Accuracy-disability versus rate-disability subtypes of dyslexia: A validation study in Arabic

• Published in: Scientific studies of reading Vol. 27; no. 2; pp. 136 - 159
• Main Authors: Shany, Michal, Asadi, Ibrahim, Share, David L.
• Format: Journal Article
• Language: English
• Published: Philadelphia Routledge 04.03.2023; Routledge, Taylor & Francis Group
• Subjects: Accuracy; Arabic; Arabic language; Cognitive linguistics; Dyslexia; Elementary school students; Grade 4; Grammar; Hebrew language; Morphology (Languages); Nonwords; People with disabilities; Phonological Awareness; Phonology; Reading; Reading accuracy; Reading Difficulties; Reading Rate; Reading Skills; Semitic Languages; Student Characteristics; Symptoms (Individual Disorders); Vocabulary; Written Language
• ISSN: 1088-8438; 1532-799X
• DOI: 10.1080/10888438.2022.2106866

We previously reported evidence of true double dissociation between reading accuracy and reading rate in a large unselected sample of Hebrew-speaking fourth graders and a large clinical sample of adult Hebrew-speakers with dyslexia. The present study aimed to replicate and extend these findings to Arabic, which is structurally similar to Hebrew but has distinct linguistic and orthographic features. In a nationally representative 4 th grade sample (N = 236), we show that (1) around one third of children with dyslexia had impaired reading rate but intact accuracy whereas another third had impaired accuracy but intact rate, (2) there was a double dissociation with respect to additional (validation) measures of reading accuracy and rate (pseudowords and text), and (3) the accuracy-only and rate-only disability subtypes displayed distinct and non-overlapping cognitive-linguistic profiles. This evidence converges on the conclusion that accuracy-only and rate-only dyslexic subtypes represent true or "hard" subtypes in an absolute and not merely relative sense. We also found that the accuracy-only subgroup represents a group with broad language weaknesses, primarily phonological but also non-phonological. Finally, we discuss the resemblance between the present rate-accuracy typology and Wolf and Bowers' double-deficit typology.