1,262 research outputs found
Transfusion trigger in critically ill patients: has the puzzle been completed?
In stable critically ill children, the adoption of a restrictive transfusion strategy based on a predefined hemoglobin threshold of 7 g/dl significantly decreased transfusion requirements without affecting outcome. These results strengthen previous observations made in volume resuscitated adults when a similar blood transfusion strategy was used. It also indirectly corroborates studies reporting the beneficial effects of leukoreduction of red blood cell (RBC) transfusion units on patient outcome. This study indicated that the maintenance of a higher hemoglobin concentration with RBC transfusion in an attempt to increase tissue oxygen delivery is not associated with a clinical benefit. This may be related to the storage process, which could affect the ability of RBCs to transport and deliver oxygen to the tissues. This point, however, remains controversial. It should also be remembered that increasing hemoglobin concentration will not always result in a greater oxygen delivery, as transfusion related increased blood viscosity could be associated with a reduction in blood flow. Further research should compare a symptomatic transfusion strategy to a hemoglobin-based strategy on the outcome of high risk patients
Impulsivity and Intrusive Thoughts: Related Manifestations of Self-Control Difficulties?
Impulsive behaviors and intrusive thoughts are prominent in psychopathology. Two studies were conducted to explore their relationships. In Study 1, 250 participants completed the UPPS Impulsive Behavior Scale and the Thought Control Ability Questionnaire (TCAQ). In Study 2 involving a sample of 97 female students, the relations between impulsivity and different types of thought control difficulties were examined. Both negative urgency and lack of perseverance were significantly related to the tendency to experience intrusive thoughts as measured by the TCAQ, the Penn State Worry Questionnaire, the obsessing subscale of the Obsessive-Compulsive Inventory-Revised, and an intrusion subscale of the White Bear Suppression Inventory. Regression analyses revealed that negative urgency and lack of perseverance independently contributed to worries and thought control difficulties and that negative urgency was the strongest predictor of all types of intrusions. On the basis of these findings, the authors discuss cognitive processes and content that may be related the different facets of impulsivit
The relationships between episodic memory, working memory, and executive functions: The contribution of the prefrontal cortex
Discusses the neurophysiological functions of the prefrontal cortex related to memory processes. Functional brain imaging studies have revealed that distinct regions of the prefrontal cortex are engaged in episodic memory operations, with some regions apparently part of multiple networks subserving different memory abilities. The prefrontal cortex is also involved in shifting processes. Working memory processes within the dorsolateral and ventrolateral frontal cortex are organized according to the type of processing required rather than the nature of the information being processed. The binding of contextual information, both incidentally and intentionally, is the most crucial process involved in episodic memory. Inhibition control involves not only bilateral prefrontal areas, but also posterior regions and subcortical structures, but the specific role of the cerebral areas is not clear at present
How Inhibition Relates to Impulsivity after Moderate to Severe Traumatic Brain Injury
Impulsive behaviors and poor inhibition performances are frequently described in patients with traumatic brain injury (TBI). However, few studies have examined impulsivity and associated inhibition impairments in these patients. Twenty-eight patients with moderate to severe TBI and 27 matched controls performed a stop-signal task designed to assess prepotent response inhibition (the ability to inhibit a dominant or automatic motor response) in a neutral or emotional context and a recent negative task to assess resistance to proactive interference (the ability to resist the intrusion into memory of information that was previously relevant but has since become irrelevant). Informants of each patient completed a short questionnaire designed to assess impulsivity. Patients showed a significant increase in current urgency, lack of premeditation, and lack of perseverance when retrospectively compared with the preinjury condition. Group comparisons revealed poorer prepotent response inhibition and resistance to proactive interference performances in patients with TBI. Finally, correlation analyses revealed a significant positive correlation between urgency (the tendency to act rashly when distressed) and prepotent response inhibition in patients with TBI. This study sheds new light on the construct of impulsivity after a TBI, its related cognitive mechanisms, and its potential role in problematic behaviors described after a TBI. (JINS, 2013, 19, 1-9
Revisiting the Past: Replicability of a Historic Long-Term Vegetation Dynamics Assessment in the Era of Big Data Analytics
Open and analysis-ready data, as well as methodological and technical advancements have resulted in an unprecedented capability for observing the Earth’s land surfaces. Over 10 years ago, Landsat time series analyses were inevitably limited to a few expensive images from carefully selected acquisition dates. Yet, such a static selection may have introduced uncertainties when spatial or inter-annual variability in seasonal vegetation growth were large. As seminal pre-open-data-era papers are still heavily cited, variations of their workflows are still widely used, too. Thus, here we quantitatively assessed the level of agreement between an approach using carefully selected images and a state-of-the-art analysis that uses all available images. We reproduced a representative case study from the year 2003 that for the first time used annual Landsat time series to assess long-term vegetation dynamics in a semi-arid Mediterranean ecosystem in Crete, Greece. We replicated this assessment using all available data paired with a time series method based on land surface phenology metrics. Results differed fundamentally because the volatile timing of statically selected images relative to the phenological cycle introduced systematic uncertainty. We further applied lessons learned to arrive at a more nuanced and information-enriched vegetation dynamics description by decomposing vegetation cover into woody and herbaceous components, followed by a syndrome-based classification of change and trend parameters. This allowed for a more reliable interpretation of vegetation changes and even permitted us to disentangle certain land-use change processes with opposite trajectories in the vegetation components that were not observable when solely analyzing total vegetation cover. The long-term budget of net cover change revealed that vegetation cover of both components has increased at large and that this process was mainly driven by gradual processes. We conclude that study designs based on static image selection strategies should be critically evaluated in the light of current data availability, analytical capabilities, and with regards to the ecosystem under investigation. We recommend using all available data and taking advantage of phenology-based approaches that remove the selection bias and hence reduce uncertainties in results.Peer Reviewe
A Measure of Dysfunctional Eating-Related Cognitions in People with Psychotic Disorders
Obesity and binge eating disorder are common in individuals with psychotic disorders. Eating and weight-related cognitions are known to influence eating behaviors. The study was designed to assess the psychometric properties of the Mizes Anorectic Cognitions Questionnaire (MAC-R) in patients with psychotic disorders. Binge eating disorder (BED), body mass index (BMI), the MAC-R and the three factor eating questionnaire (TFEQ) were assessed in 125 patients with a diagnosis of schizophrenia or schizoaffective disorder. Whereas the MAC-R has not acceptable psychometric properties, a brief version of the MAC-R (BMAC) has good psychometrical properties and is correlated with TFEQ and BMI. Binge eating disorder is also correlated to the Rigid Weight Regulation and Fear of Weight Gain subscale. The BMAC is a useful brief measure to assess eating and weight related cognitions in people with psychotic disorder
A Multidimensional Approach to Apathy after Traumatic Brain Injury
Apathy is commonly described following traumatic brain injury (TBI) and is associated with serious consequences, notably for patients' participation in rehabilitation, family life and later social reintegration. There is strong evidence in the literature of the multidimensional nature of apathy (behavioural, cognitive and emotional), but the processes underlying each dimension are still unclear. The purpose of this article is first, to provide a critical review of the current definitions and instruments used to measure apathy in neurological and psychiatric disorders, and second, to review the prevalence, characteristics, neuroanatomical correlates, relationships with other neurobehavioural disorders and mechanisms of apathy in the TBI population. In this context, we propose a new multidimensional framework that takes into account the various mechanisms at play in the facets of apathy, including not only cognitive factors, especially executive, but also affective factors (e.g., negative mood), motivational variables (e.g., anticipatory pleasure) and aspects related to personal identity (e.g., self-esteem). Future investigations that consider these various factors will help improve the understanding of apathy. This theoretical framework opens up relevant prospects for better clinical assessment and rehabilitation of these frequently described motivational disorders in patients with brain injur
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