Comparison of Word Reading between Cognitively Normal Elderly and Elderly with Mild Cognitive Impairment according to Word Condition

Purpose: The purpose of this study was to compare word reading performance according to word condition between cognitively normal elderly and elderly with mild cognitive impairment. Methods: We studied 21 patients with mild cognitive impairment (MCI) and 21 age-, sex-, and education-matched cognitively normal older adults. Participants were asked to administer a reading aloud task under four different word conditions (regular words, regular nonwords, irregular words, irregular nonwords). Results: First, the MCI group scored significantly lower compared to the normal elderly group in irregular both words and nonwords. Although there were no significant group differences in regular words and regular nonwords, both groups showed poor performance in the order of irregular nonwords, irregular words, regular nonwords, and regular words. Second, from the error analyses, the MCI group made more ‘regularization’ errors than the normal elderly group in both irregular words and irregular nonwords. Also, in regular nonwords, the MCI group made more ‘phonological errors’ than the elderly group. Conclusion: Our findings suggest that MCI adversely affects lexical routes for reading irregular words. Also, decreased performance in irregular nonwords requiring both reading routes represents the the lexical route is impaired and the phonologicl route is not fully preserved in MCI.