title: The relationships between the amount of spared tissue, percent signal change, and accuracy in semantic processing in aphasia.
abstract: Recovery from aphasia, loss of language following a cerebrovascular incident (stroke), is a complex process involving both left and right hemispheric regions. In our study, we analyzed the relationships between semantic processing behavioral data, lesion size and location, and percent signal change from functional magnetic resonance imaging (fMRI) data. This study included 14 persons with aphasia in the chronic stage of recovery (six or more months post stroke), along with normal controls, who performed semantic processing tasks of determining whether a written semantic feature matched a picture or whether two written words were related. Using region of interest (ROI) analysis, we found that left inferior frontal gyrus pars opercularis and pars triangularis, despite significant damage, were the only regions to correlate with behavioral accuracy. Additionally, bilateral frontal regions including superior frontal gyrus, middle frontal gyrus, and anterior cingulate appear to serve as an assistive network in the case of damage to traditional language regions that include inferior frontal gyrus, middle temporal gyrus, supramarginal gyrus, and angular gyrus. Right hemisphere posterior regions including right middle temporal gyrus, right supramarginal gyrus, and right angular gyrus are engaged in the case of extensive damage to left hemisphere language regions. Additionally, right inferior frontal gyrus pars orbitalis is presumed to serve a monitoring function. These results reinforce the importance of the left hemisphere in language processing in aphasia, and provide a framework for the relative importance of left and right language regions in the brain.
authors.affiliation: Aphasia Research Laboratory, Boston University, Sargent College of Health and Rehabilitation Sciences, 635 Commonwealth Ave., Boston MA 02215, USA. Electronic address: jordyn.sims@gmail.com.
authors.forename: Jordyn A
authors.initials: JA
authors.lastname: Sims
authors.affiliation: Aphasia Research Laboratory, Boston University, Sargent College of Health and Rehabilitation Sciences, 635 Commonwealth Ave., Boston MA 02215, USA.
authors.forename: Kushal
authors.initials: K
authors.lastname: Kapse
authors.affiliation: Northwestern University, Feinberg School of Medicine, 303 Chicago Ave., Chicago, IL 60611, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Glynn
authors.affiliation: Pennsylvania State University, College of Health and Human Development, Ford Building, State College, PA 16801, USA.
authors.forename: Chaleece
authors.initials: C
authors.lastname: Sandberg
authors.affiliation: Department of Biostatistics, School of Public Health, Boston University, 801 Massachusetts Ave., Boston, MA 02118, USA.
authors.forename: Yorghos
authors.initials: Y
authors.lastname: Tripodis
authors.affiliation: Aphasia Research Laboratory, Boston University, Sargent College of Health and Rehabilitation Sciences, 635 Commonwealth Ave., Boston MA 02215, USA. Electronic address: kirans@bu.edu.
authors.forename: Swathi
authors.initials: S
authors.lastname: Kiran
mesh_terms: D000368:Aged; D001037:Aphasia / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000502:physiology; D002908:Chronic Disease; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000473:pathology / Q000503:physiopathology; D007807:Language Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D025341:Principal Component Analysis; D012660:Semantics
chemical_list: D010100:Oxygen
keywords: Aphasia; Language recovery; Lesion mapping; Regions of interest (ROI); fMRI