Dastolfo-Hromack, Christina
(2022)
NEURAL CORRELATES OF PHONETIC-INTENSITY ENCODING.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Speech therapy for patients with Parkinson’s disease (PWPD) capitalizes on a physiologic link between vocal intensity and articulation (termed here as ‘phonetic-intensity encoding’), causing a patient’s articulation to improve given the single objective to speak loudly. However, because specific neurological correlates of this effect remain unknown, phonetic-intensity encoding is not described in models of speech motor control. This project investigated the neurological origins of phonetic-intensity encoding within the cortico-basal ganglia loop (precentral gyrus and subthalamic nucleus) using electrophysiologic recordings gathered from patients undergoing deep brain stimulation implantation surgery. Patients were asked to speak nonsense syllables loudly and softly during the awake portion of surgery. Electrophysiologic signals were decomposed into theta band power (4-8 Hz) and gamma band power (70-150 Hz) which were used as the dependent variable in a mixed-effects model, predicted by phoneme identity, vocal intensity and electrode location. Results showed that phonetic-intensity encoding occurs as vocal intensity-dependent increases in theta band power at phoneme-specific locations with the subthalamic nucleus. Simultaneous phonemic and vocal intensity-dependent changes in neural power were observed in precentral gyrus gamma band power, although no interaction between the variables was found. Secondary analysis concluded that both the precentral gyrus and subthalamic nucleus power predict changes in vocal intensity production, although averaged gamma band power displayed a negative association with intensity, while theta band power displayed a positive association. These results confirm hypotheses that the basal ganglia-cortical
loop is involved in vocal intensity processing and the subthalamic nucleus is an important node in phonetic-intensity encoding.
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| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
13 June 2022 |
| Date Type: |
Publication |
| Defense Date: |
16 December 2021 |
| Approval Date: |
13 June 2022 |
| Submission Date: |
12 March 2022 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
199 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
School of Health and Rehabilitation Sciences > Communication Science and Disorders |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
basal ganglia, speech, cortex, precentral gyrus, subthalamic nucleus, voice, voice disorders, gamma, theta, electrophysiology |
| Date Deposited: |
13 Jun 2022 18:57 |
| Last Modified: |
13 Jun 2022 18:57 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/42362 |
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