It will be conducted in an outpatient setting at the tertiary memory clinics (CMRR) in France in patients with a preliminary diagnosis based on the completion of a prior, full diagnostic workup, not more than 12 months previously - which could include, but will not be limited to brain imaging if needed (magnetic resonance imaging (MRI) or computed tomography (CT)), neuropsychological evaluation including a Mini-Mental Status Examination (MMSE), CSF examination and other examinations according to "Haute Autorité de santé" (HAS, National Authority of Health, France) Recommendations - and in whom: