Archive for August, 2006
An attempt to simulate letter-by-letter dyslexia in normal readers.
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An attempt to simulate letter-by-letter dyslexia in normal readers.
Brain Lang. 2006 Sep;98(3):251-63
Authors: Fiset S, Arguin M, Fiset D
We attempted to simulate the main features of letter-by-letter (LBL) dyslexia in normal readers through stimulus degradation (i.e. contrast reduction and removal of high spatial frequencies). The results showed the word length and the letter confusability effects characteristic of LBL dyslexia. However, the interaction of letter confusability and N size (i.e. a facilitatory effect only for low confusability targets) previously observed in LBL dyslexics [Arguin, M., Fiset, S., & Bub, D. (2002). Sequential and parallel letter processing in letter-by-letter reading. Cognitive Neuropsychology, 19, 535-555; Arguin, M., & Bub, D. (2006). Parallel processing blocked by letter similarity in letter dyslexia: a replication. Cognitive Neuropsychology, 22, 589-602; Fiset, D., Arguin, M. & McCabe, E. (2005a). The breakdown of parallel letter processing in letter-by-letter dyslexia. Cognitive Neuropsychology, 22, 1-22] was not found. Our results suggest that the type of visual degradation employed here may only partially correspond to the visual deficit present in LBL dyslexia and that this degradation may have prevented the normal readers from accessing visual information available to LBL dyslexics when they use the compensatory strategy of serial letter processing.
PMID: 16781767 [PubMed - indexed for MEDLINE]
(Source: Brain and Language)
Original post by Brain and Language
No commentsItalian developmental dyslexic and proficient readers: where are the differences?
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Italian developmental dyslexic and proficient readers: where are the differences?
Brain Lang. 2006 Sep;98(3):347-51
Authors: Barca L, Burani C, Di Filippo G, Zoccolotti P
Italian dyslexic children are characterized by a pervasive reading speed deficit, with relatively preserved accuracy. This pattern has been associated with predominant use of the nonlexical reading procedure. However, there is no evidence of a deficit in the lexical route of Italian dyslexics. We investigated both lexical and nonlexical reading procedures in dyslexic children through two marker effects, namely, the word frequency effect and the effect of contextual grapheme-to-phoneme conversion rules. Although dyslexics were slower and less accurate than controls, they were affected by word frequency, grapheme contextuality, and their interaction in a similar manner as average readers. These results show the use of lexical reading in Italian dyslexics, and refute the claim of a deficit in whole-word processing with consequent over-reliance on the nonlexical route.
PMID: 16815542 [PubMed - indexed for MEDLINE]
(Source: Brain and Language)
Original post by Brain and Language
No commentsBrain-behavior relations in reading and dyslexia: implications of chinese results.
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Brain-behavior relations in reading and dyslexia: implications of Chinese results.
Brain Lang. 2006 Sep;98(3):344-6
Authors: Perfetti CA, Tan LH, Siok WT
PMID: 16824590 [PubMed - indexed for MEDLINE]
(Source: Brain and Language)
Original post by Brain and Language
No commentsEfficiency of visual information processing in children at-risk for dyslexia: habituation of single-trial erps.
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Efficiency of visual information processing in children at-risk for dyslexia: habituation of single-trial ERPs.
Brain Lang. 2006 Sep;98(3):319-31
Authors: Regtvoort AG, van Leeuwen TH, Stoel RD, van der Leij A
To investigate underlying learning mechanisms in relation to the development of dyslexia, event-related potentials to visual standards were recorded in five-year-old pre-reading children at-risk for familial dyslexia (n=24) and their controls (n=14). At the end of second grade the children aged 8 years were regrouped into three groups according to literacy level and risk factor. Single-trial analyses revealed N1 habituation in the normal-reading controls, but not in the normal-reading at-risks, and a N1 amplitude increase in the group of poor-reading at-risks and poor-reading controls. No P3 habituation was found in either group. The normal-reading at-risk group exhibited the longest N1 and P3 latencies, possibly compensating for their reduced neuronal activity during initial information extraction. In contrast, the poor-reading group only showed prolonged P3, and their increase in (initial small) N1 amplitude together with normal N1 latencies, suggests inefficient processing in an early time window, which might explain automatisation difficulties in dyslexic readers.
PMID: 16870246 [PubMed - indexed for MEDLINE]
(Source: Brain and Language)
Original post by Brain and Language
No commentsConcerns over fetal ultrasound
Recent research published in the Proceedings of the National Academy of Sciences suggests that ultrasound could be damaging to developing brain of a fetus. Before we eschew ultrasound altogether, we should recognize that the study found that rat fetuses under repeated ultrasound had neurons that failed to connect properly to the cerebral cortex. That’s all. Don’t take our word for it, as Dr Pasko Rakic… “Our study in mice does not mean use of ultrasound on human fetuses for appropriate diagnostic and medical purposes should be abandoned,” said Dr. Pasko Rakic, lead researcher and chairman of the neurobiology department at Yale University School of Medicine. However, he said women should avoid unnecessary ultrasound scans until more research has been done. Dr. Joshua Copel, president-elect of the American Institute of Ultrasound Medicine, said his organization tries to discourage “entertainment” ultrasound, but considers sonograms important when there is a medical benefit. Rakic’s paper said that while the effects of ultrasound in human brain development are not known, there are disorders thought to be the result of misplacement of brain cells during their development. “These disorders range from mental retardation and childhood epilepsy to developmental dyslexia, autism spectrum disorders and schizophrenia,” the researchers said. But some expectant parents have sought scans to save as keepsakes even when they were not medically necessary, a practice the Food and Drug Administration discourages. But who would be so brash as to unnecessarily expose their child to ultrasound? We’ll give you three guesses… The Institute of Ultrasound Medicine was particularly concerned last year when it was announced Cruise had purchased an ultrasound machine so he and his pregnant fiancee, Katie Holmes, could do their own sonograms. Yep, we’ve covered this quagmire before. Twice, actually. More from the London Free Press… And press release from Yale…… (Source: Medgadget)
Original post by Medgadget
No commentsInvestigational Drug Targeting Inflammatory Bowel Disease Enters Second Human Clinical Trial
NovogenLimited’s investigational anti-inflammatory compound NV-52, is entering itssecond human clinical study following the successful completion oftoxicology testing. NV-52 is a novel compound developed by Novogen to target inflammatorybowel disease. This study was cleared to begin following the successful completion ofa Phase Ia study that confirmed the bio-availability of the drug in oralform, and its safety when administered at an acute dose. [click link for full article]
Original post by It’s My Life, People
No commentsA neurocognitive overview of reading acquisition and dyslexia across languages
Developmental Science Volume 9, Issue 5, Page 448-450, Sep 2006. (Source: Developmental Science)
Original post by Developmental Science
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