The Cognitive and Linguistic Abilities of Bilinguals with Genetic Disorders: The Prader-Willi Syndrome Population

Title: The Cognitive and Linguistic Abilities of Bilinguals with Genetic Disorders: The Prader-Willi Syndrome Population
Authors: Garcia Alcaraz, Estela
Date: 2021-02-22
Abstract: The main objective of this dissertation is to investigate the cognitive and linguistic abilities of monolinguals and bilinguals with Prader-Willi Syndrome, a genetic disorder that, among other characteristics, generally involves mild to moderate intellectual disability (see Cassidy et al., 2012). More specifically, we investigate whether and how the fact of speaking two languages may shape the executive control, metalinguistic and narrative abilities of individuals with this syndrome. The study of the effects of bilingualism among non-typically developing individuals is scarce and in its initial stages –being especially limited for individuals with intellectual disabilities (see Kay-Raining Bird et al., 2016 for an overview). Traditionally, non-typically developing individuals have been discouraged from becoming bilingual under the belief that speaking two languages could be counter-productive (Peña, 2016; among others). However, the limited research available, albeit growing, has revealed that these individuals not only become bilingual but also that speaking two languages does not seem to affect them negatively (Cleave et al., 2014; among others). These findings, together with the fact that previous research has mostly highlighted positive outcomes of bilingualism at the executive control, metalinguistic and narrative levels for the typically developing population (Andreou, 2015; Bialystok, 2001; Valian, 2015; among others), led us to explore whether monolingual and bilingual individuals with Prader-Willi Syndrome differed in the three aforementioned areas, and, if so, whether a potential bilingual advantage was attested among this population. We recruited seven Spanish-Catalan early sequential bilingual speakers (M = 18.04 years old, SD = 8.95, age range 10;5-33;10) and eight Spanish monolingual speakers (M = 22.80 years old, SD = 11.58, age range 9;4-47;0) with Prader-Willi Syndrome. Catalan was the dominant language for all bilingual speakers with the exception of one participant, who declared Spanish as his/her dominant language, and both monolingual and bilingual groups were comparable in terms of nonverbal Intelligence Quotient, receptive vocabulary, and sentence recall abilities in Spanish. Participants were administered two executive control tasks, one language driven task (the Stroop task) and one non-language based task (the Flanker task); two metalinguistic tasks (a Sentence Judgment task and a Word-Length Judgment task), and an oral spontaneous narrative task elicited using the Frog Story series. Narratives were analyzed at both the macrostructural and microstructural levels and bilinguals were asked to complete the metalinguistic and the narrative tasks in both Spanish and Catalan. Results yielded similar outcomes for monolinguals and bilinguals at the executive control, metalinguistic and narrative macrostructural levels. However, bilinguals showed a relative advantage at the microstructural narrative level (more vocabulary variability). Thus, our findings not only suggest that individuals with Prader-Willi Syndrome can become bilingual without evidence of negative effects, which is in line with previous research, but also that they can achieve a similar level of performance, or even outperform monolingual speakers in certain linguistic abilities in Spanish –the non-dominant language for the majority of the bilingual participants. Spanish-Catalan bilinguals showed comparable metalinguistic and narrative abilities in both their languages. Despite the fact that inferential statistical analyses did not reveal a significant and consistent bilingual advantage, descriptive data seems to point to it. With all due caution, these results suggest that the effects of bilingualism for the Prader-Willi Syndrome population may be somehow similar to those traditionally proposed for the typically developing population since, when an effect of bilingualism was found, this was positive. These findings are important and constitute a relevant contribution to the field, even though we acknowledge that they are preliminary and should be confirmed with further data.
CollectionThèses, 2011 - // Theses, 2011 -