伝導失語とブローカ失語における音の誤りについて

抄録

Phonemic and sub-phonemic analyses were made of speech sound errors exhibited by 3 conduction and 3 Broca's aphasic patients in naming and word repetition tasks. The results indicated the following:
1) In both the naming and word repetition tasks, errors for the conduction aphasics oc-curred both in consonants and vowels, while errors for the Broca's aphasics occurred selecti-vely for consonants.
2) In both the naming and repetition tasks, the percentages of substitution errors and transposition errors in the conduction aphasics were 44% and 44%, respectively; in the Broca's aphasics, however, they were 71% and 17%, respectively.
3) An analysis of the substitution errors in terms of the distinctive feature framework showed that the Broca's aphasics most frequent error sounds (50% of all errors) were those which were different from the target sounds only by one feature in both the naming and repetition tasks. In the conduction aphasics, on the other hand, errors were distributed almost at random in terms of the feature distance in the naming task, while the frequency of one-feature errors increased somewhat in the repetition task.
On the basis of these findings, it was hypothesized that the differences in error patterns between the two types of aphasia reflected differences in the underlying mechanisms of the impairment in each type, i.e., in the conduction aphasics impairment at the level of phonological processing (phoneme retrieval and sequencing) was responsible for their speech sound errors, while in the Broca's aphasics impairment at the phonetic level of the speech production process (programming of articulatory movements), in addition to impairment at the phonological level (phoneme retrieval), was responsible for their errors.