Weaknesses in Lexical-Semantic Knowledge Among College Students With Specific Learning Disabilities: Evidence From a Semantic Fluency Task

Abstract

Purpose: The purpose of this study is to determine whether deficits in executive function and lexical-semantic memory compromise the linguistic performance of young adults with specific learning disabilities (LD) enrolled in postsecondary studies. Method: One hundred eighty-five students with LD (n = 53) or normal language development (ND, n = 132) named items in the categories animals and food for 1 minute for each category and completed tests of lexical-semantic knowledge and executive control of memory. Groups were compared on total names, mean cluster size, frequency of embedded clusters, frequency of cluster switches, and change in fluency over time. Secondary analyses of variability within the LD group were also conducted.Results: The LD group was less fluent than the ND group. Within the LD group, lexical-semantic knowledge predicted semantic fluency and cluster size; executive control of memory predicted semantic fluency and cluster switches. The LD group produced smaller clusters and fewer embedded clusters than the ND group. Groups did not differ in switching or change over time. Conclusions: Deficits in the lexical-semantic system associated with LD may persist into young adulthood, even among those who have managed their disability well enough to attend college. Lexical-semantic deficits are associated with compromised semantic fluency, and the two problems are more likely among students with more severe disabilities.

Distributional Learning in College Students With Developmental Language Disorder

“…Groups differed on all standardized assessments, which are summarized in Table 2. All participants also participated in a study of semantic fluency and two other studies focused on vocabulary learning (Hall, McGregor, & Oleson, 2017;McGregor, Gordon, Eden, Arbisi-Kelm, & Oleson, 2017), and results supported common findings that the DLD group performs more poorly on language-learning tasks than the group with typical language. See McGregor, Gordon, et al (2017) for a more thorough discussion of participants in this study.…”

“…If we had tested a group with a wider range of abilities, we might have seen differences. However, other research groups have found differences in statistical learning and vocabulary abilities in comparisons of college students with and without DLD (Grunow et al, 2006;Plante et al, 2002;Sheng, Byrd, McGregor, Zimmerman, & Bludau, 2015), as well as in this sample (Hall, McGregor, & Oleson, 2017;McGregor, Gordon, et al, 2017). The Token Task may not have had sufficient spread to adequately show the relationship or may not have been the most sensitive test for measuring grammatical proficiency.…”

Encoding Deficits Impede Word Learning and Memory in Adults With Developmental Language Disorders

“…Given a conservative prevalence estimate of 5% (Nippold & Schwarz, 2002), over 12 million adults in the United States are affected by DLD. The current study is one of a series on word learning and memory among young adults with DLD (Becker & McGregor, 2016;Hall, McGregor, & Oleson, 2017;McGregor et al, 2013McGregor et al, , 2017Sheng et al, 2015).…”

Semantic fluency difficulties in developmental dyslexia and developmental language disorder (DLD): poor semantic structure of the lexicon or slower retrieval processes?

“…With respect to semantic fluency in particular, evidence originates from Hall et al . () who reported that participants with just a reading impairment were more fluent than participants with both language and reading impairments, while participants with language impairment did not differ from either subgroup. Hall et al .…”

“…Further, previous research in Greek has explored the overlap between dyslexia and DLD, and reported that dyslexia and DLD show common deficits in tasks measuring reading skills and reading-related phonological skills (Talli et al 2016, Spanoudis et al 2018, even though they do not completely overlap. With respect to semantic fluency in particular, evidence originates from Hall et al (2017) who reported that participants with just a reading impairment were more fluent than participants with both language and reading impairments, while participants with language impairment did not differ from either subgroup. Hall et al therefore suggest that dyslexia and DLD should not be treated separately.…”