1,721,640 research outputs found
Modelli per l'analisi dei dati nelle scienze sociali
No full textQuesto testo presenta un'ampia gamma di modelli statistici utili all'analisi dei dati comunemente incontrati nelle scienze sociali e psicologiche. Il testo presenta il modello lineare generale come base delle tecniche statistiche trattate, che spaziano dalla correlazione, regressione, ANOVA, analisi fattoriale, equazioni strutturali, arrivando a coprire tematiche attuali come la moderazione e la mediazione, i modelli misti, i modelli generalizzati. Basandosi su un modello unico declinato nelle varie situazioni di analisi dei dati, il testo presenta le varie tecniche statistiche concentrandosi sull'utilizzo pratico e sull'interpretazione dei risultati delle statistiche presentate. Vari riferimenti ai software più comuni (SPSS, SAS, R) sono spesso presenti, sebbene il libro sia fruibile indipendentemente dal software preferito dal lettore. A corredo sono stati introdotti alcuni inserti più avanzati: paragrafi aggiuntivi opportunamente segnalati e box integrativi, rivolti ai lettori più esperti, come studenti di dottorato dei primi anni, tesisti alle prese con tesi empiriche e ricercatori interessati
THE ROLE OF NEURORADIOLOGY ON THE HEADACHES IN CHILDREN
No full textTHE ROLE OF NEURORADIOLOGY ON THE HEADACHES IN CHILDREN
IL RUOLO DELLA NEURORADIOLOGIA NELLE CEFALEE DELL’ETA’ EVOLUTIVA
E.Tozzi, M.Gallucci
Clinica Pediatrica, UO di Neuroradiologia
Università degli studi L’Aquila
[email protected]
Several Authors studied correlation between the neuroimaging and the headaches. The studies has been used as in order to give the comprehension pathogenetical mechanisms of migraine, as to give informations to physician and neurologist. Concerning the diagnostics of headache, an EFNS Task Force evaluated recently the usefulness of imaging procedures in non-acute headache patients on the basis of evidence from the literature and defined guidelines on when to use magnetic resonance imaging or computed tomography.[1,3]
MR techniques has been used: Bold-f MRI (blood oxygen level dependent functional MRI,), MR spectroscopy, Diffuse-weighted and perfusion weighted MRI. Until now the number of studies has been too small to establish an optimal protocol. There are no studies concerning the repeatability of functional MR technique and there are no studies correlating results with those obtained from electrophysiological techniques. Bold – f MRI signal ,marker of neuronal activation, explored the visual cortex in migraine with aura. Magnetic resonance spectroscopy studies are compatible with an abnormal energy metabolism and abnormal magnesium concentrations. Diffusion weighted MRI studies found abnormalities of white matter which were mild compared with other diseases.
The first PET study scanned during spontaneous migraine attacks, revealed brainstem activation. Voxel-based morphometry showed in cluster headache a significant unilateral increase of grey matter in the posterior and inferior hypotalamus and in the pain matrix in TTH.[3]
Appropriate selection of patients with headache for neuroimaging to look for secondary causes is very important. Red flags act as screening tools to help in identifying those patients presenting with headache who would benefit from prompt neuroimaging, and may increase the yield. Three red flag features proved to be statistically significant with the p-value of less than 0.05 on both univariate and multivariate analysis. These were: paralysis; papilloedema; and "drowsiness, confusion, memory impairment and loss of consciousness". The changing pattern of headache, fluctuating between tension headache, migraine, and non-specific symptoms should lower the threshold for neuroimaging. Investigations of adult patients with chronic headache and normal physical examination have shown that atypical headaches are associated with increased risk of finding MRI abnormalities (14.1%) compared to those with migraine (0.6%) or tension headache (1.4%). [2]
Abnormal neurological examen is the sign more important and more predictable to brain lesion in headache
Spatial-numerical consistency impacts on preschoolers' numerical representation: Children can count on both peripersonal and personal space
No full textAlthough the existence of an association between numbers and space has been largely documented in educated adults, the origin of this association still remains debated. Recent evidence suggests that associations between numbers and space might originate during the preschool years from the repeated action of counting in peripersonal space. However, it is also possible that preschoolers may additionally acquire directional preferences by counting on their own body, specifically on their fingers. To address this hypothesis, the present study explores the presence of early directional indexes in processing numerical information in both peripersonal and personal space in a sample of 90 preschoolers. We identified children who consistently exhibited a counting directional bias and generalized it to their processing of numbers in space. Moreover, given the tight connection between counting routine and numerical knowledge, we investigated the relation between these indexes and numerical achievement, evaluated by means of various tasks. Results indicate that distinct spatial-numerical associations, in both peripersonal and personal space, coexist from an early age and can be used flexibly. However, regardless of its directionality, the presence of a consistent spatial-numerical association appears to be related to numerical comprehension
320-row detector dynamic 4D-CTA for the assessment of brain and spinal cord vascular shunting malformations: A technical note
No full textShunting vascular malformations of the brain and spinal cord are traditionally studied using digital subtraction angiography (DSA), the current gold standard imaging method routinely used because of its favourable combination in terms of spatial and temporal resolution. Because DSA is relatively expensive, time-consuming and carries a risk of silent embolic events and a small risk of transient or permanent neurologic deterioration, a non-invasive alternative angiographic method is of interest. New 320 row-detector CT scanners allow volumetric imaging of the whole brain with temporal resolution up to ≅ 3 Hz. Those characteristics make computed tomography angiography (CTA) an affordable imaging method to study the haemodynamics of the whole brain and can also be applied to the study of limited portions of the spinal cord. The aim of this paper is to make a brief summary of our experience in studying shunting vascular malformation of the brain and spinal cord using dynamic 4D-CTA, explaining the technical details of the studies performed at our institution, and the state-of-the-art major advantages and drawbacks of this new technique. We found that dynamic 4D-CTA is able to depict the main architectural characteristics of previously untreated vascular shunting malformations both in brain and spinal cord (i.e. their main arterial feeders and draining veins) allowing their correct diagnosis and exhaustive classification, limiting the use of DSA for therapeutic purposes
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