# Differentiating the Physiological Sources of Modulated Voice

> **NIH NIH R56** · UNIVERSITY OF TEXAS AT AUSTIN · 2024 · $238,500

## Abstract

Project Summary
 Essential tremor (ET) is the most prevalent movement disorder affecting approximately 25 million people
worldwide. Up to sixty-two percent of patients with ET develop vocal tremor (VT) involving oscillation within the
respiratory, laryngeal, pharyngeal-oral, or velopharyngeal-nasal subsystems. These oscillations produce
modulation of the fundamental frequency (pitch) and intensity (loudness) of the voice, resulting in a ‘shaky’
voice and increased effort during speech production. Neurological voice disorders like VT are detrimental to
communication, professional productivity, and quality of life. Unfortunately, the current approaches for medical
management of VT have inconsistent effects on voice production and can have adverse effects. Furthermore,
current methods for behavioral management of VT do not target specific impairments and employ a wide range
of therapeutic techniques leading to inefficient therapy. The challenges in managing VT stem from a lack of
accessible assessment methods to identify the subsystems affected by tremor and guide targeted treatment.
 Clinical assessment of VT requires the use of nasolaryngoscopy to identify oscillation within the larynx and
vocal tract (i.e., pharyngeal-oral and velopharyngeal-nasal subsystems). However, access to
nasolaryngoscopy outside of large voice centers is limited by cost, time, and training demands. Furthermore,
nasolaryngoscopy cannot be used to identify oscillation within the respiratory subsystem, necessitating the
addition of visual and tactile or respiratory kinematic assessments. Although standard acoustical assessments
can be employed in a variety of settings at low cost, current acoustical analyses of microphone signals cannot
differentiate the subsystems affected by tremor because a combination of laryngeal source and vocal tract filter
features are represented.
 Our recent study on vocal vibrato (i.e., a singing technique that involves modulation of voice similar to VT)
used a vibration sensor applied to the neck surface in singers to capture features of the source prior to vocal
tract filtering. Analyses of simultaneously recorded vibration sensor and microphone signals revealed distinct
patterns in the extent of intensity modulation thought to be related to differences in singers’ involvement of the
respiratory system, larynx, and vocal tract in vibrato. In addition, preliminary studies in computational models
and speakers with VT showed distinct patterns of modulation based on the physiological source of tremor.
Thus, the proposed study aims to determine if simultaneously recorded neck-skin vibration sensor and head-
mounted microphone signals differentiate the subsystems involved in voice modulation in singers producing
vibrato as a model of VT and in speakers with VT. Furthermore, the proposed study aims to determine if
vibration sensor and microphone signals capture the effects of laryngeal botulinum toxin injections in speakers
with VT. The findings of thi...

## Key facts

- **NIH application ID:** 11143528
- **Project number:** 1R56DC021972-01
- **Recipient organization:** UNIVERSITY OF TEXAS AT AUSTIN
- **Principal Investigator:** Rosemary Anne Lester-Smith
- **Activity code:** R56 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $238,500
- **Award type:** 1
- **Project period:** 2024-09-01 → 2026-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11143528

## Citation

> US National Institutes of Health, RePORTER application 11143528, Differentiating the Physiological Sources of Modulated Voice (1R56DC021972-01). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/11143528. Licensed CC0.

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