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People with dyslexia often struggle with the ability to accurately decode and identifywhat they read. Although disrupted processing of speech sounds hasbeen implicated in the underlying pathology of dyslexia, the basisof this disruption and how it interferes with reading comprehensionhas not been fully explained. Now, new research published by CellPress in the December 22 issue of the journal Neuron finds that aspecific abnormality in the processing of auditory signals accountsfor the main symptoms of dyslexia. "It is widely agreed that for a majority of dyslexic children, themain cause is related to a deficit in the processing of speechsounds," explains senior study author, Dr. Anne-Lise Giraud andFranck Ramus from the Ecole Normale Sup rieure in Paris, France."It is also well established that there are three main symptoms ofthis deficit: difficulty paying attention to individual speechsounds, a limited ability to repeat a list of pseudowords ornumbers, and a slow performance when asked to name a series ofpictures, colors, or numbers as quickly as possible. However, theunderlying basis of these symptoms has not been elucidated." Dr. Giraud and colleagues examined whether an abnormality in theearly steps of auditory processing in the brain, called "sampling,"is linked with dyslexia by focusing on the idea that an anomaly inthe initial processing of phonemes, the smallest units of soundthat can be used to make a word, might have a direct impact on theprocessing of speech. The researchers found that typical brain processing of auditoryrhythms associated with phonemes was disrupted in the left auditorycortex of dyslexics and that this deficit correlated with measuresof speech sound processing. Further, dyslexics exhibited anenhanced response to high-frequency rhythms that indirectlyinterfered with verbal memory. It is possible that this"oversampling" might result in a distortion of the representationof speech sounds. "Our results suggest that the left auditory cortex of dyslexicpeople may be less responsive to modulations at very specificfrequencies that are optimal for analysis of speech sounds andoverly responsive to higher frequencies, which is potentiallydetrimental to their verbal short-term memory abilities," concludesDr. Giraud. "Taken together, our data suggest that the auditorycortex of dyslexic individuals is less fine-tuned to the specificneeds of speech processing." Additional References Citations. The e-commerce company in China offers quality products such as Led Commercial Lighting Fixtures Manufacturer , Led Torch Flashlight Manufacturer, and more. For more , please visit Industrial Lighting Fixture today!
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