Apport des biomarqueurs cognitifs dans le diagnostic de la maladie d'Alzheimer

The diagnosis of Alzheimer's disease still relies on a neuropathological confirmation. Although there is no absolute concordance between clinical signs and underlying pathology, careful clinical phenotyping often allows prediction of histopathological change with a high level of accuracy. Many studies are currently attempting to improve the identification of patients with early Alzheimer's disease, when neuropathological change is minimal. Neurodegenerative diseases selectively target neuronal networks. The identification of these neuronal networks is crucial for diagnosis in general, but especially for early diagnosis. Based on the sequential stages related to the progression of neurofibrillary tangles within the mesial temporal lobe, we recently suggested that the earliest, or transentorhinal stage of Alzheimer's disease, results in dysfunction of an anterior mesiotemporal network characterized by impaired context-free memory (memory for facts), while the subsequent dysfunction of the posterior mesiotemporal network results in dysfunction of context-rich (episodic) memory. We report on a translational approach based on pathophysiological data in Alzheimer's disease to suggest that cognitive processes reflecting dysfunction of neural networks that are the target of pathological change could lead to the development of “cognitive biomarkers” reflecting neural dysfunction on a clinical level.