Narrative Abilities of Adults’ With Down Syndrome as a Window to Their Morphosyntactic, Socio-Cognitive, and Prosodic Abilities

Abstract

Down syndrome (DS) is the most common developmental disorder characterized by mild to moderate intellectual disability. Several studies have reported poor language and prosodic skills and contradictory results regarding individuals' with DS sociocognitive skills, whereas most of them have focused on children with DS. The present study attempts to explore adults' with DS language, socio-cognitive and prosodic abilities via the use of story-retellings. Twenty adults with DS and two groups of TD children, one matched to their expressive vocabulary (TD-EVT) and the other matched to their non-verbal mental age (TD-RCPM), took part in the present study. Participants listened to a story while viewing a wordless picture PowerPoint presentation on a computer screen, and then, they were instructed to retell the story while viewing the pictures for a second time. Each participant listened to two stories, one with "lively" and one with "flat" prosody. Results revealed that adults' with DS performance was comparable with the one presented by the TD-RCPM group, whereas the TD-EVT group performed significantly better in almost all variables. Individuals' with DS renarrations, however, contained significantly less complement clauses and internal state terms (related or not related to Theory of Mind-ToM) compared to the re-narrations of both control groups. In contrast, the group with DS performed similarly to both control groups in comprehension questions related to main characters' internal state terms and significantly better compared to the TD-RCPM group in questions related to ToM. In terms of prosody, all three groups performed significantly better on story structure and comprehension questions when prosody was "lively" compared "flat" prosody. DS group's re-narrations did not contain enough internal state terms, not due to their inability in recognizing them, but due to their poor morphosyntactic abilities, which did not allow them to find the proper means to express the main characters' internal states. Prosody facilitated participants with DS in the comprehension and re-narration. This suggests that intervention programs based on prosody could support the language skills of adults with DS.

Mental State Verb Production as a Measure of Perspective Taking in Narrations of Individuals With Down Syndrome

“…Our findings are consistent with the findings of Grela (2002) who also described similarities of MSV production in a small group of seven children with DS and seven TD children matched by MLU. Our finding of mental-age appropriate production of MSV in individuals with DS is, however, in contrast to the studies of Channell (2020), who described impaired performance of MSV production in her participants with DS in a similar narration task, and Martzoukou et al (2020), who found poorer use of internal state terms in individuals with DS than in cognition-matched TD children. While Channell did not include a control group of TD children against which performance of the DS group could be measured and evaluated as mental-age appropriate, the discrepancy to the findings of Martzoukou et al (2020) awaits explanation.…”

“…Specifically, it does not hinge on the acquisition of subordinate or complement clauses. Our finding that the ability to express perspective taking via MSV use is not dependent on syntactic abilities is also supported by Martzoukou et al (2020) who found morpho-syntactic abilities as measured by a sentence-repetition not to be related to the use of internal state terms.…”

“…Moreover, MLU was significantly lower compared to the control group matched for expressive vocabulary. Based on these findings, Martzoukou et al (2020) conclude that individuals with DS might not be impaired in understanding the internal state of a (fictional) character but that their poor morphosyntactic abilities might limit their expression of internal states.…”

“…MLU as well as a sentencerepetition test were adopted as measures of syntactic ability. Martzoukou et al (2020) report that in comparison to two groups of typically-developing preschool children (each n 20) -one matched by nonverbal cognition, one matched by expressive vocabulary abilities -individuals with DS produced less internal state terms in their re-narrations, although the comprehension questions revealed an adequate understanding of the character's beliefs, thoughts and emotions. In addition, Martzoukou et al report poor morpho-syntactic abilities in their participants with DS reflected in significantly poorer performance in sentence-repetition compared to both groups of control children.…”

“…In a very recent study, Martzoukou et al (2020) investigated narrative abilities of a group of 20 Greek adults with DS (chronological age 19-46 years). The participants were asked to retell two 6-picture-stories from the narrative instrument MAIN after auditory presentation.…”