1,720,972 research outputs found
Brain plasticity in developmental dyslexia after phonological treatment: a beta EEG band study
No full textLinguistic EEG hemispheric reorganization was investigated in 14 dyslexic children after a 6-month phonological training (10 min/day through PC software). Error rates from three linguistic tasks significantly decreased and reading speed improved after the training. A significant positive correlation (r(12) = 0.536) was found at posterior sites for the phonological task only, showing that those children who had the greatest reading speed enhancement showed the largest left posterior EEG beta power increase
Sperimentazione di un training per il potenziamento della abilità fonologiche in bambini con sindrome di Down.
No full textIl lavoro descrive la sperimentazione di due programmi per il potenziamento delle abilità fonologiche con bambini con sindrome di Dow
Inverted EEG theta lateralization in dyslexic children during phonological processing
No full textThe phonological deficit hypothesis of dyslexia has been investigated in the present research by analysing language-related lateralization of the EEG theta band in a sample of dyslexic children. To this aim, a paradigm based on word-pair visual presentation was used in which the same words were processed in Semantic and Phonological tasks. Theta band amplitude, a cortical index that has been related to working memory processing, was analysed during four different phases of word elaboration, thus allowing to measure also the temporal dynamics of word reading/encoding in the verbal working memory. Control subjects showed a specific (and therefore efficient) task-related and time-dependent cortical activation: a peak of theta activity during word reading was found that decayed during the next inter stimulus interval. Furthermore, during word presentation in the Phonological task, theta amplitude was greater on the left hemisphere. Dyslexics evidenced an altered pattern of theta activation both in the temporal dimension and in the cortical space: their peak of activity was delayed to the first inter stimulus interval after word offset and was shifted to the right hemisphere throughout the whole epoch of Phonological task and in two phases of the Semantic task. Analysis of alpha band failed to replicate the complex pattern of lateralization found for theta band in the two groups, a result that suggests a specific functional role of theta band, which cannot be interpreted as a simple marker of cortical inhibition. Results point to a deficit, in dyslexic children, to recruit left hemisphere structures for the elaboration of the phonological component of the verbal working memory. This deficit was marked by a different, unspecific and dysfunctional hemispherical asymmetry of theta activation to language, a deficit that involved also the time course of phonological linguistic elaboration
Altered hemispheric asymmetry during word processing in dyslexic children: an event-related potential study
No full textThe present event-related potential study aimed at finding neurophysiological correlates of inadequate reading performances in developmental dyslexia. By using the same set of words in different linguistic tasks, we found variations of cortical asymmetry between dyslexic individuals and controls starting with the N420, a component supposed to index the phonological processing during reading. Whereas in controls this component was left lateralized, in disabled readers it was more distributed across hemispheres. The observed lack of lateralization in dyslexic individuals was also found in the later slow negative wave that developed in the 700 to 1500-ms time interval. We postulate that the altered asymmetry is related to an impairment of the grapheme-phoneme conversion mechanism. The findings would therefore support the hypothesis of a phonological deficit underlying this learning disability
Cortical reorganisation in dyslexic children after phonological training: evidence from early evoked potentials
No full textBrain plasticity was investigated in 14 Italian children affected by developmental dyslexia after 6 months of phonological training. The means used to measure language reorganization was the recognition potential, an early wave, also called N150, elicited by automatic word recognition. This component peaks over the left temporo-occipital cortex and its amplitude depends on linguistic expertise. N150 elicited by written words was measured both in dyslexic children before and after training and in a sample of matched normal readers during phonological, semantic and orthographic tasks. After training, dyslexic children increased their reading speed. Normal readers showed a typical left posterior N150, whereas in dyslexic children it was equally distributed across hemispheres before and shifted to left posterior sites after training. In addition, dyslexics' left posterior N150 asymmetry on the phonological task after training was significantly correlated with reading speed improvement, that is, those children who showed the greatest left shift in phonological N150 also had the greatest reading speed improvement. Source localization of the N150 component was made with both the Standard Low Resolution Electromagnetic Tomography software and the classical dipole analysis method termed Brain Electrical Source Analysis. The N150 generator lies in the left occipito-temporal cortex (Brodmann areas 39, 37 and 19) in good readers, but in right homologous areas in dyslexic children before training. After the treatment, the dyslexics' main N150 generator shifted to the left occipito-inferotemporal cortex (namely Brodmann areas 37 and 19) with small differences between tasks. The two source location methods provided consistent, converging solutions. Results add to the current literature on the phonological hypothesis of dyslexia by showing hemispheric reorganization of linguistic networks at the level of early word recognition potential. Furthermore, the present work is the first to investigate brain reorganization in a regular/transparent language like Italian
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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