Executive Function, Working Memory, and Verbal Fluency in Relation to Non-Verbal Intelligence in Greek-Speaking School-Age Children with Developmental Language Disorder.

Developmental Language Disorder (DLD) is often associated with impairments in working memory (WM), executive functions (EF), and verbal fluency. Moreover, increasing evidence shows poorer performance of children with DLD on non-verbal intelligence tests relative to their typically developing (TD) peers. Yet, the degree and generality of relevant difficulties remain unclear. The present study aimed at investigating WM capacity, key EFs and verbal fluency in relation to non-verbal intelligence in Greek-speaking school-age children with DLD, compared to TD peers (8-9 years). To our knowledge, the present study is the first to attempt a systematic relevant assessment with Greek-speaking school-age children, complementing previous studies mostly involving English-speaking participants. The results showed that children with DLD scored lower than TD peers on the non-verbal intelligence measure. Groups did not differ in the inhibition measures obtained (tapping resistance to either distractor or proactive interference), but children with DLD were outperformed by TD peers in the WM capacity, updating, monitoring (mixing cost), and verbal fluency (phonological and semantic) measures. The effects showed limited (in the case of backward digit recall) or no dependence on non-verbal intelligence. Findings are discussed in terms of their theoretical and practical implications as well as in relation to future lines of research.

Comorbidity and WISC-III profiles of Greek children with attention deficit hyperactivity disorder, learning disabilities, and language disorders.

The aim of the present study was to (a) examine the prevalence of ADHD and the comorbid difficulties in a sample of 114 children, 3.6 to 17.6 yr. of age (89 boys, 25 girls) referred to our Unit and (b) evaluate the discriminative ability of the WISC-III scores for children with Attention Deficit Hyperactivity Disorder (n = 22), Learning Disability (n = 50), and Language Disorder (n = 42). Analysis showed only 18% of 114 children had an Attention Deficit Hyperactivity Disorder diagnosis. Multivariate analysis of variance and stepwise discriminant function analysis were applied. Vocabulary and similarities were the best predictors for distinguishing between language disorders and the other two groups. Moreover, the Language Disorder group scored significantly lower on all the subtests while the Attention Deficit Hyperactivity Disorder and Learning Disability groups scored lower on coding and information, respectively. Children with Attention Deficit Hyperactivity Disorder and Learning Disability could not be accurately identified from the WISC-III test or their ACID profile.