Plasma Neurofilament Light Chain Predicts Cognitive Progression in Prodromal and Clinical Dementia with Lewy Bodies

Plasma neurofilament light chain (NfL) is a marker of neuronal damage in different neurological disorders and might predict disease progression in dementia with Lewy bodies (DLB). The study enrolled 45 controls and 44 DLB patients (including 17 prodromal cases) who underwent an extensive assessment at baseline and at 2 years follow-up. At baseline, plasma NfL levels were higher in both probable DLB and prodromal cases compared to controls. Plasma NfL emerged as the best predictor of cognitive decline compared to age, sex, and baseline severity variables. The study supports the role of plasma NfL as a useful prognostic biomarker from the early stages of DLB

A Critical Review of Alien Limb-Related Phenomena and Implications for Functional Magnetic Resonance Imaging Studies

Consensus criteria on corticobasal degeneration (CBD) include alien limb (AL) phenomena. However, the gist of the behavioral features of AL is still “a matter of debate.” CBD-related AL has so far included the description of involuntary movements, frontal release phenomena (frontal AL), or asomatognosia (posterior or “real” AL). In this context, the most frequent symptoms are language and praxis deficits and cortical sensory misperception. However, asomatognosia requires, by definition, intact perception and cognition. Thus, to make a proper diagnosis of AL in the context of CBD, cognitive and language dysfunctions must be carefully verified and objectively assessed. We reviewed the current literature on AL in CBD and now propose that the generic use of the term AL should be avoided. This catchall AL term should instead be deconstructed. We propose that the term AL is appropriate to describe clinical features associated with specific brain lesions. More discrete sets of regionally bound clinical signs that depend on dysfunctions of specific brain areas need to be assessed and presented when posing the diagnosis. Thus, in our opinion, the AL term should be employed in association with precise descriptions of the accompanying involuntary movements, sensory misperceptions, agnosia-asomatognosia contents, and the presence of utilization behavior. The review also offers an overview of functional magnetic resonance imaging-based studies evaluating AL-related phenomena. In addition, we provide a complementary set of video clips depicting CBD-related involuntary movements that should not mistakenly be interpreted as signs of AL

Behavioral and psychological effects of coronavirus disease-19 quarantine in patients with dementia

Background: In March 2020, the World Health Organization declared a global pandemic due to the novel coronavirus SARS-CoV-2 and several governments planned a national quarantine in order to control the virus spread. Acute psychological effects of quarantine in frail elderly subjects with special needs, such as patients with dementia, have been poorly investigated. The aim of this study was to assess modifications of neuropsychiatric symptoms during quarantine in patients with dementia and their caregivers. Methods: This is a sub-study of a multicenter nation-wide survey. A structured telephone interview was delivered to family caregivers of patients with diagnosis of Alzheimer disease (AD), dementia with Lewy bodies (DLB), frontotemporal dementia (FTD), and vascular dementia (VD), followed regularly at 87 Italian memory clinics. Variations in behavioral and psychological symptoms (BPSD) were collected after 1 month since quarantine declaration and associations with disease type, severity, gender, and caregiver\u2019s stress burden were analyzed. Results: A total of 4,913 caregivers participated in the survey. Increased BPSD was reported in 59.6% of patients as worsening of preexisting symptoms (51.9%) or as new onset (26%), and requested drug modifications in 27.6% of these cases. Irritability, apathy, agitation, and anxiety were the most frequently reported worsening symptoms and sleep disorder and irritability the most frequent new symptoms. Profile of BPSD varied according to dementia type, disease severity, and patients\u2019 gender. Anxiety and depression were associated with a diagnosis of AD (OR 1.35, CI: 1.12\u20131.62), mild to moderate disease severity and female gender. DLB was significantly associated with a higher risk of worsening hallucinations (OR 5.29, CI 3.66\u20137.64) and sleep disorder (OR 1.69, CI 1.25\u20132.29), FTD with wandering (OR 1.62, CI 1.12\u20132.35), and change of appetite (OR 1.52, CI 1.03\u20132.25). Stress-related symptoms were experienced by two-thirds of caregivers and were associated with increased patients\u2019 neuropsychiatric burden (p<0.0001). Conclusion: Quarantine induces a rapid increase of BPSD in approximately 60% of patients and stress-related symptoms in two-thirds of caregivers. Health services need to plan a post-pandemic strategy in order to address these emerging needs

Recent Enhancements of Running Behaviour Analysis

Computational techniques allow a very efficient and inexpensive analysis of the running behaviour of railway vehicles. In this paper enhancements related to multibody simulation for three fundamental topics are briefly presented: A software environment for the bifurcation analysis of complex simulation models of arbitrary railway vehicles; consideration of wheelsets’ and rails’ structural electricity within the analysis of the running behaviour; crosswind stability analysis under consideration of parametric variability and uncertainty by reliability analysis

Coupled Multibody-Aerodynamical Simulation of High-Speed Trains Manoeuvres

The effects of aerodynamical loads on the driving dynamics of high speed trains during common manoeuvres have been investigated. To this end a co-simulation MBS/CFD was implemented. A linear aerodynamical model, the panel method, was applied to the computation of the unsteady flow around the driving trailers for the examined manoeuvres in absence of cross wind. The multibody simulation program SIMPACK simulated the dynamical response of the vehicles to the resulting aerodynamical loads. Coupled and uncoupled simulations have been performed. In the uncoupled simulation the aerodynamical loads are computed on trains moving rigidly according to the nominal prescribed driving velocities. The small motion of the trains due to the aerodynamical loads is thus neglected in the aerodynamical subsystem. In the coupled simulations displacements and velocities computed by the multibody code at every time step as effect of the aerodynamics loads are passed back to the aerodynamical code and are embraced in the aerodynamical simulation of the next time step. The effect of operative conditions (different driving velocities, symmetrical and asymmetrical passing manoeuvres) and of environmental conditions (operations on open track or at tunnel entrance) have been investigated, according to the modelling limits imposed by the linear aerodynamical model

Multidisciplinary Probabilistic Risk Analysis of Railway Vehicles in Strong Cross Winds

Strong cross winds can be a source of critical loads on running high speed trains, whose effects depend on the mechanical properties of the vehicles. The originated risk must be accurately evaluated to ensure driving safety without setting unnecessarily severe operative limitations. In this work the traditional deterministic approach to the risk analysis in critically reviewed and a probabilistic approach, which can more efficiently manage the parametric uncertainty and the intrinsic randomness of the problem, is discussed. In particular, the role of computational fluid mechanics and multibody simulations as computational tools is considered

A Problematic Approach to the Effects of Cross-Winds on Rolling Stock

Strong cross-winds can be a source of critical loads on rolling stock, especially for modern lightweight high-speed trains. In this paper some topics of the risk analysis for the cross-wind stability of railway vehicles are discussed. The main tool used to this aim is multibody simulation. The most important input for it must be delivered by an aerodynamic model of the vehicle and of the operating environment. The fact that the parameters in the aerodynamic model can not be detected with sufficient accuracy or can undergo large fluctuations will be focused. This parametric uncertainty is neglected or not properly covered by the conventional risk analysis, which is mainly deterministic. A probabilistic approach, which can address the question more efficiently, is outlined, discussed and presented on a test case

Strömungsmechanische Effekte in der Mehrkörpersimulation bodengebundener Fahrzeuge

Die Berücksichtigung der strömungsmechanischen Effekte in der Mehrkörpersimulation bodengebundener Fahrzeuge wird eingeführt und ein allgemeiner Überblick geliefert. Die Problematik der Kopplung wird in Hinsicht auf konkrete Anwendungen physikalisch beschrieben und formuliert. In Betracht kommen Ähnlichkeiten mit und Unterschiede zur traditionellen Aeroelastik der Tragflächen und schon vorhandenen allgmeinen Methoden. Mögliche Lösungsstrategien für den Spezialfall von Fahrzeugen werden vorgestellt und diskutiert. Schließlich folgt die detailierte Beschreibung eines vielversprechenden und schon in der Aerodynamik angewandten Rechenverfahren, der Panelmethode