title: Left hemiparalexia of Chinese characters: neglect dyslexia or disruption of pathway of visual word form processing?
abstract: The objective of the study was to further elucidate the potential mechanisms underlying left hemiparalexia induced by a splenium lesion in corpus callosum. A patient KY, who had infarctions in the splenium and the left ventral medial occipitotemporal area, was examined with neuropsychological tests and fMRI. KY presented left hemiparalexia when he read aloud characters presented in central foveal field tachistoscopically as well as in free-view field. KY also showed left hemialexia for characters in left visual field, while no left hemiparalexia occurred when characters were presented in the right visual field. KY performed poorly in lexical decision tasks. He could judge the directions of Landolt's rings gaps in the left or right visual field equally. The result of fMRI indicated that characters in the left visual field could not activate the visual word form area (VWFA), such as left mid-fusiform cortex. All the above neuropsychological and fMRI findings have provided evidences against the assumption of left hemineglect dyslexia. Instead, they support the mechanism of disconnection of visual word form processing pathway. In conclusion, the evidences suggested that the visual information transmission of characters in the left visual field from right occipital area to the VWFA in the left hemisphere was interrupted by the splenium lesion.
authors.affiliation: Department of Rehabilitation Medicine, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Wenchao
authors.initials: W
authors.lastname: Yi
authors.forename: Ting
authors.initials: T
authors.lastname: Wu
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Ti-fei
authors.initials: TF
authors.lastname: Yuan
authors.forename: Benyan
authors.initials: B
authors.lastname: Luo
authors.forename: Chunlei
authors.initials: C
authors.lastname: Shan
authors.forename: Jianan
authors.initials: J
authors.lastname: Li
authors.forename: Sheng
authors.initials: S
authors.lastname: He
authors.forename: Xuchu
authors.initials: X
authors.lastname: Weng
mesh_terms: D000369:Aged, 80 and over; D044466:Asian People; D003337:Corpus Callosum / Q000473:pathology; D003657:Decision Making; D004411:Dyslexia, Acquired / Q000209:etiology*; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D056784:Leukoencephalopathies / Q000150:complications* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood; D010364:Pattern Recognition, Visual; D011932:Reading; D012660:Semantics; D014793:Visual Cortex / Q000098:blood supply / Q000503:physiopathology*; D014794:Visual Fields / Q000502:physiology*; D014795:Visual Pathways / Q000503:physiopathology*
chemical_list: D010100:Oxygen