Reading Impairment in a Patient with Missing Arcuate Fasciculus

Autor/inn/en	Rauschecker, Andreas M.; Deutsch, Gayle K.; Ben-Shachar, Michal; Schwartzman, Armin; Perry, Lee M.; Dougherty, Robert F.
Titel	Reading Impairment in a Patient with Missing Arcuate Fasciculus
Quelle	In: Neuropsychologia, 47 (2009) 1, S.180-194 (15 Seiten) PDF als Volltext Verfügbarkeit
Sprache	englisch
Dokumenttyp	gedruckt; online; Zeitschriftenaufsatz
ISSN	0028-3932
DOI	10.1016/j.neuropsychologia.2008.08.011
Schlagwörter	Oral Language; Dyslexia; Radiology; Brain; Language Skills; Cognitive Ability; Reading Difficulties; Case Studies; Adolescents; Cancer; Neurological Impairments; Comparative Analysis; Brain Hemisphere Functions; Spatial Ability; Computation; Learning Disabilities; Short Term Memory; Auditory Perception + Suchen Sie Ihr Suchwort? Oral interpretation; Mündlicher Sprachgebrauch; Dyslexics; Legasthenie; Lese-Rechtschreib-Schwäche; Radiologie; Gehirn; Language skill; Sprachkompetenz; Denkfähigkeit; Reading difficulty; Leseschwierigkeit; Case study; Fallstudie; Case Study; Adolescent; Adolescence; Adoleszenz; Jugend; Jugendalter; Jugendlicher; Carcinoma; Karzinom; Krebs (med); Krebserkrankung; Neurodegenerative Erkrankung; Räumliches Vorstellungsvermögen; Learning handicap; Lernbehinderung; Kurzzeitgedächtnis; Auditive Wahrnehmung; Akustische Wahrnehmung; Akustik
Abstract	We describe the case of a child ("S") who was treated with radiation therapy at age 5 for a recurrent malignant brain tumor. Radiation successfully abolished the tumor but caused radiation-induced tissue necrosis, primarily affecting cerebral white matter. "S" was introduced to us at age 15 because of her profound dyslexia. We assessed cognitive abilities and performed diffusion tensor imaging (DTI) to measure cerebral white matter pathways. Diffuse white matter differences were evident in T1-weighted, T2-weighted, diffusion anisotropy, and mean diffusivity measures in "S" compared to a group of 28 normal female controls. In addition, we found specific white matter pathway deficits by comparing tensor-orientation directions in "S's" brain with those of the control brains. While her principal diffusion direction maps appeared consistent with those of controls over most of the brain, there were tensor-orientation abnormalities in the fiber tracts that form the superior longitudinal fasciculus (SLF) in both hemispheres. Tractography analysis indicated that the left and right arcuate fasciculus (AF), as well as other tracts within the SLF, were missing in "S." Other major white matter tracts, such as the corticospinal and inferior occipitofrontal pathways, were intact. Functional MRI measurements indicated left-hemisphere dominance for language with a normal activation pattern. Despite the left AF abnormality, "S" had preserved oral language with average sentence repetition skills. In addition to profound dyslexia, "S" exhibited visuospatial, calculation, and rapid naming deficits and was impaired in both auditory and spatial working memory. We propose that the reading and visuospatial deficits were due to the abnormal left and right SLF pathways, respectively. These results advance our understanding of the functional significance of the SLF and are the first to link radiation necrosis with selective damage to a specific set of fiber tracts. (Contains 7 figures and 2 tables.) (As Provided).
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Update	2017/4/10