Dyslexia, Language and the Brain: A Research Proposal
Maria Scappini
University of Verona
maria.scappini@univr.it
Recent studies have shown that dyslexic children’s impairment is not restricted to
their well-known reading and spelling difficulties. A series of studies on language
comprehension in children with developmental dyslexia (DD) shows that they
experience significant difficulties in grasping the meaning of certain types of
sentences, such as relative clauses, passive sentences, sentences with imperfective
verbs, sentences with ‘so-called’ scalar terms (such as or and some), negative
sentences, and sentences with pronouns. In addition, children with DD perform
significantly worse than controls in grammaticality judgment tasks involving
morphosyntactic agreement violations, function words, and anomalous word
order. Notably, these difficulties are found in the domain of spoken language
comprehension, therefore they cannot be a secondary outcome of the reading
difficulties. Implicit learning has been reported to be impaired as well, as shown by
the poor performance obtained by dyslexic children in artificial grammar tasks.
At the neuro-anatomical level, a large body of evidence has uncovered significant
volumetric differences between subjects with DD and unimpaired controls in several
brain areas. In particular, a review of the relevant studies shows that three regions
consistently differ in dyslexic subjects: the inferior frontal gyrus (bilaterally), the
superior temporal and the left temporo-parieteal cortex, and the cerebellum.
Moreover, some of these studies show that the volumetric abnormalities of dyslexic
subjects are significant predictors of the reading, spelling, and working memory
difficulties typically associated with DD. However, no volumetric study has tested the
correlation between brain volume and receptive language skills in DD.
The present study aims at: (a) Comparing the volume of specific brain
areas (viz. inferior frontal gyrus, superior temporal and temporo-parietal cortex, and
cerebellum) of children/adolescents with DD to that of children/adolescents without
DD; (b) Testing the correlation between measures of language comprehension and
measures of working memory and implicit learning ability.
In addition, a test on the production of clitics will be carried out to ensure that the
subjects involved in the study do not suffer from Specific Language Impairment as
well.