Plasma p-tau217 predicts cognitive impairments up to ten years before onset in normal older adults.

Importance: Positron emission tomography (PET) biomarkers are the gold standard for detection of Alzheimer amyloid and tau . Such imaging can identify cognitively unimpaired (CU) individuals who will subsequently develop cognitive impartment (CI). Plasma biomarkers would be more practical than PET or even cerebrospinal fluid (CSF) assays in clinical settings.

Association of Serum Brain-Derived Tau With Clinical Outcome and Longitudinal Change in Patients With Severe Traumatic Brain Injury.

Importance: Blood-based measurements of total tau (T-tau) are commonly used to examine neuronal injury in patients with traumatic brain injury (TBI), but current assays do not differentiate between brain-derived tau (BD-tau) and tau produced in peripheral tissues. A novel assay for BD-tau has recently been reported that selectively quantifies nonphosphorylated tau of central nervous system origin in blood samples.

Objectives: To examine the association of serum BD-tau with clinical outcomes in patients with severe TBI (sTBI) and its longitudinal changes over 1 year.

Longitudinal blood biomarker trajectories in preclinical Alzheimer's disease.

Introduction: Plasma biomarkers are altered years prior to Alzheimer's disease (AD) clinical onset.

Methods: We measured longitudinal changes in plasma amyloid-beta (Aβ) ratio, pTau181, pTau231, neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP) in a cohort of older adults at risk of AD (n = 373 total, n = 229 with Aβ and tau positron emission tomography [PET] scans) considering genetic and demographic factors as possible modifiers of these markers' progression.

Results: Aβ ratio concentrations decreased, while NfL and GFAP values increased over the 4-year follow-up.

Subjective difficulty in a verbal recognition-based memory task: Exploring brain-behaviour relationships at the individual level in healthy young adults.

The vast majority of fMRI studies of task-related brain activity utilize common levels of task demands and analyses that rely on the central tendencies of the data. This approach does not take into account perceived difficulty nor regional variations in brain activity between people. The results are findings of brain-behavior relationships that weaken as sample sizes increase.

Plasma p-tau231, p-tau181, PET Biomarkers, and Cognitive Change in Older Adults.

Objective: The objective of this study was to evaluate novel plasma p-tau231 and p-tau181, as well as Aβ and Aβ assays as indicators of tau and Aβ pathologies measured with positron emission tomography (PET), and their association with cognitive change, in cognitively unimpaired older adults.

Methods: In a cohort of 244 older adults at risk of Alzheimer's disease (AD) owing to a family history of AD dementia, we measured single molecule array (Simoa)-based plasma tau biomarkers (p-tau231 and p-tau181), Aβ and Aβ with immunoprecipitation mass spectrometry, and Simoa neurofilament light (NfL). A subset of 129 participants underwent amyloid-β ( F-NAV4694) and tau ( F-flortaucipir) PET assessments.