ارتباط بین نارسایی مزمن و نارساخوانی در کودکان مبتلا به اختلالات یادگیری

Gestures and language are thought as two cognitive functions that are closely linked. From an evolutionary point of view, recent theories suggest that language evolved from manual gestures, rather than from animal vocal call. Moreover, in developmental psychology, several studies have revealed the role of gestures in the development of language abilities. In neuropsychology, the recent cognitive models of praxis processing have been mapped onto the cognitive models of written language processing, further suggesting an analogy between the way gestures and higher language abilities are processed. If gestures have a role in language development, a deficit in processing gestures should affect reading abilities. We report the case of five children (three with visuo-constructive disorders, two with dyslexia and one with both visuo-constructive disorder and dyslexia) who were tested using a series of tasks targetting reading and praxis abilities. Tasks assessing recognition, comprehension and production of gestures and language were included to evaluate the integrity of the lexical routes. Tasks to evaluate imitation of meaningless gestures and the ability to read pseudo-words were also included to investigate the sub-lexical routes. Results showed that children having visuo-constructive disorders were also affected by limb dyspraxia and dyslexia and that the language and praxis profiles based on the cognitive models were similar. In particular, the two children with visuo-constructive disorders showed a deficit at the lexical and sub-lexical routes for both gestures and language; the child with both dyslexia and visuo-constructive disorders had difficulties in the production of meaningful gestures and in meaningless actions imitation, as well as in reading words and pseudo-words. This pattern of results was compatible with a deficit at the level of the buffers as proposed by the two cognitive models. The two dyslexic children did not show any sign of limb dyspraxia, and their dyslexia was mainly attributed to a deficit to the lexical and sub-lexical route in one case; and to the sub-lexical route in the other case. Overall, results showed that those children with deficits in gesture processing also had difficulties in reading, but that children presenting only dyslexia did not show any sign of praxis impairments. Taken together, these findings are in line with the idea that gesture might play a role in the development of language abilities.