Search results for " function"
showing 10 items of 9395 documents
Asymmetry in dopamine D2/3 receptors of caudate nucleus is lost with age
2007
Molecular and functional imaging techniques reveal evidence for lateralization of human cerebral function. Based on animal data, we hypothesized that asymmetry in dopamine neurotransmission declines during normal aging. In order to test this hypothesis, we measured dopamine D2/3 receptor availability with [18F]desmethoxyfallypride-PET (DMFP) in putamen and caudate nucleus (NC) of 21 healthy, right-handed males (24-60 years; 35+/-10). For volumetric analysis, high-resolution T1-weighted MR-images were obtained in 18 of the PET-subjects in order to assess possible age-related decreases in NC and putamen volume. The calculated DMFP binding potentials (BP) showed a right-ward asymmetry in NC of…
Age slowing down in detection and visual discrimination under varying presentation times
2017
[EN] The reaction time has been described as a measure of perception, decision making, and other cognitive processes. The aim of this work is to examine agerelated changes in executive functions in terms of demand load under varying presentation times. Two tasks were employed where a signal detection and a discrimination task were performed by young and older university students. Furthermore, a characterization of the response time distribution by an exGaussian fit was carried out. The results indicated that the older participants were slower than the younger ones in signal detection and discrimination. Moreover, the differences between both processes for the older participants were higher,…
Cognitive reserve and cognitive performance of patients with focal frontal lesions.
2016
The Cognitive reserve (CR) hypothesis was put forward to account for the variability in cognitive performance of patients with similar degrees of brain pathology. Compensatory neural activity within the frontal lobes has often been associated with CR. For the first time we investigated the independent effects of two CR proxies, education and NART IQ, on measures of executive function, fluid intelligence, speed of information processing, verbal short term memory (vSTM), naming, and perception in a sample of 86 patients with focal, unilateral frontal lesions and 142 healthy controls. We fitted multiple linear regression models for each of the cognitive measures and found that only NART IQ pre…
A Bayesian Method for Predicting 5‐Fluorouracil Pharmacokinetic Parameters Following Short‐Term Infusion in Patients With Colorectal Cancer
2003
Abstract The objective of this study was to develop a population pharmacokinetic model and validate it using a Bayesian approach for predicting, a priori and a posteriori , the individual volume of distribution ( V d ) and clearance ( Cl ) of 5‐fluorouracil (5‐FU) given as short‐term intravenous infusion in weekly and multiple doses. Forty‐four patients were divided in group A (5‐FU weekly doses) including 27 patients with nonmetastatic colorectal adenocarcinoma treated with 450 mg/m 2 of 5‐FU, 1 day per week for 48 doses, plus oral levamisol (50 mg/8 h) for 3 days, every 15 days and group B (5‐FU multiple doses) including 17 patients with metastatic colorectal adenocarcinoma, receiving 5‐F…
Difficulties of Drivers With Dyslexia When Reading Traffic Signs: Analysis of Reading, Eye Gazes, and Driving Performance
2018
A group of adult individuals with dyslexia and a matched group of normally reading individuals participated in a driving simulation experiment. Participants were asked to read the word presented on every direction traffic sign encountered along a route, as far as possible from the sign, maintaining driving performance. Word frequency and word length were manipulated as within-subject factors. We analyzed (a) reading accuracy, (b) how far the sign was when the participant started to give the response, (c) where the participant looked during the time leading up to the response, and (d) the variability of the vehicle’s speed during that time and during driving on similar segments of the route…
Absence of cardiovascular autonomic dysfunction and vagal pancreatic impairment in idiopathic achalasia of the oesophagus
2007
Abstract Extra-oesophageal autonomic dysfunction in idiopathic achalasia is not well documented, due to contradictory results reported. We aimed to study the cardiovascular and pancreatic autonomic function in patients with idiopathic achalasia. Thirty patients with idiopathic achalasia (16M/14F; 34.5 ± 10.8 years) and 30 healthy volunteers (13M/17F; 34.8 ± 10.7 years) were prospectively studied. Age >60 years and conditions affecting results of autonomic evaluation were excluded. Both groups underwent the sham feeding test and plasmatic levels of pancreatic polypeptide (PP) were determined by radioimmunoassay (basal, at 5, 10, 20 and 30 min). Cardiovascular parasympathetic (deep breathing…
The grey matter correlates of impaired decision-making in multiple sclerosis.
2014
Objective: People with multiple sclerosis (MS) have difficulties with decision-making but it is unclear if this is due to changes in impulsivity, risk taking, deliberation or risk adjustment, and how this relates to brain pathology. \ud \ud Methods: We assessed these aspects of decision-making in 105 people with MS and 43 healthy controls. We used a novel diffusion MRI method, diffusion orientational complexity (DOC), as an index of grey matter pathology in regions associated with decision-making and also measured grey matter tissue volumes and white matter lesion volumes. \ud \ud Results: People with MS showed less adjustment to risk and slower decision-making than controls. Moreover, impa…
The effect of adjustable dosing with budesonide/formoterol on health-related quality of life and asthma control compared with fixed dosing
2004
Budesonide/formoterol in a single inhaler is an effective therapy for asthma. We investigated whether adjustable maintenance dosing with budesonide/formoterol could maintain health-related quality of life (HRQL) and asthma control.Asthma patients (n = 4025) received budesonide/formoterol (Symbicort 160/4.5 microg) 2 inhalations twice daily (b.i.d.) for 4 weeks during run-in of this open, multicentre study. Patients were randomised to adjustable dosing (budesonide/formoterol 1 inhalation b.i.d.; stepping up to 2 or 4 inhalations bid for 1 week if asthma worsened) or fixed dosing (budesonide/formoterol 2 inhalations b.i.d.), for 12 weeks. Change in HRQL (standardised Asthma Quality of Life Qu…
Differential impact of continuous theta-burst stimulation over left and right DLPFC on planning
2011
Most neuroimaging studies on planning report bilateral activations of the dorsolateral prefron- tal cortex (dlPFC). Recently, these concurrent activations of left and right dlPFC have been shown to dou- ble dissociate with different cognitive demands imposed by the planning task: Higher demands on the extraction of task-relevant information led to stronger activation in left dlPFC, whereas higher demands on the integration of interdependent information into a coherent action sequence entailed stronger activa- tion of right dlPFC. Here, we used continuous theta-burst stimulation (cTBS) to investigate the supposed causal structure-function mapping underlying this double dissociation. Two grou…
Serial echocardiographic left ventricular ejection fraction measurements: A tool for detecting thalassemia major patients at risk of cardiac death
2013
Cardiac damage remains a major cause of mortality among patients with thalassemia major. The detection of a lower cardiac magnetic resonance T2* (CMR-T2*) signal has been suggested as a powerful predictor of the subsequent development of heart failure. However, the lack of worldwide availability of CMR-T2* facilities prevents its widespread use for follow-up evaluations of cardiac function in thalassemia major patients, warranting the need to assess the utility of other possible procedures. In this setting, the determination of left ventricular ejection fraction (LVEF) offers an accurate and reproducible method for heart function evaluation. These findings suggest a reduction in LVEF≥7%, ov…