aphasia, apraxia of speech, cognition, stroke, fluency, speech production


Purpose: Slowed speech and interruptions to the flow of connected speech are common in aphasia. These features are also observed during dual task performance for neurotypical adults. The purposes of this study were to determine (a) whether indices of fluency related to cognitive-linguistic versus motor processing would differ between speakers with aphasia plus AOS and speakers with aphasia only and (b) whether cognitive load reduces fluency in speakers with aphasia with and without AOS.

Method: Fourteen speakers with aphasia (seven with AOS) and seven neurotypical controls retold short stories alone (single task) and while simultaneously distinguishing between a high and low tone (dual task). Their narrative samples were analyzed for speech fluency according to sample duration, speech rate, pause/fill time, and repetitions per syllable.

Results: As expected, both speaker groups with aphasia spoke slower and with more pauses than the neurotypical controls. The speakers with AOS produced more repetitions and longer samples than controls, but they did not differ on these measures from the speakers with aphasia without AOS. Relative to the single task condition, the dual task condition increased the duration of pauses and fillers for all groups, but reduced speaking rate only for the control group. Sample duration and frequency of repetitions did not change in response to cognitive load.

Conclusion: Speech output in aphasia becomes less fluent when speakers have to engage in simultaneous tasks, as is typical in everyday conversation. Although AOS may lead to more sound and syllable repetitions than normal, speaking tasks other than narrative discourse might better capture this specific type of disfluency. Future research is needed to confirm and expand these preliminary findings.

Original Publication Citation

Harmon, T. G., Jacks, A., & Haley, K. L. (2019). Speech fluency in acquired apraxia of speech during narrative discourse: Group comparisons and dual-task effects. American Journal of Speech-Langauge Pathology, 28(July), 905–914.

Document Type

Peer-Reviewed Article

Publication Date


Permanent URL


American Speech-Language-Hearing Association




David O. McKay School of Education


Communication Disorders

University Standing at Time of Publication

Assistant Professor