Word lexicality- and regularity-dependent alexia in Alzheimer's disease

Objectives: Despite a great deal of observation on subsequent alexia for Hangeul due to Alzheimer's disease (AD), there is a paucity of research on alexia in Korean AD patients. The purpose of this study is to identify characteristics of alexia of AD according to word lexicality and regularity. Methods: AD patients under GDS 3-6 on the Global Deterioration Scale and NE (normal elderly) groups of 20, were to read aloud three word types (regular words, irregular words, nonwords). Results: The findings revealed that the AD group had significantly higher error frequency when reading regular and irregular words and nonwords compared with the NE group. In addition, there were lexicality and regularity effects in the AD group. From the error analyses of the AD group reading irregular words, visual error was the most frequent, followed by regularization and misapplication of phonological rules. Conclusion: Unsurprisingly, AD patients using Hangeul manifested diverse word classification errors. This research is noteworthy in that it is the first study on the AD subject group reading Hangeul.