Semantic memory deficits in low-educated patients with Alzheimer's disease

Chi Cheng Yang, Mau Sun Hua*, Ming Jang Chiu, Sien Tsong Chen, Ping Keung Yip, Ta Fu Chen, Chih Hsun Wu, Ming Ching Wen, Huai Hsuan Tseng, Yi Chuan Chu, Chia Yu Wang, Pei Chong Tu

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

3 Scopus citations


Background/Purpose: Although a deficit of semantic memory is evident in the dementia of the Alzheimer's type (DAT), the underlying neuropsychologic mechanism remains controversial. Breakdown of the semantic network during the course of DAT and an inability to access semantic information have been postulated as possible explanations, but supporting data are limited, particularly in low-educated patients. This study examined semantic memory in low-educated patients with different degrees of dementia severity. Methods: In total, 197 adult subjects were recruited, including 165 DAT patients and 32 normal controls. Subjects were divided into four subgroups according to their dementia severity. All subjects completed an episodic memory task, the Six-Object Memory Test, and semantic memory tasks including the Object Naming Test, the Remote Memory Test and the Semantic Association of Verbal Fluency Test. One-way ANOVA and ANCOVA with a post hoc Scheffe's procedure were used to evaluate differences between groups. Results: All patients, irrespective of the degree of dementia, showed impaired performance on the Six-Object Memory Test [F(4, 163)=69.95, p<0.0001 for immediate recall; F(4, 163)=41.34, p<0.0001 for delayed recall]. On the semantic memory tasks, patients with moderate to severe dementia showed impaired performances on the Object Naming Test [F(4, 180)=28.25, p<0.0001] and the Remote Memory Test [F(4, 167)=26.22, p<0.0001 for recall; F(4, 167)=34.80, p<0.0001 for recognition], while all patients performed defectively on the Semantic Association of Verbal Fluency Test [F(4, 194)=70.43, p<0.0001]. Conclusion: Our results thus partially support the hypotheses that a loss of semantic structure and an inability to access semantic knowledge occur in the pathogenesis of DAT.

Original languageEnglish
Pages (from-to)926-935
Number of pages10
JournalJournal of the Formosan Medical Association
Issue number11
StatePublished - 11 2006
Externally publishedYes


  • Alzheimer's disease
  • Low education
  • Semantic memory


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