Is Specific Learning Disorder Predicted by Developmental Language Disorder? Evidence from a Follow-Up Study on Italian Children

Abstract

Specific Learning Disorder (SLD) is a complex disorder with a strong genetic component, characterized by varying manifestations and considerable differences among children. Several studies have highlighted that difficulties in language acquisition and the presence of Developmental Language Disorders (DLDs) are frequently associated with SLD, suggesting a continuity between the two disorders. This study aimed to add evidence on the proximal and distal predictors of SLD, focusing on the eventual continuity for the presence of DLD at 4–5 years, on some linguistic and communicative abilities at 27–30 months, and on biological and environmental factors. Our sample consisted of 528 families, whose children (Italian monolingual) participated in a screening program at the age of 27–30 months. When children were on average 8.05 years old, parents were asked to answer an interview aimed at collecting information about the children’s language and learning development. Results showed that the prevalence of children with an SLD (7.01%) was in line with those reported in other similar studies. The diagnosis of SLD was significantly predicted by the previous diagnosis of DLD, by male sex/gender, and by the familial risk of SLD. Children with these characteristics had a 54% probability of presenting an SLD.

The High Rates of Comorbidity among Neurodevelopmental Disorders: Reconsidering the Clinical Utility of Distinct Diagnostic Categories

“…During the previous decades, clinicians and researchers recognized the considerable overlap between the two NDDs. For instance, it was found that approximately 55% of SLD (dyslexic) children also met the diagnostic criteria for CD (SLI), while children diagnosed with CD (SLI) also presented significant difficulties in reading acquisition [64]. Other studies provide evidence that children with CD often experience difficulties in literacy skills (reading, writing) [59,[65][66][67][68] and reading comprehension [69][70][71][72].…”

“…Other studies provide evidence that children with CD often experience difficulties in literacy skills (reading, writing) [59,[65][66][67][68] and reading comprehension [69][70][71][72]. In addition, various studies show that children with SLD often present language difficulties [64,[73][74][75].…”

“…As a result, some researchers suggested that a large percentage of these children meet the diagnostic criteria for both disorders, thus confusing clinicians in terms of differential diagnosis and intervention [64]. It was even proposed that SLD (dyslexia) could be categorized as a sub-category of CD [74,76] or that SLI could be considered a more severe form of dyslexia [59].…”

“…For instance, from a genetics perspective, reading and language are both viewed as highly heritable traits, which possibly share common genetic and/or neurobiological influences [64]. Shared genetic factors were also documented between ADHD, reading disorders, and language-related abilities in several studies (e.g., [99][100][101][102][103]), while other studies found a shared genetic etiology between dyslexia and two psychiatric disorders (i.e., schizophrenia and bipolar personality disorder) [104].…”