Cognitive Function and Prevalence of Amyloid Marker in Frail Older Adults

The COGFRAIL study is a monocentric study integrating the longitudinal follow-up of 345 individuals referred to the Toulouse Frailty Clinic during 2 years. The procedure consists in neuroimaging to diagnose the presence of amyloid plaques in the brains and permit earlier detection of Alzheimer's disease. * Visits will be scheduled at baseline, 1 and 2 years for a full neuropsychological, functional and physical evaluation. * At 6 and 18 months patients will be seen in consultation by a Geriatrician and research assistant for a medical check. * PET-Scan will be scheduled in the 2 months following inclusion for amyloid measurements. The MRI will be proposed, depending on the clinical relevance * A blood sample for biobank will be taken at visit 2 and at the end of the study Extension study (CogFrail-Plus): The extension study will integrate an additional 2 years follow-up of the COGFRAIL study participants, following the initial 2 years period of the study: * 2 Visits will be scheduled at 36 and 48 months for a full neuropsychological, functional and physical evaluation * At 30 and 42 months patients will be seen in consultation by a Geriatrician and research assistant for a medical check * A blood sample will be taken at 36 and 48 months.