ERIC Number: EJ1109503
Record Type: Journal
Publication Date: 2016
Abstractor: As Provided
Five Describing Factors of Dyslexia
Tamboer, Peter; Vorst, Harrie C. M.; Oort, Frans J.
Journal of Learning Disabilities, v49 n5 p466-483 Sep-Oct 2016
Two subtypes of dyslexia (phonological, visual) have been under debate in various studies. However, the number of symptoms of dyslexia described in the literature exceeds the number of subtypes, and underlying relations remain unclear. We investigated underlying cognitive features of dyslexia with exploratory and confirmatory factor analyses. A sample of 446 students (63 with dyslexia) completed a large test battery and a large questionnaire. Five factors were found in both the test battery and the questionnaire. These 10 factors loaded on 5 latent factors (spelling, phonology, short-term memory, rhyme/confusion, and whole-word processing/complexity), which explained 60% of total variance. Three analyses supported the validity of these factors. A confirmatory factor analysis fit with a solution of five factors (RMSEA = 0.03). Those with dyslexia differed from those without dyslexia on all factors. A combination of five factors provided reliable predictions of dyslexia and nondyslexia (accuracy >90%). We also looked for factorial deficits on an individual level to construct subtypes of dyslexia, but found varying profiles. We concluded that a multiple cognitive deficit model of dyslexia is supported, whereas the existence of subtypes remains unclear. We discussed the results in relation to advanced compensation strategies of students, measures of intelligence, and various correlations within groups of those with and without dyslexia.
Descriptors: Dyslexia, Correlation, Factor Analysis, College Freshmen, Foreign Countries, Regression (Statistics), Causal Models, Item Response Theory, Predictor Variables, Questionnaires, Spelling, Phonology, Short Term Memory, Rhyme, Sight Method
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Publication Type: Journal Articles; Reports - Research
Education Level: Higher Education; Postsecondary Education
Authoring Institution: N/A
Identifiers - Location: Netherlands (Amsterdam)
Grant or Contract Numbers: N/A