Single-center Prospective Longitudinal Study of Taste in Patients With Cognitive Disorders at Different Stages of Severity (Isolated Cognitive Complaint, Minor or Major Neurocognitive Alzheimer-type Disorders) by Analysis of Gustatory Evoked Potentials

Inclusion Criteria: * Person who has given oral consent. * For patients with mild to moderate Alzheimer\'s disease, the primary caregiver and the patient will be asked to provide oral consent * Person of legal age * Body Mass Index (BMI) \< 30 kg/m². * For the healthy group: absence of cognitive complaints and normal neurological assessment * Patients meeting the criteria for isolated cognitive complaint: presence of cognitive complaint but normal neuropsychological evaluation * Patients meeting diagnostic criteria for minor cognitive impairment: imaging (brain MRI) and neuropsychological assessment with a Clinical Dementia Rating (CDR) score of 0.5 * Patients meeting diagnostic criteria for mild to moderate Alzheimer\'s disease: imaging (brain MRI), neuropsychobiological criteria (consultation with neuropsychological assessment, CSF biomarkers), MMSE score ≥ 20 and CDR score of 1 or 1.5 * Fasting for at least 2 hours before GEP measurement Exclusion Criteria: * MMSE score\<15 * Known COVID-19 infection within 6 months prior to inclusion * Person not affiliated to national health insurance system * Person under a legal protection measure (curatorship, guardianship) * Person subject to a measure of legal protection * Pregnant, parturient or breastfeeding women * Subjects with a pacemaker (contraindication to bioelectrical impedance measurement) * Adult unable to express consent or to perform cognitive tests. * Active smoker (\> 4 cigarettes per day on a regular basis) * Diabetic subject (type 1 or type 2) * Subject with acute or chronic ENT disease * Treatment interfering with gustation * Brain MRI showing another cause of neurocognitive disorder (except for vascular lesions Fazekas 1 accepted)