The understanding of complex syntax in children with Down syndrome

Abstract

Background: Down syndrome (DS) is associated with poor language skills that seem disproportionate to general nonverbal ability, but the nature and causes of this deficit are unclear. We assessed how individuals with DS understand complex linguistic constructions, and considered how cognitive ability, memory and hearing level impact the ability of those with DS to process these sentence types. Methods: There were three groups participating in the study: children with DS (n = 33) and two control groups composed of children with cognitive impairment of unknown aetiology (CI) (n = 32) and children with typical development (n = 33). Both groups were matched to those with DS on cognitive ability. Using a newly devised animation task, we examined how well individuals with DS (n = 33) could understand relative clauses, complement clauses and adverbial clauses compared to children with CI and typically developing controls. Participants also completed the Test for the Reception of Grammar-2, three measures of memory (forward and backward digit recall, visuo-spatial memory) and a hearing screen. Results: Results indicated that (1) with the exception of intransitive subject relative clauses, children with DS performed at floor on all other complex sentences, (2) they performed at a significantly lower level than both control groups, and (3) DS status accounted for a significant proportion of the variance over and above memory skills. Conclusions: Our findings suggest that children with DS have a disproportionate difficulty understanding complex sentences compared to two control groups matched on mental age. Furthermore, their understanding of syntax is not completely explained by poor cognitive or memory skills, rather it appears to be a specific deficit that may distinguish children with DS from other neurodevelopmental disorders.

A Review Paper on the Syntactic Abilities of Individuals with Down Syndrome

“…Particularly, concerning their syntactic ability DS individuals tend to produce shorter and less complex utterances compared to typically developing population (Rosin et al, 1988;Chapman et al, 1998;Price et al, 2008;Zampini & D'Odorico, 2011;Galeote et al, 2013;Frizelle et al, 2018), although advances in syntactic complexity may continue into late adolescence and young adulthood. It is also reported that DS group produced not only shorter, less complex utterances overall, but less complex noun phrases, verb phrases, and sentence structures, like questions and negations than did the TD group (Rosin et al, 1988;Chapman et al, 1998Chapman et al, , 2002Vicari et al, 2000;Chapman & Hesketh, 2000;Tsakiridou, 2006;Fabbretti et al, 1997;Stathopoulou, 2007;Price et al, 2007Price et al, , 2008Caselli et al, 2008;Zampini & D'Odorico, 2011).…”

“…Moreover, difficulties emerged in subordination and in coordination, in relative clauses, in adverbial clauses, in finite clauses and in negated constructions (Rondal & Complain, 1996;Joffe & Varlokosta, 2007;Stathopoulou, 2007;Zampini & D'Odorico, 2011;Witecy & Penke, 2017;Polišenská et al, 2018). Additionally, they tended to use infrequently sentence complements, sentential embeddings, or compound sentences (Grela, 2002;Thordardottir et al, 2002;Frizelle et al, 2018). Obviously, the above difficulties increased with sentence length and grammatical complexity, but were also apparent in simple sentences.…”

“…Obviously, the above difficulties increased with sentence length and grammatical complexity, but were also apparent in simple sentences. Overall, the Subject-Verb-indirect/ direct Object was the most frequent multi-argument structure for DS and TDC groups (Zampini & D'Odorico, 2011;Frizelle et al, 2018;Polišenská et al, 2018). On the contrary, results from the Italian language show that syntax does not pose great difficulties on people with DS, since while DS subjects produced significantly larger number of simple clauses, they are able to produce a number of complex sentence structures such as relative clauses and gerund sentences (Fabbretti et al, 1997).…”

“…The area of morphosyntax seems to be more impaired than other domains within the language system, such as lexical abilities, both in receptive and expressive domains (Chapman et al, 1991;Kernan & Sabsay, 1996;Fabbretti et al, 1997;Vicari, 2002;Eadie et al, 2002;Grela, 2002;Abbeduto et al, 2003Abbeduto et al, , 2007Laws & Bishop, 2003;Zampini & D'Odorico, 2011;Draghi & Zampini, 2018;Frizelle et al, 2018;Facon & Magis, 2019; among others).…”

“…Moreover, Frizelle et al (2018) 2017observed that complex sentences were in general understood poorly. With respect to performance on simple sentences, they found that as the number of constituents increases, comprehension becomes more difficult.…”