Found 10266 matches for
Cerebral venous thrombosis and portal vein thrombosis: a retrospective cohort study of 537,913 COVID-19 cases
Objectives: To estimate the absolute risk of cerebral venous thrombosis (CVT) and portal vein thrombosis (PVT) in the two weeks following a diagnosis of COVID-19, and to assess the relative risks (RR) compared to influenza or the administration of an mRNA vaccine against COVID-19. Design: Retrospective cohort study based on an electronic health records network Setting: Linked records between primary and secondary care centres within 59 healthcare organisations, primarily in the USA Participants: All patients with a confirmed diagnosis of COVID-19 between January 20, 2020 and March 25, 2021 were included (N=537,913, mean [SD] age: 46.2 [21.4] years; 54.9% females). Cohorts (matched for age, sex, and race) of participants diagnosed with influenza (N=392,424) or receiving the BNT162b2 or mRNA-1273 vaccine (N=366,869) were used for comparison. Main outcome measures: Diagnosis of CVT (ICD-10 code I67.6) or PVT (ICD-10 code I81) within 2 weeks after a diagnosis of COVID-19. Results: The incidence of CVT after COVID-19 diagnosis was 42.8 per million people (95% CI 28.5-64.2) including 35.3 per million (95% CI 22.6-55.2) first diagnoses. This was significantly higher than the CVT incidence in a matched cohort of patients with influenza (RR=3.83, 95% CI 1.56-9.41, P<0.001) and people who received an mRNA vaccine (RR=6.67, 95% CI 1.98-22.43, P<0.001). The incidence of PVT after COVID-19 diagnosis was 392.3 per million people (95% CI 342.8-448.9) including 175.0 per million (95% CI 143.0-214.1) first diagnoses. This was significantly higher than the PVT incidence in a matched cohort of patients with influenza (RR=1.39, 95% CI 1.06-1.83, P=0.02) and people who received an mRNA vaccine (RR=7.40, 95% CI 4.87-11.24, P<0.001). Mortality after CVT and PVT was 17.4% and 19.9% respectively. Conclusions: The incidence of CVT and PVT is significantly increased after COVID-19. The data highlight the risk of serious thrombotic events in COVID-19 and can help contextualize the risks and benefits of vaccination in this regard.
Adapting non-invasive human recordings along multiple task-axes shows unfolding of spontaneous and over-trained choice
Choices rely on a transformation of sensory inputs into motor responses. Using invasive single neuron recordings, the evolution of a choice process has been tracked by projecting population neural responses into state spaces. Here we develop an approach that allows us to recover similar trajectories on a millisecond timescale in non-invasive human recordings. We selectively suppress activity related to three task-axes, relevant and irrelevant sensory inputs and response direction in magnetoencephalography data acquired during context-dependent choices. Recordings from premotor cortex show a progression from processing sensory input to processing the response. In contrast to previous macaque recordings, information related to choice-irrelevant features is represented more weakly than choice-relevant sensory information. To test whether this mechanistic difference between species is caused by extensive overtraining common in non-human primate studies, we trained humans on >20,000 trials of the task. Choice-irrelevant features were still weaker than relevant features in premotor cortex after overtraining.
There is growing interest in interoception, the perception of the body’s internal state, and its relevance for health and higher-order cognition across development. To date, most evidence linking interoception to health and cognition has used the heartbeat counting task. However, the stability of the measure across time, particularly during childhood, and the etiological factors that underlie individual differences in stability remain largely unexamined. Using data from the ECHO twin sample (N=204 twin pairs), we estimated the magnitude of genetic and environmental influences on the stability of heartbeat counting across a two-year period (8-10 years), the longest time-frame examined. We found a relatively modest correlation between heartbeat counting accuracy across time (r=.35), with accuracy on the heartbeat counting task improving with age. In our longitudinal twin analysis, we found that the heritability of heartbeat counting dropped between Time 1 and Time 2 from 30% to 6%. No new genetic influences were observed at Time 2, suggesting that genetic influences across this age-range are entirely stable. In contrast, shared environmental influences increased from 6% to 22%, with most of the influence at Time 2 due to new environmental factors. Of note, nonshared environmental factors accounted for the greatest proportion of variance at both time points, 64% and 73% respectively, and were the main contributors to temporal stability in heartbeat counting accuracy. Future research should seek to identify these non-shared environmental factors and elucidate whether this relatively modest stability reflects variability of interoception across development or unreliability of the heartbeat counting task.
Effective psychological treatment for PTSD changes the dynamics of specific large-scale brain networks
AbstractVery little is known about the role of effective cognitive therapy in reversing imbalances in brain activity after trauma. We hypothesised that exaggerated threat perception characteristic of post-traumatic stress disorder (PTSD), and subsequent recovery from this disorder, are underpinned by changes in the dynamics of large-scale brain networks. Here, we use a novel data-driven approach with high temporal precision to find recurring brain networks from fMRI data and estimate when these networks become active during exposure to either trauma reminders or neutral pictures. We found that PTSD patients spend less time in two default mode sub-networks in contrast to trauma-exposed healthy controls, and that PTSD symptom severity correlates positively with time spent in the salience network during exposure to trauma reminders. The former are important for different aspects of self-referential processing and the latter for detection of threat. Importantly, the decreased time in the default mode sub-networks is rebalanced after successful cognitive therapy for PTSD. Our results show that remittance of PTSD through trauma-focused cognitive therapy is associated with the successful reinstatement of a healthy balance in self-referential and threat detection brain networks.
Efficient estimation of stereo thresholds: what slope should be assumed for the psychometric function?
Bayesian staircases are widely used in psychophysics to estimate detection thresholds. Simulations have revealed the importance of the parameters selected for the assumed subject’s psychometric function in enabling thresholds to be estimated with small bias and high precision. One important parameter is the slope of the psychometric function, or equivalently its spread. This is often held fixed, rather than estimated for individual subjects, because much larger numbers of trials are required to estimate the spread as well as the threshold. However, if this fixed value is wrong, the threshold estimate can be biased. Here we determine the optimal slope to minimize bias and maximize precision when measuring stereoacuity with Bayesian staircases. We performed 2- and 4AFC disparity detection stereo experiments in order to measure the spread of the disparity psychometric function in human observers assuming a Logistic function. We found a wide range, between 0.03 and 3.5 log10 arcsec, with little change with age. We then ran simulations to examine the optimal spread using the real data. From our simulations and for three different experiments, we recommend selecting assumed spread values between the percentiles 60-80% of the population distribution of spreads (these percentiles can be extended to other type of thresholds). For stereo thresholds, we recommend a spread σ=1.7 log10 arcsec for 2AFC (slope 𝛽 = 4.3/log10 arcsec), and σ=1.5 log10 arcsec for 4AFC (𝛽 = 4.9/log10 arcsec). Finally, we compared a Bayesian procedure (ZEST using the optimal σ) with five Bayesian procedures that are versions of ZEST-2D, Psi, and Psi-marginal. In general, our recommended procedure showed the lowest threshold bias and highest precision.
Aim: To explore which signs in visual functioning and visual behaviour in preschool children at risk for cerebral visual impairment (CVI) can potentially be early signs for a diagnosis at a later age.Methods: Thematic analysis of interviews with seven experts in the field of CVI and of a focus group with nine parents of five children with confirmed or suspected CVI.Results: Our experts and parents identified five likely early signs of CVI in preschool children with developmental impairments and brain injury who are at risk for CVI. They suggest that preschool children with CVI display atypical ways of coping with complex situations and of navigating their surroundings. Children also show impaired multisensory integration according to our interviewees. Furthermore, their visual responses often vary even when the stimulus remains the same or they might display impairments in visual recognition and identification.Interpretation: We have proposed five signs in visual functioning and visual behaviour in preschool children at risk for CVI that may be early signs for a diagnosis of CVI at a later age. This exploration can guide future retrospective and longitudinal research on diagnosing CVI at a young age. Early diagnosis and subsequent early intervention have a positive impact on learning and development of infants with disabilities.
Shortening the Leuven Perceptual Organisation Screening Test with Item Response Theory and Confirmatory Factor Analysis
The Leuven Perceptual Organisation Screening Test (L-POST) is a test for mid-level visual perceptual deficits after brain injury. Previous research demonstrated reliable test scores and valid test score interpretations. However, the test’s duration (20-35 minutes) is too long for a screening approach for all patients in clinic practice. Our aim was to shorten L-POST to 10-15 minutes based on statistical criteria of the items. Data from 3391 participants who completed L-POST was analysed. The test consists of 15 subtests with 5 items each. First, we demonstrated high internal consistency of the subtest items through Cronbach’s alpha and observed high correlations between scores based on all five items versus a selection of only two items per subtest. This showed that two items per subtest are sufficient. Next, Item Response Theory (IRT) was applied to guide the selection of the items. The highest correlation with full-scale subtest scores was observed when two items were selected for each subtest following an adaptive testing procedure. A pilot validation in a subsample of participants with low abilities demonstrated adaptive testing has reasonable sensitivity (79%) but limited specificity (54%) in classifying participants with impaired and unimpaired abilities. Last, we reduced the number of subtests through factor analysis. We showed that the subtests using Radial Frequency Patterns as stimuli were redundant and could be combined in one subtest. We conclude that L-POST can be shortened to 26 items (7-14 minutes) and an adaptive item selection procedure could prove particularly useful for screening purposes.
Visual Perceptual Deficit Screening in Stroke Survivors: Evaluation of Current Practice in the United Kingdom and Republic of Ireland
PURPOSEVisual perceptual deficits are frequently underdiagnosed in stroke survivors compared to sensory vision deficits or visual neglect. To better understand this imparity, we evaluated current practice for screening post-stroke visual perceptual deficits.METHODSWe conducted a survey targeted at stroke clinicians involved in screening visual perceptual deficits across the United Kingdom and Republic of Ireland.RESULTSForty orthoptists and 174 occupational therapists responded to the survey. Visual perceptual deficit screening was primarily conducted by occupational therapists (94%), with approximately 75-100% of stroke survivors screened per month. Respondents lacked consensus on whether several common post-stroke visual deficits were perceptual or not. During screening, respondents primarily relied on self-reports and observation (94%), while assessment batteries (58%) and screening tools were underutilised (56%) and selected inappropriately (66%). Respondents reported lack of training in visual perception screening (20%) and physical/cognitive condition of stroke survivors (19%) as extremely challenging during screening.CONCLUSIONSVisual perceptual deficits are screened post-stroke at a similar rate to sensory vision or visual neglect. Underdiagnosis of visual perceptual deficits may stem from both reliance on subjective and non-standardised screening approaches, and conflicting definitions of visual perception held among clinicians. We recommend increased training provision and brief performance-based screening tools.
Visual diagnostic tests must have a high degree of consistency in its measurements (high reliability) to ensure accurate assessment of perceptual abilities. The current study assessed test-retest reliability and practice effects in Leuven Perceptual Organisation Screening Test (L-POST) in 144 healthy volunteers using correlation analysis, Bland-Altman analysis, and multi-level modelling. Results from three analyses converged and supported an adequate reliability of L-POST. Additionally, multi-level modelling demonstrated an absence of practice effect, suggesting that the L-POST is suitable for repeat administration.
The Relationship Between Working Alliance and Symptom Improvement in Cognitive Therapy for Posttraumatic Stress Disorder.
Background: Working alliance has been shown to predict outcome of psychological treatments in multiple studies. Conversely, changes in outcome scores have also been found to predict working alliance ratings. Objective: To assess the temporal relationships between working alliance and outcome in 230 patients receiving trauma-focused cognitive behavioral treatment for posttraumatic stress disorder (PTSD). Methods: Ratings of working alliance were made by both the patient and therapist after sessions 1, 3, and 5 of a course of Cognitive Therapy for PTSD (CT-PTSD). Autoregressive, cross-lagged panel models were used to examine whether working alliance predicted PTSD symptom severity at the next assessment point and vice versa. Linear regressions tested the relationship between alliance and treatment outcome. Results: Both patients' and therapists' working alliance ratings after session 1 predicted PTSD symptom scores at the end of treatment, controlling for baseline scores. At each assessment point, higher therapist working alliance was associated with lower PTSD symptoms. Crossed-lagged associations were found for therapist-rated alliance, but not for patient-rated alliance: higher therapists' alliance ratings predicted lower PTSD symptom scores at the next assessment point. Similarly, lower PTSD symptoms predicted higher therapist working alliance ratings at the next assessment point. Ruminative thinking was negatively related to therapists' alliance ratings. Conclusions: Working alliance at the start of treatment predicted treatment outcome in patients receiving CT-PTSD and may be an important factor in setting the necessary conditions for effective treatment. For therapists, there was a reciprocal relationship between working alliance and PTSD symptom change in their patients during treatment, suggesting that their alliance ratings predicted symptom change, but were also influenced by patients' symptom change.
Several scientific, engineering, and medical advancements are based on breakthroughs made by people who excel in mathematics. Our current understanding of the underlying brain networks stems primarily from anatomical and functional investigations, but our knowledge of how neurotransmitters subserve numerical skills, the building block of mathematics, is scarce. Using 1H magnetic resonance spectroscopy (N=54, 3T, semi-LASER sequence, TE=32ms, TR=3.5s), the study examined the relation between numerical skills and the brain’s major inhibitory (GABA) and excitatory (glutamate) neurotransmitters. A negative association was found between the performance in a number sequences task and the resting concentration of GABA within the left intraparietal sulcus (IPS), a key region supporting numeracy. The relation between GABA in the IPS and number sequences was specific (i) to parietal but not frontal regions and (ii), and to GABA but not glutamate. It was additionally found that the resting functional connectivity of left IPS and left superior frontal gyrus is positively associated with number sequences performance. However, resting GABA concentration within the IPS explained number sequences performance above and beyond the resting frontoparietal connectivity measure. Our findings further motivate the study of inhibition mechanisms in the human brain and significantly contribute to our current understanding of numerical cognition's biological bases.
Intended for use with the Guideline, this book combines the best available research with expert clinical recommendations, to help readers make the clinical decisions that are best for their patients.
Der Ratgeber beschreibt, wie sich die seelischen Folgen eines Traumas äußern, und geht dabei vor allem auf die Merkmale der Posttraumatischen Belastungsstörung ein.
This is a critical resource for clinicians in interpreting somatic symptoms and co-occurring medical disorders.
This is a critical resource for clinicians in interpreting somatic symptoms and co-occurring medical disorders.
since baseline levels of anxiety and arousal strongly predict the levels reached during panic challenges, expectancy effects could play a very significant role in the outcome of panic induction studies reports preliminary findings of two experiments [with panic disorder patients] investigating this hypothesis by manipulating expectancy effects directly via instructions our results show strong and consistent effects of a simple expectancy manipulation on subsequent responses to HV [hyperventilation] stress in panic patients and normal controls
New to This Edition *Incorporates major advances in research and clinical practice. *Chapters on additional evidence-based individual treatments: prolonged exposure therapy, cognitive therapy, cognitive processing therapy, brief eclectic ...