Production variability and single word intelligibility in aphasia and apraxia of speech

This study was designed to estimate test–retest reliability of orthographic speech intelligibility testing in speakers with aphasia and AOS and to examine its relationship to the consistency of speaker and listener responses. Monosyllabic single word speech samples were recorded from 13 speakers with coexisting aphasia and AOS. These words were transcribed phonetically by two trained listeners and also presented to non-brain-damaged listeners for identification in a computerized speech intelligibility test. Overall intelligibility scores were computed for each speaker, and word-by-word responses for individual words were examined for both speaker and listener consistency. The clinical feasibility of the approach was supported by a strong correlation between scores from the phonetic transcription and speech intelligibility tests and by strong test–retest reliability for all speakers. Detailed analyses of individual responses indicated that the intelligibility test stability was not due to consistency either in the kind of errors speakers made or in the responses listeners gave when they heard a word different from the target.Learning outcomes: The reader will be able to describe the purpose of single word speech intelligibility testing in individuals with aphasia and apraxia of speech and to discuss the relationship between word-by-word production consistency and overall test–retest reliability.