Amyloïd Load in Elderly Population: Effect of Cognitive Reserve

Inclusion Criteria: Participation in the AMI or 3C cohorts Group 1- Controls * MMSE \> 24 or \> 26 for low and high levels of education, respectively. * Without memory impairment (for episodic memory) on the Free and Cued Selective Reminding Test RL/RI-16 items (FCSRT), free recall \> 22 and total recall \>42, according to the thresholds for population-based studies * Without memory complaint * Without dementia Group 2- Cognitively-impaired subjects without dementia and without memory complaints * Mini Mental State Evaluation (MMSE) \< 24 or \< 26 for low and high levels of education, respectively * With memory impairments according to the RL/RI-16 test (free recall≤22 and/or total recall ≤42), according to the thresholds for population-based studies defined by Auriacombe et al., 2010. * Without memory complaint * Without dementia Group 3- Cognitively-impaired subjects without dementia and with memory complaints * MMSE \< 24 or \< 26 for low and high levels of education, respectively * With memory impairments according to the RL/RI-16 test (same thresholds as above) * With memory complaint * Without dementia Exclusion Criteria: * Being left handed * Presence of dementia (based on the clinical diagnosis) * Presence of stroke * Presence of Parkinson's disease * Presence of a counter-indication for MRI * Presence of a counter-indication for PET Scan with \[18F\]-Flutemetamol * Presence of any health problem preventing travel to the imaging service of the University Hospital * Being under the legal guardianship of another person or being unable to provide consent to participate * Pregnant or breastfeeding woman