Phonological processing in students with developmental dyslexia, ADHD and intellectual disability

ABSTRACT Purpose: to compare the performance of students with dyslexia, intellectual disability and ADHD on the skills of phonological awareness, phonological access to the mental lexicon, and phonological working memory. Methods: this is a descriptive, cross sectional and quantitative study. The sample was composed of 32 students, divided into the following groups: G1 - students with dyslexia; G2 - students with ADHD; G3 - students with intellectual disability. The children were assessed on their skills of phonological awareness, phonological working memory, and phonological access to the mental lexicon. A descriptive and inferential analysis was made, using the non-parametric Kruskal-Wallis test. Results: statistically significant differences were observed among the three groups on the phonological working memory skills for pseudowords, forward digit repetition, and backward digit repetition; phonological awareness on syllable level, phoneme level, test total score, and digits subtest of the rapid automatized naming test. Through the descriptive analysis, it was observed that G1 had the best results on all the skills assessed, followed by G2 and G3 Conclusion: differences were found on the skills of phonological working memory and phonological awareness among the groups of students presented with dyslexia, ADHD and intellectual disability.

The Left Posterior Superior Temporal Gyrus Participates Specifically in Accessing Lexical Phonology

Impairments in phonological processing have been associated with damage to the region of the left posterior superior temporal gyrus (pSTG), but the extent to which this area supports phonological processing, independent of semantic processing, is less clear. We used repetition priming and neural repetition suppression during functional magnetic resonance imaging (fMRI) in an auditory pseudoword repetition task as a semantics-free model of lexical (whole-word) phonological access. Across six repetitions, we observed repetition priming in terms of decreased reaction time and repetition suppression in terms of reduced neural activity. An additional analysis aimed at sublexical phonology did not show significant effects in the areas where repetition suppression was observed. To test if these areas were relevant to real word production, we performed a conjunction analysis with data from a separate fMRI experiment which manipulated word frequency (a putative index of lexical phonological access) in picture naming. The left pSTG demonstrated significant effects independently in both experiments, suggesting that this area participates specifically in accessing lexical phonology.