Diffusion Tensor Imaging in Alzheimer's disease

Attentional control and Information processing speed are central concepts in cognitive psychology and neuropsychology. Functional neuroimaging and neuropsychological assessment have depicted theoretical models considering attention as a complex and non-unitary process. One of its component processes, Attentional set-shifting ability, is commonly assessed using the Trail Making Test (TMT). Performance in the TMT decreases with increasing age in adults, Mild Cognitive Impairment (MCI) and Alzheimer’s Disease (AD). Besides, speed of information processing (SIP) seems to modulate attentional performance. While neural correlates of attentional control have been widely studied, there are few evidences about the neural substrates of SIP in these groups of patients. Different authors have suggested that it could be a property of cerebral white matter, thus, deterioration of the white matter tracts that connect brain regions related to set-shifting may underlie the age-related, MCI and AD decrease in performance. The aim of this study was to study the anatomical dissociation of attentional and speed mechanisms. Diffusion tensor imaging (DTI) provides a unique insight into the cellular integrity of the brain, offering an in vivo view into the microarchitecture of cerebral white matter. At the same time, the study of ageing, characterized by white matter decline, provides the opportunity to study the anatomical substrates speeded or slowed information processing. We hypothesized that FA values would be inversely correlated with time to completion on Parts A and B of the TMT, but not the derived scores B/A and B-A

The Vallecas Project: a cohort to identify early markers and mechanisms of Alzheimer's disease

Alzheimer’s disease (AD) is a major threat for the well-being of an increasingly aged world population. The physiopathological mechanisms of late-onset AD are multiple, possibly heterogeneous, and not well understood. Different combinations of variables from several domains (i.e., clinical, neuropsychological, structural, and biochemical markers) may predict dementia conversion, according to distinct physiopathological pathways, in different groups of subjects

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

A novel workflow correlating RNA-seq data to Phythophthora infestans resistance levels in wild Solanum species and potato clones

Comparative transcriptomics between species can provide valuable understanding of plant-pathogen interactions. Here, we focus on wild Solanum species and potato clones with varying degree of resistance against Phytophthora infestans, which causes the devastating late blight disease in potato. The transcriptomes of three wild Solanum species native to Southern Sweden, S. dulcamara, S. nigrum and S. physalifolium were compared to three potato clones, Desiree (cv.), SW93-1015 and Sarpo Mira. Desiree and S. physalifolium are susceptible to P. infestans whereas the other four have different degrees of resistance. By building transcript families based on de novo assembled RNA-seq across species and clones and correlating these to resistance phenotypes, we created a novel workflow to identify families with expanded or depleted number of transcripts in relation to the P. infestans resistance level. Analysis was facilitated by inferring functional annotations based on the family structure and semantic clustering. More transcript families were expanded in the resistant clones and species and the enriched functions of these were associated to expected gene ontology (GO) terms for resistance mechanisms such as hypersensitive response, host programmed cell death and endopeptidase activity. However, a number of unexpected functions and transcripts were also identified, for example transmembrane transport and protein acylation expanded in the susceptible group and a cluster of Zinc knuckle family proteins expanded in the resistant group. Over 400 expressed putative resistance (R-)gene were identified and resistant clones Sarpo Mira and SW93-1015 had ca 25% more expressed R-genes than susceptible cultivar Desiree. However, no differences in numbers of susceptibility (S-)gene homologs were seen between species and clones. In addition, we identified P. infestans transcripts including effectors in the early stages of P. infestans-Solanum interactions

Psychometric properties of a new short version of the State-Trait Anxiety Inventory (STAI) for the assessment of anxiety in the elderly

Introduction: Anxiety has negative effects on the cognitive performance and psychosocial adjustment of elderly people. Given the high prevalence of anxiety symptoms in patients suffering from cognitive impairment, it has been suggested that these symptoms may be an early marker of dementia. The State-Trait Anxiety Inventory (STAI) is one of the widely-used used scales for evaluating anxiety in elderly people. However, inasmuch as the STAI may be difficult to apply to older people, having a short form of it would be desirable. Methods: The participants comprised 489 community-dwelling individuals aged 68 years and over. All of them were volunteers in a longitudinal study for early detection of Alzheimer’ Disease (Proyecto Vallecas). The full sample was divided in two homogeneous subgroups: Group A, used to reduce the number of items and response options, and Group B, the group used to determine the psychometric properties of the new short form (STAIr). Results: A dichotomous Rasch model was used to obtain the STAIr. No statistically significant differences for STAIr scores were found with respect to sociodemographic variables. Psychometric properties and normative data were obtained for the new short-version. Conclusions: The STAIr is composed of 13 items and data fits the model well. Since it is short and easy to apply to elderly people, STAIr will be very useful in clinical and research settings. Resumen: Introducción: La ansiedad tiene efectos negativos sobre el rendimiento cognitivo y el ajuste psicosocial de las personas mayores. Dada la elevada prevalencia de los síntomas de ansiedad en personas con deterioro cognitivo, se ha indicado que podrían ser un marcador precoz de demencia. Una de las pruebas más utilizadas para valorar el nivel de ansiedad en personas mayores es el Inventario de Ansiedad Estado-Rasgo (STAI). No obstante, en la medida en que puede resultar una escala larga para los mayores, sería deseable contar con una versión abreviada de la misma. Métodos: Se reclutó una muestra de 489 participantes mayores de 68 años cognitivamente sanos, todos ellos eran voluntarios en un proyecto de investigación longitudinal sobre la enfermedad de Alzheimer (Proyecto Vallecas). La muestra se subdividió en 2 grupos homogéneos: el grupo A se utilizó para reducir el número de ítems y de opciones de respuesta, y el grupo B para obtener las propiedades psicométricas de la nueva escala reducida (STAIr). Resultados: Se empleó el modelo de Rasch dicotómico para obtener el STAIr. Las variables sociodemográficas no mostraron asociación con las puntuaciones de la nueva versión. Se estudiaron las propiedades psicométricas y se hallaron los datos normativos del STAIr. Conclusiones: La nueva versión STAIr se compone de 13 ítems y presenta una adecuada bondad psicométrica. En la medida en que es una escala rápida y sencilla para las personas mayores, su aplicación resulta útil en los contextos clínico e investigador. Keywords: Anxiety, Cognitive impairment, Ageing, Neuropsychological assessment, State-Trait Anxiety Inventory, Item response theory, Palabras clave: Ansiedad, Deterioro cognitivo, Envejecimiento, Evaluación neuropsicológica, Inventario de Ansiedad Estado-Rasgo, Teoría de respuesta al íte