Eardream Data Collection in Switzerland Supported by ADDF

Participants fulfilling all of the following inclusion criteria are eligible for the study: * Informed Consent as documented by signature * Healthy young adults group: Age range 20-40 * Healthy older adults group: Age range 50-75 * Normal physical and mental status: * Diseases or lesions of the nervous system (acute or residual included neurological and psychiatric diseases) * Clinically significant concomitant disease states (e.g., renal failure, hepatic dysfunction, cardiovascular disease, etc.) * Sleep disorders, known or suspected (e.g. Insomnia, sleep apnoea, restless leg syndrome, narcolepsy, etc.) * mini mental state examination (MMSE) score \> 24) * Native German speaker or good understanding of German Participants are not eligible if the fulfil the following exclusion criteria: * Direct relatives have not been diagnosed with neuropathological conditions associated with any form of dementia (e.g., AD, MCI) * Participation in another study with investigational drug/therapy/interventions within the 30 days preceding and during the present study (start date adapted accordingly) * Shift-work (e.g. work times 12am-5am) * Suspected drug- or medication abuse, or on-label sleep medication use during time of the study * Infection/disease of auditory canal or ear drum that could worsen with EAR-DREAM application, or allergies to in-Ear electrode materials (e.g., silver) * Pregnancy (not safety related, but relevant for data interpretation procedures given that pregnancy can result in sleep patterns that are different from the baseline measurements that we intend to characterize) Additional non-medical exclusion criteria may be defined for certain cognitive tasks (e.g. no glasses during experiments involving pupillometry).