Characteristics of Clustering and Switching in Verbal Fluency according to Healthy Elderly Group

Objectives: The purpose of this study was to investigate the characteristics of clusters and switches through verbal fluency tasks by different age groups among the elderly. Methods: Ninety-four healthy elderly adults participated in this study. The verbal fluency task consisted of semantic verbal fluency and phonemic verbal fluency. The categories of 'animal' and 'supermarket' were used for semantic fluency, and the categories'/k/','/o/' and '/s/' were used for phonemic fluency. Results: First, there was a significant difference between the age groups. The number of correct responses in the verbal fluency task decreased as age increased. Second, the mean cluster size for verbal fluency did not show a significant difference among groups in tasks of semantic and phonemic verbal fluency. Third, the number of switches showed a significant difference between groups in semantic and phonemic verbal fluency. In the post-analysis results of semantic fluency, a significant difference was found in the category of'animals' between the young-old and old-old age group, and a significant difference was found in the number of switches in the category of 'supermarket' between the middle-old and old-old age group. Finally, the semantic fluency task showed the highest frequency of perseverative error, and the phonemic fluencytask showed the highest frequency of other errors. Conclusion:These results of this study are meaningful in investigating characteristics of cluster and switch as well as the performance of correct rate through the verbal fluency tasks according to the elderly group.