Date of Award

Spring 2016

Degree Name

Bachelor of Science



First Advisor

Elizabeth Casserly


Sensory feedback allows talkers to accurately control speech production, and auditory information is the predominant form of speech feedback. When this sensory stream is degraded, talkers have been shown to rely more heavily on somatosensory information. Furthermore, perceptual speech abilities are greatest when both auditory and visual feedback are available. In this study, we experimentally degraded auditory feedback using a cochlear implant simulation and somatosensory feedback using Orajel. Additionally, we placed a mirror in front of the talkers to introduce visual feedback. Participants were prompted to speak under a baseline, feedback degraded, and visual condition; audiovisual speech recordings were taken for each treatment. These recordings were then used in a playback study to determine the intelligibility of speech. Acoustically, baseline speech was selected as “easier to understand” significantly more often than speech from either the feedback degraded or visual condition. Visually, speech from the visual condition was selected as “easier to understand” significantly less often than speech from the feedback degraded condition. Listener preference of baseline speech was significantly greater when both auditory and somatosensory feedback were degraded then when only auditory feedback was degraded (Casserly, in prep., 2015). These results suggest that feedback was successfully degraded and that the addition of visual feedback decreased speech intelligibility.


Senior thesis completed at Trinity College, Hartford Connecticut for the degree of Bachelor of Science in Neuroscience.