Abstract
Background & Aims: We tested the Diagnostic and Statistical Manual of Mental Disorders (DSM) hypothesis that so-called specific developmental disorders are marked by a pattern of specific discrepant achievement, and an alternative hypothesis that children with these disorders show a pattern of relatively pervasive low achievement.
Methods & Procedures: Children with a diagnosis of Mixed Receptive Expressive Language Disorder (RELD; n = 21) were compared with children with no previously suspected disorder but low standard language scores ( < 80; n = 22) selected from a representative sample, and children with Developmental Coordination Disorder (DCD; n = 20) were compared with children with no previously suspected disorder but low standard motor skills scores (n = 28) selected from a representative sample.
Outcomes & Results: Children with diagnosed disorders were more pervasive underachievers. The RELD group obtained lower scores on measures of verbal comprehension, emotion understanding, theory of mind, working memory and response inhibition; the DCD group obtained lower scores on measures of perceptual organization, verbal comprehension, receptive and expressive language, and visual inspection time.
Conclusions & Implications: We conclude that relatively pervasive underachievement distinguishes disordered from normal low achievers.
Acknowledgements
This research was supported by grants from the Australian National Health and Medical Research Council and the Research Centre for Applied Psychology, Curtin University of Technology. The authors wish to thank the principals and staff of the participating schools and clinics for their cooperation, and especially the participating children and parents who made this study possible. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.