The Role of the Left Temporal Lobe in Naming and Semantic Knowledge

Persistent Link:
http://hdl.handle.net/10150/195781
Title:
The Role of the Left Temporal Lobe in Naming and Semantic Knowledge
Author:
Antonucci, Sharon Mary
Issue Date:
2005
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Background: Anomia is often demonstrated by individuals who sustain damage to the left inferior temporal lobe. The nature of the anomia in individuals with damage to anterior regions of the left temporal lobe (BA 38, 21, 20) has been associated with degradation to semantic knowledge (semantic anomia), while damage to regions farther posterior (BA 37) has been associated with disconnection between preserved semantic knowledge and access to phonological word forms (pure anomia). However, evidence of semantic anomia often comes from individuals with cortical damage that extends beyond left temporal regions, so that it remains unclear whether unilateral damage to this area will result in semantic degradation. Aims: The aim of this study was to examine naming performance in individuals with focal damage to anterior versus posterior regions of the left inferior temporal lobe to determine whether there is a difference in the nature of the observed anomia. Methods: Eight individuals who underwent left anterior temporal lobectomy (L ATL) and eight individuals who sustained left posterior cerebral artery infarcts (L PCA) completed a battery of language measures that assessed lexical retrieval and semantic processing. Sixteen age-and-education matched controls also completed this battery. High resolution structural brain scans were collected for each individual who sustained brain damage. Performance on behavioral measures was examined relative to lesion size and location using statistical analyses. Results: Naming performance ranged from severely impaired to unimpaired in both groups of brain damaged individuals. Both the L ATL and L PCA groups demonstrated well preserved semantic knowledge during lexical retrieval tasks and assessments of semantic knowledge. Naming performance was correlated with lesion volume. Furthermore, a relationship between percent damage to inferior temporal regions, BAs 20 and 21, and naming performance was observed. Conclusion: The behavioral and neuroanatomical evidence indicated that individuals with unilateral damage to left inferior temporal cortex, regardless of anterior versus posterior lesion location, do not demonstrate semantic anomia. These findings suggest that, even in the presence of severe naming impairment, unilateral damage to left inferior temporal cortex is not sufficient to significantly degrade semantic knowledge.
Type:
text; Electronic Dissertation
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Speech, Language, & Hearing Sciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Beeson, Pelagie M
Committee Chair:
Beeson, Pelagie M

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleThe Role of the Left Temporal Lobe in Naming and Semantic Knowledgeen_US
dc.creatorAntonucci, Sharon Maryen_US
dc.contributor.authorAntonucci, Sharon Maryen_US
dc.date.issued2005en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractBackground: Anomia is often demonstrated by individuals who sustain damage to the left inferior temporal lobe. The nature of the anomia in individuals with damage to anterior regions of the left temporal lobe (BA 38, 21, 20) has been associated with degradation to semantic knowledge (semantic anomia), while damage to regions farther posterior (BA 37) has been associated with disconnection between preserved semantic knowledge and access to phonological word forms (pure anomia). However, evidence of semantic anomia often comes from individuals with cortical damage that extends beyond left temporal regions, so that it remains unclear whether unilateral damage to this area will result in semantic degradation. Aims: The aim of this study was to examine naming performance in individuals with focal damage to anterior versus posterior regions of the left inferior temporal lobe to determine whether there is a difference in the nature of the observed anomia. Methods: Eight individuals who underwent left anterior temporal lobectomy (L ATL) and eight individuals who sustained left posterior cerebral artery infarcts (L PCA) completed a battery of language measures that assessed lexical retrieval and semantic processing. Sixteen age-and-education matched controls also completed this battery. High resolution structural brain scans were collected for each individual who sustained brain damage. Performance on behavioral measures was examined relative to lesion size and location using statistical analyses. Results: Naming performance ranged from severely impaired to unimpaired in both groups of brain damaged individuals. Both the L ATL and L PCA groups demonstrated well preserved semantic knowledge during lexical retrieval tasks and assessments of semantic knowledge. Naming performance was correlated with lesion volume. Furthermore, a relationship between percent damage to inferior temporal regions, BAs 20 and 21, and naming performance was observed. Conclusion: The behavioral and neuroanatomical evidence indicated that individuals with unilateral damage to left inferior temporal cortex, regardless of anterior versus posterior lesion location, do not demonstrate semantic anomia. These findings suggest that, even in the presence of severe naming impairment, unilateral damage to left inferior temporal cortex is not sufficient to significantly degrade semantic knowledge.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineSpeech, Language, & Hearing Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorBeeson, Pelagie Men_US
dc.contributor.chairBeeson, Pelagie Men_US
dc.contributor.committeememberKatsanis, Emmanuelen_US
dc.contributor.committeememberLybarger, Lonnieen_US
dc.contributor.committeememberRiggs, Michael W.en_US
dc.contributor.committeememberSo, Magdaleneen_US
dc.identifier.proquest1266en_US
dc.identifier.oclc137354706en_US
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