The objective is to demonstrate a correlation between oxidative stress and nutrition biomarkers and the clinical evolution of patients complaining of cognitive impairments. In this study, the principal evaluation criteria will be the MMSE score evolution during the 60 months of the patients follow-up, measured during the routine visits scheduled approximately every 6 months, according to the french national authority for health recommendations. It will allow evaluating the correlation between the cognitive decline evolution measured by MMSE during the Alzheimer disease or related diseases method during the 2 years follow-up, and the oxidative stress blood markers.