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Testing the semantic control hypothesis for stroke aphasics with semantic deficits

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dc.contributor.advisor Martin, Randi
dc.creator Hassan, Azli
dc.date.accessioned 2012-09-06T04:49:03Z
dc.date.accessioned 2012-09-06T04:49:06Z
dc.date.available 2012-09-06T04:49:03Z
dc.date.available 2012-09-06T04:49:06Z
dc.date.created 2012-05
dc.date.issued 2012-09-05
dc.date.submitted May 2012
dc.identifier.uri http://hdl.handle.net/1911/64717
dc.description.abstract Some studies of stroke patients with semantic deficits have found no effect of word frequency on semantic tasks, as well as inconsistent performance across items and tasks. A deficit in semantic control has been suggested as the source of the deficit - i.e., an inability to focus on semantic features appropriate to the task. In the present study, two stroke patients performed significantly better in single-distractor versions (low semantic control) than multiple-distractor versions of semantic tasks (high semantic control) of comprehension tasks, which appears consistent with the semantic control hypothesis. On the other hand, two aphasic patients showed substantially better performance for auditory than visual presentation of words in comprehension tasks – a finding that is not expected on the basis of semantic control. Experiment 1 evaluated whether performance on a multiple-distractor comprehension task could be predicted solely on the basis of performance on a single-distractor version using Luce’s choice axiom. Single distractor performance significantly predicted performance and no convincing evidence was obtained for a role for semantic control. Experiment 2, which examined the modality effect, showed that for one of the patients, worse performance with auditory presentation was most likely due to rapid decay of phonological representations. For the other, worse performance was most likely due to a disruption to phonological representations of words or to their connection to semantic representations. In all, the results suggest that word comprehension deficits in aphasia can result from a variety of sources and not all are due to semantic control deficits.
dc.format.mimetype application/pdf
dc.language.iso eng
dc.subject Semantic Deficit
Aphasia
Semantic Control
Language
Cognitive Psychology, Experimental Psychology, Psychology
dc.title Testing the semantic control hypothesis for stroke aphasics with semantic deficits
dc.contributor.committeeMember Schnur, Tatiana
dc.contributor.committeeMember Lane, David
dc.date.updated 2012-09-06T04:49:06Z
dc.identifier.slug 123456789/ETD-2012-05-197
dc.type.material Text
thesis.degree.department Psychology
thesis.degree.discipline Cognitive Neuroscience
thesis.degree.grantor Rice University
thesis.degree.level Masters
thesis.degree.name Master of Arts
dc.identifier.citation Hassan, Azli. (2012) "Testing the semantic control hypothesis for stroke aphasics with semantic deficits." Masters Thesis, Rice University. http://hdl.handle.net/1911/64717.

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