title: Theories of developmental dyslexia: Insights from a multiple case study of dyslexic adults 
creator: Ramus, Franck
creator: Rosen, Stuart
creator: Dakin, Steven C.
creator: Day, Brian L.
creator: Castellote, Juan M.
creator: White, Sarah
creator: Frith, Uta
subject: Neuropsychology
subject: Developmental Psychology
subject: Psychophysics
subject: Perceptual Cognitive Psychology
subject: Clinical Psychology
subject: Behavioral Neuroscience
description: A multiple case study was conducted in order to assess three leading theories of developmental dyslexia: the phonological, the magnocellular (auditory and visual) and the cerebellar theories. Sixteen dyslexic and 16 control university students were administered a full battery of psychometric, phonological, auditory, visual and cerebellar tests. Individual data reveal that all 16 dyslexics suffer from a phonological deficit, 10 from an auditory deficit, 4 from a motor deficit, and 2 from a visual magnocellular deficit. Results suggest that a phonological deficit can appear in the absence of any other sensory or motor disorder, and is sufficient to cause a literacy impairment, as demonstrated by 5 of the dyslexics. Auditory disorders, when present, aggravate the phonological deficit, hence the literacy impairment. However, auditory deficits cannot be characterised simply as rapid auditory processing problems, as would be predicted by the magnocellular theory. Nor are they restricted to speech. Contrary to the cerebellar theory, we find little support for the notion that motor impairments, when found, have a cerebellar origin, or reflect an automaticity deficit. Overall, the present data support the phonological theory of dyslexia, while acknowledging the presence of additional sensory and motor disorders in certain individuals.
date: 2002
type: Preprint
type: NonPeerReviewed
format: application/pdf
identifier: http://cogprints.org/2350/1/dyslexia02web.pdf
identifier:   Ramus, Franck and Rosen, Stuart and Dakin, Steven C. and Day, Brian L. and Castellote, Juan M. and White, Sarah and Frith, Uta  (2002) Theories of developmental dyslexia: Insights from a multiple case study of dyslexic adults.  [Preprint]    (Unpublished)  
relation: http://cogprints.org/2350/