| Objective: To explore the discourse characteristics of anomic aphasia compared with healthy adults across three discourse tasks based on Mandarin AphasiaBank. Methods: Multi-media samples of 12 anomic aphasia patients and 12 cognitively healthy adults across three discourse tasks (single picture, sequential pictures and story narrative) were collected from Mandarin AphasiaBank. Using CLAN, outcome measures included five discourse characteristic parameters (the number of utterances, mean length of utterance in words, lexical diversity using the moving average type-token ratio, words per minute and proposition density) and word category distributions across different discourse tasks. Results: MMSE scores and AQ scores in aphasia group were significantly lower than those in control group (P<0.05). A mixed ANOVA revealed that there was no interaction between the groups and the discourse tasks. On one hand, the main effect of groups showed that the output of the other four discourse parameters except the number of utterances from the anomic aphasia group was lower than that from the control group significantly. On the other hand, the main effect of tasks revealed that the proposition density and the number of utterances in story narrative were both greater than those in single picture and sequential pictures; the words per minute in story narrative were greater than those in single picture. The proposition density in story natrative was greater than that in single pictrue and sequential pictures (both P<0.05). In the single figure description, WMLU, MATTR and rate of speech and proproposition density in the aphasia group were significantly lower than those in the control group (all P<0.05). In the group narrative, the number of utterances, MATTR and rate of speech in the aphasia group were significantly lower than those in the control group (all P<0.05). In the words per minrte, WMLU, MATTR and rate of speech in the aphasia group were significantly lower than those in the control group (all P<0.05). The less MATTR and words per minute from the anomic aphasia group were found significantly in all three tasks than in the control group. Different discourse tasks had different distribution patterns of word categories between groups. For the anomic aphasia group, there were less nouns, verbs and adverbs significantly in the sequential pictures, more nouns, pronoun and preposition significantly in the single picture description, and more pronoun while less preposition significantly in the story narrative. Conclusions: For anomic aphasia group, the words per minute and lexical diversity were less than those in control group across different discourse tasks. The characteristics of word categories across different discourse tasks from patients of anomic aphasia could be analyzed comparing with the normal control group. There is a new perspective for evaluation and treatment of the aphasia across discourse analysis based on Mandarin AphasiaBank. |
