Subgroup Analysis of 2nd Graders with Developmental Dyslexia Based on Phonological Awareness and Rapid Automatized Naming

Objectives: Phonological processing is a core predictor of reading development in children with dyslexia, and deficits in this area are related to reading difficulties. However, the patterns of deficits are diverse. In particular, it is necessary to examine what patterns emerge when classifying subgroups based on phonological awareness (PA) and rapid automatic naming (RAN). This study aimed to classify and analyze children with dyslexia into subgroups according to PA and RAN and to analyze. Methods: Participants were 97 2nd graders with developmental dyslexia. PA and RAN from the Korean Language-based Reading Assessment (KOLRA) were assessed. Multiple regression analyses were conducted to examine the predictive power of PA and RAN on decoding and reading fluency. Children below 10th percentile were classified into subgroups. In addition, two-step cluster analysis was conducted to confirm the subgroup composition. Results: Regression analyses showed that PA and RAN significantly predicted decoding and reading fluency. Based on the deficit criterion, participants were classified into the double-deficit group (22.7%), PAdeficit group (6.2%), RAN-deficit group (34.0%), and no-deficit group (37.1%). Cluster analysis yielded three groups reflecting differences in PA and RAN, within which the four deficit subgroups were distributed. Conclusion: The findings reconfirm that PA and RAN are key predictors of decoding and reading fluency in children with developmental dyslexia. The results highlight substantial individual differences in PA and RAN performance, underscoring the importance of analyzing individual profiles beyond simple deficit classification. In Korean, a highly transparent orthography, RAN played a particularly important role in reading speed and automatization. These findings emphasize the need for individualized interventions based on PA and RAN.