Combined aphasia and apraxia of speech treatment (CAAST): Systematic replications in the development of a novel treatment.

PURPOSE: The purpose of this investigation was to examine the effects of a modified version of a newly developed therapy for aphasia and acquired apraxia of speech (AOS), Combined Aphasia and Apraxia of Speech Treatment (CAAST).

METHOD: Four speakers with chronic AOS and aphasia received CAAST in the context of multiple baseline designs. Dependent variables included language measures (i.e. production of correct information units (CIUs)) and speech production measures (i.e. speech intelligibility and percent correct consonants (PCC) in sentence repetition).

RESULT: Three of the participants demonstrated improved CIU production with treated picture sets and two also demonstrated generalization to untreated sets. All participants achieved substantially increased CIU production in an untrained discourse context. Speech intelligibility increased for three of the participants and increases in PCC were observed for all of the participants at two weeks post-treatment. However, PCC improvements were maintained for only two of the speakers at six weeks post-treatment.

CONCLUSION: The revised CAAST protocol was associated with improved changes in speech and generalization across contexts in comparison to the previous iteration of CAAST. However, focus on sentence production in generalization practice may have been detrimental to CIU production for one participant.