The cardiopulmonary hemodynamic profile observed during exercise may identify patients with early stage pulmonary vascular and primary cardiac diseases, and is used clinically to inform prognosis. However, a standardised approach to interpreting hemodynamics is lacking.We performed a systematic literature search according to PRISMA guidelines to identify parameters that may be diagnostic for an abnormal hemodynamic response to exercise and offer optimal prognostic and differential-diagnostic value. We performed random-effects-meta-analyses of the normal values and reported effect sizes as weighted means and standard deviations (sd). Results of diagnostic and prognostic studies are reported descriptively.We identified n=45 eligible studies with n=5598 subjects. The mean pulmonary arterial pressure (mPAP)/cardiac output (CO) slope, pulmonary arterial wedge pressure (PAWP)/CO slope and peak cardiac index (or CO) provided the most consistent prognostic hemodynamic parameters during exercise. The best cut-offs for survival and cardiovascular events were mPAP/CO slope>3 Wood units (WU) and PAWP/CO slope>2 WU. A PAWP/CO slope cut-off>2 WU best differentiated pre- from post-capillary causes of PAP elevation during exercise. Upper limits of normal (defined as mean+2 sd) for the mPAP/CO and PAWP/CO slopes were strongly age-dependent and ranged in 30-to 70-year old healthy subjects from 1.6 to 3.3 WU and 0.6 to 1.8 WU, respectively.Increased mPAP/CO slope during exercise is associated with impaired survival and an independent, prognostically relevant cut-off>3 WU has been validated. A PAWP/CO slope>2 WU may be suitable for the differentiation between pre- and post-capillary causes of PAP increase during exercise.
The present study investigated whether children with a typical dyslexia profile and children with isolated spelling deficits show a distinct pattern of white matter alteration compared with typically developing peers. Relevant studies on the topic are scarce, rely on small samples, and often suffer from the limitations of conventional tensor‐based methods. The present Constrained Spherical Deconvolution study includes 27 children with typical reading and spelling skills, 21 children with dyslexia and 21 children with isolated spelling deficits. Group differences along major white matter tracts were quantified utilizing the Automated Fiber Quantification software and a lateralization index was calculated in order to investigate the structural asymmetry of the tracts. The two deficit groups mostly displayed different patterns of white matter alterations, located in the bilateral inferior longitudinal fasciculi, right superior longitudinal fasciculus, and cingulum for the group with dyslexia and in the left arcuate fasciculus for the group with isolated spelling deficits. The two deficit groups differed also with respect to structural asymmetry. Children with dyslexia did not show the typical leftward asymmetry of the arcuate fasciculus, whereas the group with isolated spelling deficits showed absent rightward asymmetry of the inferior fronto‐occipital fasciculus. This study adds evidence to the notion that different profiles of combined or isolated reading and spelling deficits are associated with different neural signatures.
An impairment in the visual attention span (VAS) has been suggested to hamper reading performance of individuals with dyslexia. It is not clear, however, if the very nature of the deficit is visual or verbal and, importantly, if it affects spelling skills as well. The current study investigated VAS by means of forced choice tasks with letters and symbols in a sample of third and fourth graders with age-adequate reading and spelling skills (n = 43), a typical dyslexia profile with combined reading and spelling deficits (n = 26) and isolated spelling deficits (n = 32). The task was devised to contain low phonological short-term memory load and to overcome the limitations of oral reports. Notably, eye-movements were monitored to control that children fixated the center of the display when stimuli were presented. Results yielded no main effect of group as well as no group-related interactions, thus showing that children with dyslexia and isolated spelling deficits did not manifest a VAS deficit for letters or symbols once certain methodological aspects were controlled for. The present results could not replicate previous evidence for the involvement of VAS in reading and dyslexia.
Findings on the neurophysiological correlates of developmental dyslexia are mixed, due to the differential conceptualization of the impairment. Studies differ on whether participants with developmental dyslexia are recruited based on reading skills only or reading as well as spelling skills. The current study contrasts the contribution of impaired reading and spelling to ERP correlates of print sensitivity, lexico-semantic access and sensitivity to orthographic regularities. Four groups of children were recruited: isolated reading deficit, isolated spelling deficit, combined reading and spelling deficit, and typically developing. Their neural correlates (EEG) of word, pseudohomophone, and pseudoword reading, as well as false font processing were compared. 1) All groups showed higher N1 amplitudes to letters than to false fonts. 2) Good spellers exhibited more negative N400 amplitudes for meaningless (pseudowords) than for meaningful stimuli (words and pseudohomophones). This effect was not observed in poor spellers. 3) Good readers showed sensitivity to orthographic regularities in a later time window (700-900 ms), whereas this was not the case for poor readers. 1) Print sensitivity is not affected by reading and/or spelling deficit in German-speaking 3rd graders. 2) Spelling deficits are associated with a reduced orthographic lexicon, 3) Reading deficits are associated with atypical use of sublexical information. As this effect was observed after lexico-semantic access, the results are discussed in terms of a possible orthographic reanalysis hypothesis.
Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) targets the respiratory and gastric epithelium, causing coronavirus disease 2019 . Tissue antigen expression variations influence host susceptibility to many infections. This study aimed to investigate the closely linked Lewis (FUT3) and ABO histo-blood types, including secretor (FUT2) status, to infections with SARS-CoV-2 and the corresponding severity of COVID-19.Study Design and Methods: Patients (Caucasians, n = 338) were genotyped for ABO, FUT3, and FUT2, and compared to a reference population of blood donors (n = 250,298). The association between blood types and severity of COVID-19 was addressed by dividing patients into four categories: hospitalized individuals in general wards, patients admitted to the intensive care unit with and without intubation, and deceased patients. Comorbidities were considered in subsequent analyses. Results: Patients with blood type Lewis (aÀbÀ) or O were significantly less likely to be hospitalized (odds ratio [OR] 0.669, confidence interval [CI] 0.446-0.971, OR 0.710, CI 0.556-0.900, respectively), while type AB was significantly more prevalent in the patient cohort (OR 1.519, CI 1.014-2.203). The proportions of secretors/nonsecretors, and Lewis a+ or Lewis b+ types were consistent between patients and controls. The analyzed blood groups were not associated with the clinical outcome as defined.Discussion: Blood types Lewis (aÀbÀ) and O were found to be protective factors, whereas the group AB is suggested to be a risk factor for COVID-19. The antigens investigated may not be prognostic for disease severity, but a role for ABO isoagglutinins in SARS-CoV-2 infections is strongly suggested.
Dyslexia in consistent orthographies like German is characterized by dysfluent reading, which is often assumed to result from failure to build up an orthographic lexicon and overreliance on decoding. However, earlier evidence indicates effects of lexical processing at least in some German dyslexic readers. We investigated variations in reading style in an eyetracking paradigm with German dysfluent 3rd and 4th graders. Twenty-six TypFix-readers (fixation counts within the range of 47 age-matched typical readers) were compared with 42 HighFix-readers (increased fixation counts). Both groups showed lexical access: Words were read more efficiently than nonwords and pseudohomophones. TypFix-readers showed stronger reliance on lexical reading than HighFix-readers (smaller length effects for number of fixations and total reading time, stronger lexicality effects for gaze duration, stronger word-pseudohomophone effects for mean saccade amplitude). We conclude that in both groups, sublexical and lexical reading processes were impaired due to inefficient visual-verbal integration.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.