title: Neural dissociation of phonological and visual attention span disorders in developmental dyslexia: FMRI evidence from two case reports.
abstract: A dissociation between phonological and visual attention (VA) span disorders has been reported in dyslexic children. This study investigates whether this cognitively-based dissociation has a neurobiological counterpart through the investigation of two cases of developmental dyslexia. LL showed a phonological disorder but preserved VA span whereas FG exhibited the reverse pattern. During a phonological rhyme judgement task, LL showed decreased activation of the left inferior frontal gyrus whereas this region was activated at the level of the controls in FG. Conversely, during a visual categorization task, FG demonstrated decreased activation of the parietal lobules whereas these regions were activated in LL as in the controls. These contrasted patterns of brain activation thus mirror the cognitive disorders' dissociation. These findings provide the first evidence for an association between distinct brain mechanisms and distinct cognitive deficits in developmental dyslexia, emphasizing the importance of taking into account the heterogeneity of the reading disorder.
authors.affiliation: CNRS UMR 5105, 38040 Grenoble, France. carole.peyrin@upmf-grenoble.fr
authors.forename: C
authors.initials: C
authors.lastname: Peyrin
authors.forename: M
authors.initials: M
authors.lastname: Lallier
authors.forename: J F
authors.initials: JF
authors.lastname: Démonet
authors.forename: C
authors.initials: C
authors.lastname: Pernet
authors.forename: M
authors.initials: M
authors.lastname: Baciu
authors.forename: J F
authors.initials: JF
authors.lastname: Le Bas
authors.forename: S
authors.initials: S
authors.lastname: Valdois
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001288:Attention / Q000502:physiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000503:physiopathology*; D003072:Cognition Disorders / Q000503:physiopathology; D004410:Dyslexia / Q000503:physiopathology*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000503:physiopathology; D010364:Pattern Recognition, Visual / Q000502:physiology; D010700:Phonetics; D010775:Photic Stimulation; D011932:Reading; D055815:Young Adult