Biomarkers of Sleep-wake Cycle in Prodromal Alzheimer's Disease: Role in Cognitive Decline?

Inclusion Criteria: * Diagnosis of mild Alzheimer's disease with a Mini Mental State (MMS) between 21-30 * The presence of a family carer to complete neuropsychological scales, questionnaires and sleep diaries * Having a neurological assessment and/or follow-up requiring blood and cerebrospinal fluid (CSF) sampling with biomarkers for diagnostic purposes * Patient who had a lumbar puncture less than one year ago or patient with a scheduled lumbar puncture as part of care * Signed informed consent * Able to carry out all visits and follow study procedures * Affiliation to the French social security system Exclusion Criteria: * Genetic form of alzheimer's disease * Insufficient clinical and paraclinical information for the diagnosis of AD * Anticholinesterase and/or memantine treatment or on stable doses for at least 3 months * Use of antidepressants, anxiolytics, hypnotics, neuroleptics, 15 days before inclusion * Patient living in a nursing home * Illiteracy or inability to perform psycho-behavioural tests * Major physical or neurosensory problems that may interfere with the tests * Initial contraindication to diagnostic lumbar puncture (LP) (spinal surgery, skin infection, haemostasis abnormality, intracranial hypertension, severe coagulation disorders, curative anticoagulant therapy, severe liver failure) * Refusal to perform a diagnostic lumbar puncture * Contraindication to the use of E-Celsius: people weighing less than 40 kg, with intestinal disorders, with known swallowing disorders * Patient deprived of liberty, by judicial or administrative decision; * Major protected by law; * Patient in a period of relative exclusion from another protocol or for whom the maximum annual compensation of €4500 has been reached; * Refusal to participate in the protocol.