Clinical manifestations of developmental dyslexia (DD) are greatly variable, suggesting complex underlying mechanisms. It was recently advanced that the characteristics of DD in Italian, a language with shallow orthography, are influenced by a positive history for language delay.
We explored this hypothesis by studying in Italian individuals with DD (i) the brain representation of phonological processing with functional magnetic resonance imaging and (ii) the correlation between the patterns of activation and the presence/absence of previous language delay.
Thirteen individuals with DD and 13 controls participated in the functional magnetic resonance imaging experiment consisting of a rhyme-generation task.
Individuals with DD showed a reduced activation of phonological processing areas of the left hemisphere, such as the middle frontal gyrus, the precuneus, and the inferior parietal lobule, and in particular the superior temporal gyrus. Furthermore, patients with a history of language delay had reduced activation in the left inferior and medial frontal gyrus, that was associated with worse reading and phonological accuracy than patients with normal language development.
Neurofunctional profiles of Italian individuals with DD are correlated to the history of language delay, suggesting that the relatively better behavioral profiles observed in individuals without a history of language delay are associated with a major activation of frontal networks normally involved in phonological working memory.
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*IRCCS Stella Maris Foundation
†Division of Child Neurology and Psychiatry
‡Faculty of Medicine, University of Pisa, Pisa, Italy
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Supported by grants FIRB 2001 and PRIN 2007 from the Italian Ministry of University and Scientific Research and RC 2005 to 2007 of the Italian Ministry of Health.
Reprints: Michela Tosetti, PhD, IRCCS Stella Maris, Viale del Tirreno 331, 56018 Calambrone, Pisa, Italy (e-mail: firstname.lastname@example.org).
Received December 22, 2010
Accepted April 21, 2011