Processamentos linguístico, perceptivo auditivo e executivo em crianças : o papel da idade, do tipo de escola e do TDAH

Abstract

The main goal of the present thesis was to explore the development and relationship between language and executive functions (EF), a topic of extreme relevance both for research and clinical practice. Given the scarcity of studies of the association between language and executive abilities in typically developing children, there is an absence of assessment instruments with norms for children of different ages and education levels. Verbal fluency (VF) tasks are some of the most commonly used tools in the neuropsychological assessment of linguistic and executive processing. As such, these tasks may be able to satisfy the research and clinical demands for a further understanding of these abilities in patients with Attention Deficit/Hyperactivity Disorder (ADHD), a highly prevalent condition in childhood. The relationship between EF and language in children with this disorder were examined through two empirical studies and a literature review. The first study assessed the impact of age and type of school in the performance of 6-to-12-year old children in unconstrained, phonemic and semantic VF tasks (abbreviated as UVF, PVF and SVF, respectively). A total of 378 participants (177 from private schools) with a mean age of 9.03 years (SD=1.91) completed the UVF task, while 403 children (186 from private schools) with a mean age of 9.12 years (SD=1.88) completed were administered the PVF task and 385 children (168 from private schools) with a mean age of 9.01 years (SD=1.86) completed the SVF task. The effect of age and type of school on children s VF performance was assessed using a Two-Way ANOVA, and group differences were investigated using Bonferroni post-hoc tests. Main effects of age and type of school were observed in UVF and PVF scores, while the interaction between these two variables had an effect on SVF. Overall, performance tended to improve with age, and was better in children who attended private schools than in those recruited from public institutions. The second study aimed to perform a review of studies addressing the clinical and/or neuropsychological assessment of linguistic and auditory processing (AP) in children with ADHD. The PubMed database was searched for articles published between 2000 and 2012 using the following keywords [language or linguistic] and [auditory processing or auditory perception] and [attention deficit or hyperactivity]. All abstracts returned were analyzed in parallel by two independent researchers, using a third reviewer for consensus. A total of 46.7% of the studies included in the reviewed focused on language assessment at word and sentence levels, while 33.33% investigated AP and 13.33% assessed both variables. Reading disorders were the most prevalent condition in the samples studied, and, interestingly, the assessments of language and AP were not conducted with the aim of achieving any specific neuropsychological goals. Lastly, the third study in this thesis assessed the impact of the intensity of symptoms of inattention and/or hyperactivity/impulsivity on language, AP, working memory (WM) and the EF of children with ADHD, as well as the relationships and interactions between these variables. Forty-four children with a diagnosis of ADHD took part in the study (33 from private schools, with a mean age of 9.07 years (SD = 1.71)). Correlation analysis was used to select variables for inclusion in a linear regression model. The following results were obtained from this investigation: (1) the intensity of inattention symptoms accounted for a significant portion of the variability reading and writing performance, especially phonological reading and spelling in a writing-to-dictation task; (2) the intensity of hyperactivity/impulsivity symptoms had a significant impact on children s EF (processing speed, cognitive flexibility and inhibitory control), corroborating other findings in the literature; (3) oral language and AP were associated with measures of EF and WM, suggesting that these components are interdependent, although the directionality of their relationship needs to be further explored. In conclusion, the present studies contributed to the understanding of relationships between language and EF in typical childhood development and in children with psychiatric disorders. These findings also have important implications for the neuropsychological assessment and rehabilitation of patients with ADHD.