Preclinical detection of Alzheimer's disease pathology using conceptual discrimination abilities.

Background: Performance on the Conceptual Matching Task (CMT), a measure of discrimination between conceptually confusable items, has been suggested as a cognitive marker of rhinal cortex atrophy, one of the first brain regions affected by Alzheimer's disease (AD) pathology.

Objectives: We aimed to determine whether CMT can detect preclinical AD, and whether CMT performance is related to regional deposition of tau protein or other AD-associated lesions including amyloid (Aβ) accumulation and white matter hyperintensities (WMH).

Design, Setting And Participants: This cross-sectional study include 101 participants from the UCL2016-121 cohorts in Brussels, Belgium, classified as 56 Aβ-negative cognitively unimpaired (Aβ-CU), 25 Aβ-positive CU (Aβ+CU, preclinical AD), and 20 Aβ-positive mildly cognitively impaired (Aβ+MCI, prodromal AD) individuals.

Independent validation and outlier analysis of EuroPOND alzheimer's disease staging model using ADNI and real-world clinical data.

Background: Event-based modeling (EBM) traces sequential progression of events in complex processes like neurodegenerative diseases, adept at handling uncertainties. This study validated an EBM for Alzheimer's disease (AD) staging designed by EuroPOND, an EU-funded Horizon 2020 project, using research and real-world datasets, a crucial step towards application in multi-center trials.

Methods: The training dataset comprised 1737 subjects from ADNI-1/GO/2, using the EuroPOND EBM toolbox.

Entorhinal tau impairs short-term memory binding in preclinical Alzheimer's disease.

Objective: The entorhinal cortex (EC) is the first cortical region affected by tau pathology in Alzheimer's disease (AD), but its functions remain unclear. The EC is thought to support memory binding, which can be tested using the Visual Short-Term Memory Binding Test (VSTMBT). We aimed to test whether VSTMBT performance can identify individuals with preclinical AD before noticeable episodic memory impairment and whether these performances are related to amyloid (Aβ) pathology and/or EC tau burden.

Unfamiliar facial identity discrimination and recognition impairment in prodromal Alzheimer's disease: A behavioral pattern separation and completion study.

Background: Impairment of face identity recognition (FIR) in prodromal Alzheimer's disease (AD) is not clearly established, and the cognitive processes underpinning a potential FIR impairment remain elusive. The influential pattern separation (PS) and completion (PC) framework may offer a fascinating insight in this respect. Indeed, efficient FIR implies PS to encode facial identities in distinct memory representations, while PC is involved in matching the perceived facial patterns to these memory representations at retrieval.

Tau PET Imaging With [F]MK-6240: Limited Affinity for Primary Tauopathies and High Specificity for Alzheimer's Disease.

Introduction: Second-generation tau-PET tracers like [F]MK-6240 are increasingly used both for diagnosing and quantifying Alzheimer's Disease (AD) tauopathy. However, while [F]MK-6240 tau-PET has demonstrated excellent sensitivity for AD tauopathy, data assessing its specificity and binding in non-AD tauopathies are still scarce.

Methods: Participants were assigned to exclusive categorical diagnoses based on their amyloid (Aβ) and cognitive status.

Rotation errors in path integration are associated with Alzheimer's disease tau pathology: a cross-sectional study.

Background: Early Alzheimer's disease diagnosis is crucial for preventive therapy development. Standard neuropsychological evaluation does not identify clinically normal individuals with brain amyloidosis, the first stage of the pathology, defined as preclinical Alzheimer's disease. Spatial navigation assessment, in particular path integration, appears promising to detect preclinical symptoms, as the medial temporal lobe plays a key role in navigation and is the first cortical region affected by tau pathology.

An objective and sensitive electrophysiological marker of word semantic categorization impairment in Alzheimer's disease.

Objective: Combining electroencephalographic (EEG) recording and fast periodic visual stimulation (FPVS) to provide an implicit, objective and sensitive electrophysiological measure of semantic word categorization impairment in Alzheimer's Disease (AD).

Methods: Twenty-five AD patients and 25 matched elderly healthy controls were tested with a validated FPVS-EEG paradigm in which different written words of the same semantic category (cities) appear at a fixed frequency of 4 words per second (4 Hz) for 70 seconds. Words from a different semantic category (animal) appear every 4 stimuli (i.

Amyloid-PET imaging predicts functional decline in clinically normal individuals.

Background: There is good evidence that elevated amyloid-β (Aβ) positron emission tomography (PET) signal is associated with cognitive decline in clinically normal (CN) individuals. However, it is less well established whether there is an association between the Aβ burden and decline in daily living activities in this population. Moreover, Aβ-PET Centiloids (CL) thresholds that can optimally predict functional decline have not yet been established.

Serum Neurofilament Light and Postoperative Delirium in Cardiac Surgery: A Preplanned Secondary Analysis of a Prospective Observational Study.

Background: Impaired cognition is a major predisposing factor for postoperative delirium, but it is not systematically assessed. Anesthesia and surgery may cause postoperative delirium by affecting brain integrity. Neurofilament light in serum reflects axonal injury.

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.

The spatial extent of tauopathy on [F]MK-6240 tau PET shows stronger association with cognitive performances than the standard uptake value ratio in Alzheimer's disease.

Purpose: [F]MK-6240, a second-generation tau PET tracer, is increasingly used for the detection and the quantification of in vivo cerebral tauopathy in Alzheimer's disease (AD). Given that neurological symptoms are better explained by the topography rather than by the nature of brain lesions, our study aimed to evaluate whether cognitive impairment would be more closely associated with the spatial extent than with the intensity of tau-PET signal, as measured by the standard uptake value ratio (SUVr).

Methods: [F]MK6240 tau-PET data from 82 participants in the AD spectrum were quantified in three different brain regions (Braak ≤ 2, Braak ≤ 4, and Braak ≤ 6) using SUVr and the extent of tauopathy (EOT, percentage of voxels with SUVr ≥ 1.

Suspecting Non-Alzheimer's Pathologies and Mixed Pathologies: A Comparative Study Between Brain Metabolism and Tau Images.

Background: Alzheimer's disease (AD) pathology can be disclosed in vivo using amyloid and tau imaging, unlike non-AD neuropathologies for which no specific markers exist.

Objective: We aimed to compare brain hypometabolism and tauopathy to unveil non-AD pathologies.

Methods: Sixty-one patients presenting cognitive complaints (age 48-90), including 32 with positive AD biomarkers (52%), performed [18F]-Fluorodeoxyglucose (FDG)-PET (brain metabolism) and [18F]-MK-6240-PET (tau).

Intra-operative electroencephalogram frontal alpha-band spectral analysis and postoperative delirium in cardiac surgery: A prospective cohort study.

Background: Postoperative delirium (POD) remains a frequent complication after cardiac surgery, with pre-operative cognitive status being one of the main predisposing factors. However, performing complete pre-operative neuropsychological testing is challenging. The magnitude of frontal electroencephalographic (EEG) α oscillations during general anaesthesia has been related to pre-operative cognition and could constitute a functional marker for brain vulnerability.

Case report: Motor neuron disease phenotype associated with symptomatic copper deficiency: Challenging diagnosis and treatment.

Copper deficiency is an acquired condition that can lead to neurologic dysfunctions, such as myelopathy, motor neuron impairment, polyneuropathy, cognitive impairment, and optic nerve neuropathy. Associated biological findings are low serum copper and ceruloplasmin levels with low copper urinary excretion. We report the case of a previously healthy 59-year-old man who presented a complex neurological picture starting with symptoms and radiological signs consistent with degenerative myelopathy in the presence of persisting low serum copper and ceruloplasmin despite oral and intravenous copper supplementation.

Alzheimer disease's cerebrospinal fluid biomarkers differences between immigrants and natives in a Belgian memory clinic.

Background: Diagnosis of neurodegenerative diseases can raise difficulties among immigrant patients due to language, educational or sociocultural differences with natives. CSF biomarkers of Alzheimer's disease are useful tools to early diagnose neurodegeneration. Yet very few studies have investigated differences of those biomarkers between immigrant and native populations.

Investigating the Origin of TMS-evoked Brain Potentials Using Topographic Analysis.

The combination of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) represents an increasingly popular tool to non-invasively probe cortical excitability in humans. TMS-evoked brain potentials (TEPs) are composed of successive components reflecting the propagation of activity from the site of stimulation, thereby providing information on the state of brain networks. However, TMS also generates peripherally evoked sensory activity which contributes to TEP waveforms and hinders their interpretation.

Default-Mode Network Connectivity Changes During the Progression Toward Alzheimer's Dementia: A Longitudinal Functional Magnetic Resonance Imaging Study.

Brain function changes with Alzheimer's disease (AD) progression. Evaluating those changes longitudinally is important to understand the complex relationships between brain pathologies and cognition. We aimed (1) to identify longitudinal changes in functional connectivity in patients with mild cognitive impairment (MCI) characterized for amyloid-β (Aβ) status and (2) to relate these functional changes to clinical progression.

Diagnostic Performance of Automated MRI Volumetry by icobrain dm for Alzheimer's Disease in a Clinical Setting: A REMEMBER Study.

Background: Magnetic resonance imaging (MRI) has become important in the diagnostic work-up of neurodegenerative diseases. icobrain dm, a CE-labeled and FDA-cleared automated brain volumetry software, has shown potential in differentiating cognitively healthy controls (HC) from Alzheimer's disease (AD) dementia (ADD) patients in selected research cohorts.

Objective: This study examines the diagnostic value of icobrain dm for AD in routine clinical practice, including a comparison to the widely used FreeSurfer software, and investigates if combined brain volumes contribute to establish an AD diagnosis.

Spouse-Appraised Memory Functioning Predicts Memory Decline Better Than Subjective Memory Complaints in Community Dwelling Older Adults at Genetic Risk for Alzheimer's Disease.

Alzheimer's disease (AD) begins with subtle memory decline, years before dementia onset. The presence of subjective memory complaints (SMC) has been proposed as a marker of preclinical AD. However, recent evidence has demonstrated early and progressive loss of awareness of memory difficulties in non-demented older adults harboring AD pathology.

Frontotemporal dementia patients exhibit deficits in predictive saccades.

Prediction and time estimation are all but required for motor function in everyday life. In the context of eye movements, for instance, they allow predictive saccades and eye re-acceleration in anticipation of a target re-appearance. While the neural pathways involved are not fully understood, it is known that the frontal lobe plays an important role.