Between-word speech errors in conduction aphasia

Abstract

Comparisons have been made between the segmental speech errors of conduction aphasics and normal speakers, despite the fact that the aphasic data have involved single-word production and the normal data have involved multi-word production. To provide a more appropriate aphasic database, the sentence repetition of a conduction aphasic (CM) is presented. Errors that resulted from an interaction between the phonemes of two words were examined and compared with past reports of such errors in normal speakers.

Comparisons between the errors of CM and normal speakers revealed similarities, as well as differences. The similarities support the notion that, as with normal speakers, CM's word-interaction errors reflect disruption at the stage of phonemic string construction. For example, the errors of both CM and normal speakers usually involve the interaction of single segments of words from major lexical categories. However, differences exist in the way that such errors are constrained. For example, CM's errors often involve vowels and syllable-final consonants, while the normal errors typically involve word-onsets. These and other differences suggested that CM's word-interaction errors result from the perseveration of segments from one planning phrase to another, as opposed to the mislocation of segments during phonemic string construction, which has been associated with normal speech errors. In the context of a production model, it is argued that CM's pattern of between-word errors reflects an inability to clear a phonemic output buffer.