[Biomarkers of the Alzheimer's disease: concepts and clinical case]

Concepts and knowledge evolve gradually our ways of diagnosing and treating many diseases, but also our views and some kind of stigmatization that could be associated with them. Alzheimer's disease seems to evolve over several years before leading any perceptible clinical sign. To redefine its semantics seems thus essential. This way, new diagnostic criteria should allow refining diagnosis in case of dementia but also and especially before the apparition of any clinical manifestations or in case of mild suggestive cognitive disorders. Moreover, they allow, in case of other cognitive disorders presentations (aphasia or apraxia), diagnosing its unusual atypical form. However, the possibility that they also offer to set such diagnosis of Alzheimer's disease to people who do not present any slights clinical signs raises numerous ethical considerations, especially in view of the current absence of curative treatment. Noteworthy that, in theory, a biomarker is the objective indicator of a biological process associated with the pathogenicity. In Alzheimer's disease, pathogenicity and scientific bases to propose these biomarkers remains at least controversial. All of these crucial questions leading to their exclusive use by team specialized in their practices and interpretations. An exemplary clinical case is presented.