Taxonomic and Functional Composition of the Intestinal Microbiome: a Predictor of Rapid Cognitive Decline in Patients With Alzheimer's Disease

Inclusion Criteria: For Alzheimer groups without DCR and Alzheimer with DCR: * patients between 70 and 90 years old * with mild to moderate Alzheimer's disease (MMSE\> 15/30), * followed in the CMRR of the University Hospital of Nantes or Angers * having given their informed consent For the control group (non-Alzheimer's) * more patients between 70 and 90 years * consultant for a subjective memory complaint isolated at the CMRR of Nantes or Angers University Hospital, * having given their informed consent Exclusion Criteria: * Major patients under tutorship, curatorship or safeguard of justice * Cognitive disorders possibly related to a metabolic or psychiatric cause * History of prescription of antibiotic treatment in the last month * History of acute gastrointestinal illness in the last month * History of hospitalization for an acute medical pathology or for a surgical procedure in the last month