title: Language representation in a patient with a dominant right hemisphere: fMRI evidence for an intrahemispheric reorganisation.
abstract: Studies have suggested that congenital left hemispheric (LH) frontal arteriovenous malformations (AVMs) are associated with an early transfer of language to right hemisphere (RH) frontal regions. The question remains whether such anatomofunctional reorganisation is due to RH compensatory abilities or to a general principle of lateral shift. In this study, we used fMRI language paradigms to investigate the case of a patient presenting aphasic symptoms following an haemorrhage due to a right frontal AVM. Prior to surgery, fMRI showed that language processing was confined to the RH, suggesting that language had not shifted during childhood from this congenitally dominant RH to the LH. After surgery, the patient presented severe aphasia that recovered to presurgical level within 70 days. At this time, fMRI showed that language tasks were still not associated with activations in the LH. These results suggest that the principles of early cerebral reorganisation after congenital lesions may differ in the RH and the LH. In addition, they support the idea that efficient restoration of language is achieved if a sufficiently large neuronal network is preserved around the lesion.
authors.affiliation: Department of Radiology, Geneva University Hospital, 24, rue Micheli-du-Crest, CH-1211 Geneva 14, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Seghier
authors.forename: F
authors.initials: F
authors.lastname: Lazeyras
authors.forename: S
authors.initials: S
authors.lastname: Momjian
authors.forename: J M
authors.initials: JM
authors.lastname: Annoni
authors.forename: N
authors.initials: N
authors.lastname: de Tribolet
authors.forename: A
authors.initials: A
authors.lastname: Khateb
mesh_terms: D000328:Adult; D001037:Aphasia / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology*; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D007802:Language; D007807:Language Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000033:anatomy & histology / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D020127:Recovery of Function / Q000502:physiology*; D014705:Verbal Behavior / Q000502:physiology*