Digitally-enhanced, Decentralized, Multi-omics Observational Cohort

Inclusion Criteria for Cohort participants: * Male or female over 45 years of age. * Subject is seen at a memory clinic or is part of an observational study. * An informant (caregiver/family member) is available to collaborate. * Diagnosis of individuals in the AD biological continuum with evidence of amyloid-beta accumulation based on the presence of Aβ load AD biomarkers (either in CSF or PET scan), MMSE, CDR score and cognitive tests as defined by the Guidance document of EMA (2016) or FDA (2018): * preclinical AD: MMSE≥27 and CDR=0, either none or borderline cognitive deficits (compatible with FDA stages 1 and 2, with positive AD biomarkers). Patients reporting subjective cognitive decline who meet the criteria above are eligible for assignment to the preclinical AD group. * prodromal AD/MCI due to AD: MMSE \>23, CDR=0.5, impairment on cognitive testing with RBANS (compatible with stage 3 FDA, with positive AD biomarkers). * Prodromal PD: Male or female age 60 years or older (except age 30 years or older for SNCA, or rate genetic mutations (such as Parkin or Pink1) participants). * Individuals taking any of the following drugs: alpha methyldopa, methylphenidate, amphetamine derivatives or modafinil, must be willing and medically able to hold the medication for at least 5 half-lives before DaTscan imaging. * Informed consent signed by the subject and informant. * Informant should be able to read and communicate in the language of the recruitment centre and available to actively engage in tests and questionnaires. * Subject and the informant own a smartphone. Inclusion Criteria for Healthy volunteers: * Male or female over 45 years of age. * Individuals with no evidence of amyloid-beta accumulation based on the presence of Aβ load AD biomarkers (either in CSF or PET scan). * Approximately age and gender matched to AD subjects on a group level. * An informant is available to collaborate. * MMSE \>27, CDR=0. * In otherwise good health conditions, or with diagnosis mild chronic disorders (of metabolic, respiratory, immunological, cardiologic, and metabolic origin) or any other affections that are controlled by the therapy and do not importantly limit ADLs or social interactions. * Able to read and to communicate in the language of the recruitment centre. * nformed consent signed by the subject and caregiver. * Subject and informant own a smartphone. Exclusion Criteria for Cohort participants: * Presence of an additional neurological or psychiatric disease that may affect ADL, cognitive function or social interactions. * Clinical diagnosis of PD, other parkinsonism, or dementia. * Received any of the following drugs: dopamine receptor blockers (neuroleptics), metoclopramide and reserpine within 6 months of Screening visit. * Current treatment with anticoagulants (e.g. coumadin, heparin) that might preclude safe completion of the lumbar puncture. * Abnormal VB12 value. * Any other kind of disorders that relevantly affect mobility and/or ADL, cognitive function or social interactions (e.g., immune-mediated inflammatory disorders, recovery from recent trauma, stroke, etc.). * TSH above normal range * T3 or T4 outside normal range with clinically significant. Exclusion Criteria for Healthy volunteers: * Presence of an additional neurological or psychiatric disease that may affect ADL, cognitive function or social interactions. * Diagnosis of any disorders or post traumatic conditions that are not fully controlled by the therapy and produce relevant limitations of ADL, cognitive function or social interactions.