title: Recovery of semantic word processing in transcortical sensory aphasia: a functional magnetic resonance imaging study.
abstract: In a previous functional magnetic resonance imaging (fMRI) study with normal subjects, we demonstrated regions related to conceptual-semantic word processing around the first frontal sulcus (BA 9) and the posterior parietal lobe (BA 7/40) in agreement with several previous reports. We had the possibility, using the same fMRI paradigm, to study two consecutive cases with left middle cerebral artery (MCA) infarction (RC and HP) and lesions affecting either solely the pre-frontal (HP) or both the pre-frontal and posterior parietal part of the network activated in normal subjects (RC). Both patients showed transcortical sensory aphasia (TSA) on acute assessment. This contradicts classical disconnection accounts of the syndrome stating intact conceptual representations in TSA. Their recovery of language comprehension was associated with activation of a left hemispheric network. Mainly activations of left perilesional pre-frontal regions (RC), left Wernicke's area (RC and HP) or the left posterior middle and inferior temporal cortex (HP) were demonstrated in the TSA patients. The latter findings suggest that in our cases of TSA functional take-over has occurred in regions with related functions ('redundancy recovery') rather than in previously unrelated areas ('vicarious functioning'). Our data support distributed models of conceptual-semantic word processing and multiple left hemispheric representations of closely related functions.
authors.affiliation: Department of Neurology, Neurolinguistics Section, University of Technology, RWTH Aachen, Germany. roland_zahn@psyallg.ukl-freiburg.de
authors.forename: Roland
authors.initials: R
authors.lastname: Zahn
authors.forename: Walter
authors.initials: W
authors.lastname: Huber
authors.forename: Eva
authors.initials: E
authors.lastname: Drews
authors.forename: Karsten
authors.initials: K
authors.lastname: Specht
authors.forename: Stefan
authors.initials: S
authors.lastname: Kemeny
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Reith
authors.forename: Klaus
authors.initials: K
authors.lastname: Willmes
authors.forename: Michael
authors.initials: M
authors.lastname: Schwarz
mesh_terms: D000328:Adult; D000368:Aged; D001041:Aphasia, Wernicke / Q000175:diagnosis / Q000503:physiopathology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology / Q000503:physiopathology; D004292:Dominance, Cerebral / Q000502:physiology; D005500:Follow-Up Studies; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000175:diagnosis / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology; D009473:Neuronal Plasticity / Q000502:physiology*; D009483:Neuropsychological Tests; D011932:Reading; D012016:Reference Values; D012660:Semantics; D013067:Speech Perception / Q000502:physiology