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Updated: May 13, 2026

Examining the Characteristics of Episodic Memory using Event-related Potentials in Patients with Alzheimer's Disease
Published on: August 30, 2011
Altered categorization of semantic knowledge in Korean patients with Alzheimer's disease
Jae Seung Chang1, Yeon Kyung Chi, Ji Won Han
1Department of Neuropsychiatry, Seoul National University Bundang Hospital, Bundang-Gu, Seongnam, Gyeonggi, Republic of Korea.
Abstract:
Decreased semantic memory has been suggested as an early sign in Alzheimer's disease (AD). This study aimed to investigate qualitative differences in semantic network between AD patients and healthy community-dwelling elderly controls. Category fluency test (animal) was administered to 416 AD patients and 339 controls. Mini-Mental State Examination was administered to evaluate global cognition. Patterns of semantic organization were compared between the two groups using hierarchical clustering (HC) and multidimensional scaling (MDS). In HC analysis, whereas a logically organized semantic structure was observed in the control group with an elaborate use of general knowledge, the semantic structure of the patient group was not interpretable. In MDS mapping, two dimensions of domesticity and size were identified in the control group. The MDS map of AD patients showed mixed features of perception and emotion. Knowledge-based semantic associations may be impaired in AD patients, which can add an extra dimension to cognitive impairments in AD patients regardless of quantitative facets of cognitive dysfunction.
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