In this doctoral project, a computerized screening tool to assess reading skills in monolingual and bilingual students has been developed based on an extensive revision of the literature (Chapter 1) and a meta-analytic study (Chapter 2). In particular, the meta-analytic study allowed us to identify universal and orthographic-specific markers of DD across European countries and to obtain an overview of all behavioral/cognitive impairments associated with reading failures. The Language-Free Screening Tool included, in its original version, 12 computer-based non-verbal tasks hierarchically organized. In chapter 3, a detailed description of the Language-Free Screening Tool is presented together with a validation study on Italian monolingual students of primary and middle school. Each task's predictive power was assessed on 142 Italian-monolingual participants with (N = 37) and without (N = 105) reading difficulties or dyslexia using logistic regression models. Once isolated the pool of tasks capable of predicting reading difficulties, their construct validity was tested using a PCA. Finally, a classification and regression tree (CART) model was trained on Italian-monolingual participants to obtain a multivariate set of classification rules (Chapter 3). To prove the "language-free" nature of this computerized tool, we also tested a group of bilingual children (N = 51): although they showed, on average, a disadvantage in lexical decoding (as measured with standard clinical tests for Italian speakers), they did not underperform Italian monolinguals in any task of the Language-Free Screening Tool (Chapter 4). This result represents our proof of concept to consider the screening suitable for both monolingual and bilingual students. Finally, to assess whether some bilingual participants were to consider at risk of dyslexia, the multivariate set of rules identified in Chapter 3 were applied to the whole sample of bilinguals, returning a classification of children as “poor” or “good readers.” This classification was compared to the one that we would have obtained by adopting standard clinical reading tests. The results of the whole project will be discussed in light of causal models of DD and their implications for clinicians and public education.
At the root of dyslexia: a language-free approach for the identification of reading disorders in monolingual and bilingual children.
Carioti, Desirè
2021
Abstract
In this doctoral project, a computerized screening tool to assess reading skills in monolingual and bilingual students has been developed based on an extensive revision of the literature (Chapter 1) and a meta-analytic study (Chapter 2). In particular, the meta-analytic study allowed us to identify universal and orthographic-specific markers of DD across European countries and to obtain an overview of all behavioral/cognitive impairments associated with reading failures. The Language-Free Screening Tool included, in its original version, 12 computer-based non-verbal tasks hierarchically organized. In chapter 3, a detailed description of the Language-Free Screening Tool is presented together with a validation study on Italian monolingual students of primary and middle school. Each task's predictive power was assessed on 142 Italian-monolingual participants with (N = 37) and without (N = 105) reading difficulties or dyslexia using logistic regression models. Once isolated the pool of tasks capable of predicting reading difficulties, their construct validity was tested using a PCA. Finally, a classification and regression tree (CART) model was trained on Italian-monolingual participants to obtain a multivariate set of classification rules (Chapter 3). To prove the "language-free" nature of this computerized tool, we also tested a group of bilingual children (N = 51): although they showed, on average, a disadvantage in lexical decoding (as measured with standard clinical tests for Italian speakers), they did not underperform Italian monolinguals in any task of the Language-Free Screening Tool (Chapter 4). This result represents our proof of concept to consider the screening suitable for both monolingual and bilingual students. Finally, to assess whether some bilingual participants were to consider at risk of dyslexia, the multivariate set of rules identified in Chapter 3 were applied to the whole sample of bilinguals, returning a classification of children as “poor” or “good readers.” This classification was compared to the one that we would have obtained by adopting standard clinical reading tests. The results of the whole project will be discussed in light of causal models of DD and their implications for clinicians and public education.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
