Verbal Fluency in Aphasia

—Word Class and Time-Course Analyses—

Abstract

We administered five verbal fluency tasks that required production of "animals," "vegetables" (common nouns), "company names," "famous people's names" (proper nouns), and things people do (verbs). Each task was administered with a 60-second time limit. The subjects were 32 individuals with aphasia, and their performance was compared with the performance of healthy young and healthy elderly groups reported by Lee et al (2013). The results indicated that the number of correct responses was significantly fewer in the aphasic group than in both healthy groups. The number of correct responses of proper nouns and verbs was significantly fewer than that of common nouns in all the groups. Correlations between the number of correct responses of common noun fluency and the Naming subtest of the Standard Language Test of Aphasia (SLTA) were moderately significant; however, correlations between verb fluency and the Verb Naming subtest of SLTA were not significant. Therefore, naming tasks may not be substituted with verbal fluency tasks in the assessment of aphasia. The number of correct responses in each fluency task was also analyzed within four 15-second time intervals. The results revealed that the performance consistently declined during four consecutive intervals in both healthy groups, especially in the animal and vegetable tasks. On the other hand, in the aphasic group, decline in performance was not clear during the second to the fourth intervals. This suggests that people with aphasia need more time to retrieve words.