Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)

First Advisor

Kim Bauerly

Second Advisor

Shelley Velleman


Movement differences are increasingly recognized as a core autistic trait. Research has primarily focused on fine and gross motor movements of the body. However, emerging research suggests that movements related to speech production and communication may also be different in autistic individuals compared to neurotypical individuals. This research has been conducted using behavioral coding, omnibus tests, and/ or acoustic analyses. This dissertation is composed of three studies that seek to build upon this area of research using motion tracking technologies to examine speech and gesture motor control and coordination in autistic young adults compared to neurotypical young adults. The first study used kinematic technology to examine across-sentence lip movement variability when participants orally repeated sentences varying in length and syntactic complexity. Results showed the autistic group exhibited more variable lip movements and that the complexity of sentences had a greater effect on lip movement for the autistic young adults in comparison to the neurotypical young adults. The second study used kinematic technology to examine the difference in spatial and temporal parameters of lip movements when participants orally produced sentences varying in length under two speaking conditions: habitual versus prosodic modulation. Results showed that the autistic group did not increase the duration of their lip movements as much when speaking under the prosodic manipulation condition relative to the habitual speaking condition in comparison to the neurotypical group. However, the lip movement distances between conditions did not differ between the autistic group and the neurotypical group across conditions. Finally, the third study used simultaneous, multimodal motion tracking technology to examine the temporal coordination of speech and gesture movements while participants completed a structured speaking-gesturing task. Results showed that the timing between speech and gesture movements was more closely aligned in the neurotypical group in comparison to the autistic group; however, group differences were small. Collectively, findings from these three studies provide novel evidence suggesting that speech and other communicative movements are different in autistic young adults compared to neurotypical young adults. Findings emphasize the need for more participant-centered, interprofessional approaches to research in order to understand the nature of these communicative movement differences in autistic individuals.



Number of Pages

216 p.

Available for download on Sunday, June 22, 2025