Electronic Theses and Dissertations Archive

Date

2026

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Communication Sciences & Disorders

Committee Chair

Miriam van Mersbergen

Committee Member

Eugene Buder

Committee Member

Kelsey Mankel

Committee Member

Naomi Eichorn

Committee Member

Rosalba Courtney

Abstract

In functional voice disorders (FVD), voice dysfunction exists in excess or the absence of organic voice pathology. Modern etiologic frameworks emphasize cognitive, emotional, and autonomic processes in the onset and maintenance of symptoms, encapsulating FVD as a subtype of functional neurologic movement disorders (mFND). Despite extensive investigation into emotional aspects of FVD, cognitive aspects, notably attention, remain underexplored. Consequently, the mechanisms which catalyze predisposing factors into physical symptoms are incompletely understood. This multimodal study investigated whether individuals with FVD demonstrated differences in attentional processing and related physiological processes (i.e., breathing and autonomic regulation) compared to individuals with social anxiety (SA) and healthy controls (HC). Participants included 40 adults (75% female; mean age 36). Grouping measures included behavioral and self-report assessments of voice and breathing function and psychological characteristics. Psychophysiological measures of electroencephalography, electrocardiography (heart rate variability; HRV), and respiratory inductance plethysmography captured biomarkers of attention and autonomic function during rest (HRV and theta-beta ratios; TBR) and a Dot Probe Task (event-related potentials) During the experimental task, groups demonstrated similar accuracies, but FVD had significantly slower response times than SA. The N2pc did not capture group differences in visual attentional orienting to stimuli. The P3 indicated group differences in attentional allocation to stimuli conditions, though there was insufficient power to detect specific group contrasts. There were near-significant differences in TBR when controlling for age, with FVD demonstrating higher values, indicating decreased prefrontal control of attention. FVD demonstrated significantly reduced resting HRV compared to the other groups. FVD demonstrated significantly more subjective, but not objective, vocal dysfunction. Both FVD and SA reported significantly more symptoms of dysfunctional breathing (DB), but only one behavioral measure of breathing captured objective DB in FVD. Results were inconclusive regarding attentional function, but trends suggest that in FVD, differences may exist in later, cognitively controlled stages of attention. Voice and breathing evidence suggest that both FVD and SA experience more DB than HC. However, the absence of voice symptoms in SA suggests voice and breathing dysfunction are not necessarily comorbid. Notably, evidence of low HRV in FVD is suggestive of autonomic dysfunction. Overall, subjective and objective measures were consistently incongruent for FVD, suggesting atypical self-awareness.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to ProQuest/Clarivate.

Notes

Open Access

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