innovative therapeutic tries with a significant number of subjects, a long period of observation and where the only clinical criteria of evaluation seem insufficient. The use of biomarkers of plasma, cerebrospinal fluid, or neuro-imaging could play an important role to estimate their efficiency. However, at present no biomarker is validated as surrogate endpoint. It seems today indispensable to use them in the therapeutic tries so as to validate and standardize their methods of acquisition, measure and analysis.