Effects of Verb Network Strengthening Treatment on Sound-Level and Speech Production Errors in Individuals With Aphasia and Acquired Apraxia of Speech

Abstract

Purpose This retrospective pilot study investigated whether sound-level and speech production errors decreased in confrontation naming following Verb Network Strengthening Treatment (VNeST) for four participants with acquired apraxia of speech (A-AOS) and aphasia for whom lexical retrieval was previously reported. Specifically, we investigated a potential increase in correct number of syllables per word and posttreatment changes across three domains of speech: segmental production, fluency, and prosody. It was hypothesized that treatment shown to increase lexical retrieval in persons with aphasia and A-AOS could potentially facilitate a reduction in sound-level and speech production errors consistent with dual diagnoses of A-AOS and aphasia. Method Naming responses from four participants with aphasia and A-AOS who previously participated in VNeST studies were investigated for correct number of syllables per word and measures of segmental speech, fluency, and prosody. Results Significant gains in at least one measure of speech production were reported for three of the participants. One participant demonstrated decreased segmental speech errors, two showed significant reduction on syllable segmentation, and two demonstrated a significant reduction on false starts and pauses. Significant gains in production of correct number of syllables were limited to one participant, and one participant did not demonstrate increased accuracy on any measure of speech production. Conclusions While speech production errors consistent with motor speech impairment cannot always be definitively distinguished from the confound of aphasia, two participants produced significantly decreased segmentation of syllables, a characteristic unique to A-AOS. The sound-level and speech production changes recorded may be attributed to a combination of interacting motor and language processes and resource allocation. In addition, specific components of VNeST may have contributed to speech production changes. Future work will focus on a prospective study of effects of language therapy (e.g., VNeST) on measures of speech production with investigation beyond the single-word level.