Easy-to-read texts for students with intellectual disability: linguistic factors affecting comprehension.

BACKGROUND The use of 'easy-to-read' materials for people with intellectual disabilities has become very widespread but their effectiveness has scarcely been evaluated. In this study, the framework provided by Kintsch's Construction-Integration Model (1988) is used to examine (i) the reading comprehension levels of different passages of the Spanish text that have been designed following easy-to-read guidelines and (ii) the relationships between reading comprehension (literal and inferential) and various linguistic features of these texts. METHOD Sixteen students with mild intellectual disability and low levels of reading skills were asked to read easy-to-read texts and then complete a reading comprehension test. The corpus of texts was composed of a set of forty-eight pieces of news selected from www.noticiasfacil.es, a Spanish digital newspaper that publishes daily journalistic texts following international guidelines for the design of easy-to-read documents (IFLA, Tronbacke B. (1997) Guidelines for Easy-to-read Materials. IFLA, The Hague). RESULTS Participants correctly answered 80% of the comprehension questions, showing significantly higher scores for literal questions than for inferential questions. The analyses of the texts' linguistic features revealed that the number of coreferences was the variable that best predicted literal comprehension, but contrary to what the previous literature seemed to indicate, the relationship between the two variables was inverse. In the case of inferential comprehension, the number of sentences was a significant negative predictor; that is, the higher the sentence density, the lower the ability of these students to find relationships between them. The effects of the rest of linguistic variables, such as word frequency and word length, on comprehension were null. CONCLUSIONS These results provide preliminary empirical support for the use of easy-to-read texts but bring into question the validity of some popular design guidelines (e.g. augmenting word frequency) to optimally match texts and reading levels of students with intellectual disability. Two factors are suggested as contributing to the effect of sentence density on inferential comprehension: (i) long texts present higher conceptual density, so there are more ideas to store, retrieve and integrate, which increases the demand on inferential reasoning and (ii) long texts are perceived as difficult, which affects reading motivation and, consequently, induces passive reading strategies. The need for further research to elucidate the origin of our main findings with a larger and more heterogeneous sample of students with intellectual disability is highlighted.