Multi-parameter Diagnostic Blood Test for the Diagnosis of Alzheimer's Disease

Inclusion Criteria: 1. Healthy controls: * Aged between 50-80 years. * Men and women. * Assessment of the neuropsychological tests confirming the absence of cognitive impairment. * Prior to participant inclusion, obtaining the results of the CerebroSpinal Fluid marker analysis (beta-amyloid, Tau protein and p-Tau) carried out in the 24 months before recruitment. 2. Patients diagnosed with Alzheimer's disease (AD). * Aged between 50-80 years. * Men and women. * Patients meet the clinical criteria for Alzheimer's disease: * Prior to participant inclusion, results obtained from CerebroSpinal Fluid marker analysis (beta-amyloid, Tau protein and p-Tau) carried out in the 36 months before recruitment. 3. Patients with behavioural variant frontotemporal dementia and primary progressive aphasia: - * Aged between 50-80 years. * Men and women. * Patient meets the clinical criteria of behavioural variant frontotemporal dementia (bvFTD), or syndromes associated with temporal variants that affect language (primary progressive aphasia, agrammatic and semantic subgroups): (Mild Cognitive Impairment) sub-study: Patients with mild cognitive impairment will be included * Aged between 50-80 years. * Men and women. * Patient meets the clinical criteria for mild cognitive impairment: * Clinical diagnostic criteria for mild cognitive impairment: NIA-Alzheimer's Association of America criteria, Alzheimer's Dementia, 2011 * Prior to participant inclusion, results obtained from cerebrospinal fluid marker analysis (beta-amyloid, Tau protein and p-Tau) carried out in the 12 months before recruitment. Exclusion Criteria: * Severe or acute systemic disease that could impede the participant's follow-up study: Advanced liver or kidney disease and disseminated neoplastic disease * Addiction to alcohol or other drugs in the last two years based on Diagnostic and Statistical Manual of Mental Disorders IV criteria, except nicotine use, which is permitted * Down's syndrome * Moderate or severe head injury * central nervous system infections (HIV, syphilis, borrelia, herpes simplex, suspected Creutzfeldt-Jakob disease) * Endocrine alterations (thyroid alterations) * Nutritional deficiency (vitamin B12, folic acid) * Clinical history of stroke in the previous three months or neuroimaging evidence of clinically significant cardiovascular disease (e.g. strategic infarct or severe leukoencephalopathy). * Neurological diseases (dysmyelinating disorders, Parkinson's disease, Huntington's disease, normal pressure hydrocephalus, subdural haematoma, brain tumours) * Major psychiatric disorder (major depression or psychosis) * Patients who do not have a clearly defined clinical diagnosis according to the study groups (inclusion/exclusion criteria) * Disease which, in the investigator's or sponsor's judgement, may have a potentially significant influence and thus generate bias in the study markers.