This study is a first in man study investigating the feasibility of the collection, storage, processing and analysis of 4 key biomarkers for the diagnosis of Alzheimer's disease [AD] in nasal secretion. Nasal secretion [NS] constitutes a minimally invasive access to cerebrospinal fluid [CSF]. Therefore, it could be highly suitable for detection and monitoring of the AD relevant biomarkers pTau181, total Tau, Amyloid-ß1-40 and Amyloid-ß1-42. This study evaluates correlations of biomarker patterns in NS and CSF. Furthermore, the correlations of the 4 AD specific biomarkers in nasal secretion and CSF is investigated. For this study, patients with cognitive impairment (AD and NonAD group) and healthy controls were included.

Inclusion Criteria:

• Group A Patient WITH cognitive impairment and no nasal pathologies. CSF analysis is planned or results are already available
• Group B Patient WITHOUT cognitive disorder and without pathologies in the nasal area

Exclusion Criteria:

• Presence of an obstructing nasal cavity disease
• Patient suffers from an acute upper respiratory tract infection (putrid rhinorrhea)
• Inability to give consent