Reading comprehension difficulties are common in individuals with intellectual disabilities (ID), but the influences of underlying abilities related to reading comprehension in this group have rarely been investigated. One aim of this study was to investigate the Simple View of Reading as a theoretical framework to describe cognitive and linguistic abilities predicting individual differences in reading comprehension in adolescents with non-specific ID. A second aim was to investigate whether predictors of listening comprehension and reading comprehension suggest that individuals with ID have a delayed pattern of development (copying early grade variance in reading comprehension) or a different pattern of development involving a new or an unusual pattern of cognitive and linguistic predictors. A sample of 136 adolescents with non-specific ID was assessed on reading comprehension, decoding, linguistic, and cognitive measures. The hypotheses were evaluated using structural equation models. The results showed that the Simple View of Reading was not applicable in explaining reading comprehension in this group, however, the concurrent predictors of comprehension (vocabulary and phonological executive-loaded working memory) followed a delayed profile.

Cognitive and language abilities influence literacy outcomes in individuals with intellectual disability (ID). The aim of this study was to investigate abilities associated with decoding and reading comprehension in individuals with ID with a systematic review and a correlational meta-analysis. A total of 26 studies with 27 samples and 1,137 participants were included in the meta-analysis. The results showed that reading comprehension was significantly related to decoding ( r = .63), vocabulary ( r = .51), listening comprehension ( r = .43), and IQ ( r = .32). Decoding was significantly related to phonological awareness ( r = .52), phonological short-term memory ( r = .46), rapid automatized naming ( r = −.44), vocabulary ( r = .34), chronological age ( r = .26), IQ ( r = .30), visual short-term memory ( r = .24), and executive-loaded working memory ( r = .32). Limitations connected to unexplained heterogeneity and study quality were found and discussed. This meta-analysis showed that variables identified in studies of typically developing children are relevant for individuals with ID indicating that theories about literacy could reasonably be applied to this population.

Decoding abilities in individuals with intellectual disabilities (ID) are substantially lower than for typical readers. The underlying mechanisms of their poor reading remain uncertain. The aim of this study was to investigate the concurrent predictors of decoding ability in 136 adolescents with non-specific ID, and to evaluate the results in relation to previous findings on typical readers. The study included a broad range of cognitive and language measures as predictors of decoding ability. A LASSO regression analysis identified phonological awareness and rapid automatized naming (RAN) as the most important predictors. The predictors explained 57.73% of the variance in decoding abilities. These variables are similar to the ones found in earlier research on typically developing children, hence supporting our hypothesis of a delayed rather than a different reading profile. These results lend some support to the use of interventions and reading instructions, originally developed for typically developing children, for children and adolescents with non-specific ID.

The semantic network structure is a core aspect of the mental lexicon and is, therefore, a key to understanding language development processes. This study investigated the structure of the semantic network of adolescents with intellectual disability (ID) and children with typical development (TD) using network analysis. The semantic networks of the participants (n_ID = 66; n_TD = 49) were estimated from the semantic verbal fluency task with the pathfinder method. The groups were matched on the number of produced words. The average shortest path length (ASPL), the clustering coefficient (CC), and the network’s modularity (Q) of the two groups were compared. A significantly smaller ASPL and Q and a significantly higher CC were found for the adolescents with ID in comparison with the children with TD. Reasons for this might be differences in the language environment and differences in cognitive skills. The quality and quantity of the language input might differ for adolescents with ID due to differences in school curricula and because persons with ID tend to engage in different out-of-school activities compared to TD peers. Future studies should investigate the influence of different language environments on the language development of persons with ID.

Individuals with intellectual disability (ID) have difficulties with decoding and reading comprehension. However, studies focussing on why these difficulties occur are very sparse, and the existing ...