• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.337-340
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• 1999

The most salient and discussed features of speech production in agrammatic aphasia are the omission and substitution of grammatical morphemes. Cross-linguistic studies have shown that the pattern of omission/substitution is not random but occurs in a systematic and highly constrained way. Although these descriptions are important, they do not explain why all grammatical morphemes are not equally impaired. Friedmann and Grodzinsky (1997) proposed the Tree-Pruning Hypothesis (TPH) to account for these patterns of sparing and loss. The TPH claims that in an agrammatic representation, an impaired functional node is underspecified, thus allowing inappropriate affixation to occur. Additionally, whenever a node is impaired, all nodes above it will also be impaired. Using four types of narratives collected from two Korean agrammatic patients, We test the claim that the impairment in agrammatism is based on such hierarchical representation. It was found that these patients consistently produced appropriate grammatical morphemes that are higher in a syntactic tree than the impaired morphemes. The finding that an intact node exists higher than an impaired node refutes the TPH.

• Korean Journal of Cognitive Science
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• v.13 no.2
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• pp.15-23
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• 2002

This paper reports an experiment on Broca's aphasics' comprehension of a class of English constructions involving empty categories. Based on Grodzinsky's (1986) account of chance-level performance of agrammatic understanding of movement constructions and their thematic role assignments. I show that Grodzinsky's notion of invisible empty categories can be further extended to include pronomical anaphors (PRO's) in Chomsky's (1981) sense and that the asymmetry in their poor comprehension of subject- and object-control constructions can be explained by the heuristic mechanism of the default thematic role assignment rule. eventually supporting Grodzinsky's claim that empty categories are not visible In agrammatic's syntactic representation.

• Dementia and Neurocognitive Disorders
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• v.17 no.3
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• pp.110-119
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• 2018

Background and Purpose: To analyze $^{18}F-THK5351$ positron emission tomography (PET) scans of patients with clinically diagnosed nonfluent/agrammatic variant primary progressive aphasia (navPPA). Methods: Thirty-one participants, including those with Alzheimer's disease (AD, n=13), navPPA (n=3), and those with normal control (NC, n=15) who completed 3 Tesla magnetic resonance imaging, $^{18}F-THK5351$ PET scans, and detailed neuropsychological tests, were included. Voxel-based and region of interest (ROI)-based analyses were performed to evaluate retention of $^{18}F-THK5351$ in navPPA patients. Results: In ROI-based analysis, patients with navPPA had higher levels of THK retention in the Broca's area, bilateral inferior frontal lobes, bilateral precentral gyri, and bilateral basal ganglia. Patients with navPPA showed higher levels of THK retention in bilateral frontal lobes (mainly left side) compared than NC in voxel-wise analysis. Conclusions: In our study, THK retention in navPPA patients was mainly distributed at the frontal region which was well correlated with functional-radiological distribution of navPPA. Our results suggest that tau PET imaging could be a supportive tool for diagnosis of navPPA in combination with a clinical history.

• Korean Journal of Cognitive Science
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• v.9 no.1
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• pp.41-46
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• 1998

The argument-structure distributions of predicates in the speech of two roca-type aphasic patients and one Conduction-type patient are compared with both matched controls and each other on the basis of narrative production data. Whereas English-speaking agrammatics have been reported to have difficulties producing noncopular unaccusative predicates (Kegl 1995) Korean-speaking agrammatics are found not to have particular difficulties with unaccusative predicates. On the assumption that agrammatics lack specific syntactic knowledge for the processing of displaced arguments from their lexically specified positions. it is proposed that unaccusatives in Korean do not involve the displacement of arguments for Case-theoretic reasons or involve a vacuous movement. if any.