Acceso usuarios
México
In the present study, we propose to explore the Event-Related Potentials components elicited in reading disabled (RD) and normal readers (NR) children by phonological and semantic processes using an auditory sentence comprehension task, that manipulate both phonological and semantic expectancies. Reading deficiencies in both these processes have been demonstrated in RD children, thus similar problems might also be expected for oral language in these children. Twenty-two male children (9-12 years old) with normal IQ, were classified by Neuropsychological Battery for Reading Disabilities into two groups: Normal Readers (NR, n=11) and Reading Disabled (RD, n=11). ERPs were recorded from 19 derivations of the I.S. 10-20. Children were presented with spoken sentences that ended with a word that was either (a) semantically congruent, and phonologically expected, (b) semantically incongruent, but beginning with the same initial phonemes as the congruent completion, or (c) semantically incongruent, and phonologically unexpected. For each type of sentence, ERP were analyzed in two time windows: early time window (330-430 ms) related to phonological processing, as well as a later N400 window (515-615 ms) that would reflect the semantic processing. In both groups, the three types of sentences elicited a negative waveform with an onset at 200 ms that lasted until approximately 900 ms. This negative waveform had greater amplitude in response to semantically incongruent, compared to semantically congruent sentences. Results revealed a probably anomalous phonological processing in RD children, reflected by a greater ERP response to expected, than to unexpected, words in a given sentential context. However, both the N400 responses related to semantic processing, and the behavioral responses related to the correctness of sentences, were comparable between RD and NR children.
