Clinical Manifestations.

Background: The ability to discriminate very similar objects by implementing the binding between their multiple features is assumed to be supported by the medial temporal lobe (MTL). MTL is the first brain region that shows abnormal tau accumulation in Alzheimer's disease (AD). However, whether binding ability is impaired since the preclinical stage of AD and relates to MTL tau burden is not well-established.

Clinical Manifestations.

Background: The medial temporal lobe (MTL) is the first cortical region affected by tauopathy in Alzheimer's disease (AD) and is implicated in spatial orientation. In early AD stages, navigation deficits, including path integration deficits, could be present, even before memory deficits. We investigated whether these deficits were related to AD pathology (amyloidosis and/or tauopathy) using a path integration task, the "Apple Game".

Comparison of plasma soluble and extracellular vesicles-associated biomarkers in Alzheimer's disease patients and cognitively normal individuals.

Background: Amyloid-β (Aβ) and tau are brain hallmarks of Alzheimer's disease (AD), also present in blood as soluble biomarkers or encapsulated in extracellular vesicles (EVs). Our goal was to assess how soluble plasma biomarkers of AD pathology correlate with the number and content of EVs.

Methods: Single-molecule enzyme-linked assays were used to quantify Aβ42/40 and tau in plasma samples and neurally-derived EVs (NDEVs) from a cohort of APOE ε4- (n = 168) and APOE ε4+ (n = 68) cognitively normal individuals and AD patients (n = 55).

Definition of a Threshold for the Plasma Aβ42/Aβ40 Ratio Measured by Single-Molecule Array to Predict the Amyloid Status of Individuals without Dementia.

Alzheimer's disease (AD) is characterized by amyloid beta (Aβ) plaques and hyperphosphorylated tau in the brain. Aβ plaques precede cognitive impairments and can be detected through amyloid-positron emission tomography (PET) or in cerebrospinal fluid (CSF). Assessing the plasma Aβ42/Aβ40 ratio seems promising for non-invasive and cost-effective detection of brain Aβ accumulation.

Specific post-translational modifications of soluble tau protein distinguishes Alzheimer's disease and primary tauopathies.

Tau protein aggregates in several neurodegenerative disorders, referred to as tauopathies. The tau isoforms observed in post mortem human brain aggregates is used to classify tauopathies. However, distinguishing tauopathies ante mortem remains challenging, potentially due to differences between insoluble tau in aggregates and soluble tau in body fluids.