Classification of reading disability: Identification of subgroups based on domain-specific and domain-general cognitive variables

It has been asserted that children with reading disabilities (RD) constitute a heterogeneous group. This study focuses on classifying reading disabilities by combining two categories of Domain-Specific and Domain-General cognitive variables. In the current study, 56 elementary students from second grade to fifth grade with RD completed a selection of several specific and general cognitive measures. The model-based clustering approach was used to classify the children?s performance. Results revealed three different clusters of RD children: (a) group with reading deficits (word reading, non-word reading, word chain, and picture naming), working memory, and attention-shifting deficits; (b) a group with reading disability (text comprehension) and attention control deficits; and (c) a group with reading disability (rhyme test, word comprehension, phoneme deletion, letter fluency, and category fluency), processing speed, and executive function deficits. These findings imply that different cognitive subtypes of RD can be derived from model-based clustering. The findings strengthen the notion that RD is a heterogeneous disability, provide a basis for an explanatory diagnosis, and can be applied to designing therapeutic protocols specific to reading-disabled individuals.