Evaluating the Efficacy of Voice Therapy for Neurogenic Voice Disorders

March 11, 2026 updated by: Rosemary Lester-Smith, University of Texas at Austin

Characterization and Treatment of Essential Vocal Tremor

The goal of this study is to evaluate the efficacy of voice therapy for neurogenic voice disorders. The main questions are:

Does voice therapy improve patient-reported quality of life in speakers with neurogenic voice disorders? Does voice therapy improve listener perception of voice in speakers with neurogenic voice disorders? Does voice therapy improve acoustical analyses of voice in speakers with neurogenic voice disorders? Does voice therapy improve physiologic function in speakers with neurogenic voice disorders?

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

Neurogenic voice disorders negatively impact communication-related quality of life for millions of patients. Yet current options for medical treatment including pharmacological and surgical interventions do not consistently improve voice and can have adverse effects. Although some patients with neurogenic voice disorders receive behavioral treatment like voice therapy, systematic treatment research evaluating the efficacy of behavioral treatment is limited. For example, in speakers with voice disorders related to essential tremor, the most common movement disorder in the world, only five studies have evaluated the effects of behavioral interventions. Of these studies, two were case studies (N=1, N=2), two were single-case experiments (N=1, N=3), and one was a prospective group study comparing control and experimental conditions (N=10). These studies evaluated a variety of treatment ingredients using various functional, perceptual, and acoustical treatment outcomes. However, some treatment ingredients and outcome measures were not specific to the underlying voice impairments in essential tremor. In neurogenic voice disorders with other etiologies like dystonia, more studies with larger sample sizes have been conducted. However, only eight studies have been published: two were case studies (N=1, N=1), one was a single-case experiment (N=1), one was a prospective group study comparing pre- and post-treatment phases (N=36), one was a retrospective group study comparing control and experimental conditions (N=37), one was a randomized cross-over study (N=9), one was a non-randomized controlled trial (N=17), and one was a randomized controlled trial (N=31). These studies also evaluated various treatment ingredients using functional, perceptual, and acoustical outcomes, as well as aerodynamic and acoustic outcomes. But again, some treatment ingredients and outcome measures were not specific to the underlying voice impairments related to dystonia. Finally, although a considerably higher number of treatment studies with greater sample sizes have been conducted with speakers who have voice disorders related to Parkinson's disease, the most widely studied treatment ingredients have limitations. For example, Lee Silverman Voice Therapy requires high-intensity, high-frequency treatment provided by speech-language pathologists with specialized training, and expiratory muscle strength training is also high-frequency, high-intensity treatment that requires specific equipment and physiologic capabilities. Thus, there is an important need for systematic treatment research in speakers with neurogenic voice disorders using treatment ingredients and outcome measures that are specific to patients' neurophysiologic impairments and functional limitations.

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Texas
      • Austin, Texas, United States, 78712
        • The University of Texas at Austin

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Diagnosis of essential tremor by a physician
  • Self-reported, physician-identified, or speech-language pathologist-identified vocal tremor
  • Ability to speak and read English
  • Ability to follow instructions and pay attention to tasks

Exclusion Criteria:

  • History of surgery on the oral cavity, larynx, pharynx, or respiratory system that currently affects speech or voice
  • Current respiratory disorder unrelated to essential tremor that affects speech or voice
  • Score 20 points or below on the Mini-Mental Status Examination

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Breathy voice as a compensatory strategy for vocal tremor
Behavioral: Breathy voice
Participants will be trained to produce a breathy voice to reduce the perceptual severity of vocal tremor

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Patient-reported outcome measures
Time Frame: Participants will complete ratings during the treatment phase at the beginning of the first treatment session and at the end of the last treatment session.
Participants will be asked to rate their perception of the voice strategy on a 6-point Likert scale (0 = not at all, 5 = very much): 1) My voice was shaky when I used the strategy, 2) It was effortful to speak when I used the strategy, 3) It was difficult to use the strategy, 4), I liked the sound of my voice when I used the strategy.
Participants will complete ratings during the treatment phase at the beginning of the first treatment session and at the end of the last treatment session.
Auditory-perceptual ratings
Time Frame: Listeners will rate samples from all study phases within two years after all data have been collected from all study participants.
Listeners will be asked to complete perceptual ratings for the participants' voices by marking the severity of the 'shakiness' on a visual-analog scale (0 = not shaky, 100 = very shaky).
Listeners will rate samples from all study phases within two years after all data have been collected from all study participants.
Acoustical analyses - extent of modulation
Time Frame: Audio recordings from all study phases will be analyzed within 2 years after completing data collection.
The extent of fundamental frequency and intensity modulation in percent will be measured in participants' sustained vowels as an estimate of tremor magnitude.
Audio recordings from all study phases will be analyzed within 2 years after completing data collection.
Acoustical analyses - modulation rate
Time Frame: Audio recordings from all study phases will be analyzed within 2 years after completing data collection.
The rate of fundamental frequency and intensity modulation in Hertz will be measured in participants' sustained vowels as an estimate of tremor speed.
Audio recordings from all study phases will be analyzed within 2 years after completing data collection.
Acoustical analyses - cepstral peak prominence
Time Frame: Audio recordings from all study phases will be analyzed within 2 years after completing data collection.
The cepstral peak prominence will be measured in participants' sustained vowels and connected speech as an estimate of 'breathiness.'
Audio recordings from all study phases will be analyzed within 2 years after completing data collection.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Acoustical analyses - voice breaks
Time Frame: Audio recordings from all study phases will be analyzed within 2 years after completing data collection.
The number and duration of voice breaks will be measured in participants' sustained vowels.
Audio recordings from all study phases will be analyzed within 2 years after completing data collection.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Texas at Austin

Investigators

  • Principal Investigator: Rosemary A Lester-Smith, Ph.D., The University of Texas at Austin

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 4, 2024

Primary Completion (Estimated)

June 4, 2028

Study Completion (Estimated)

June 4, 2028

Study Registration Dates

First Submitted

August 15, 2025

First Submitted That Met QC Criteria

March 11, 2026

First Posted (Actual)

March 16, 2026

Study Record Updates

Last Update Posted (Actual)

March 16, 2026

Last Update Submitted That Met QC Criteria

March 11, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 2019010036

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

This study will involve a small sample of speakers with neurogenic voice disorders. The extracted fundamental frequency contours for participants' sustained vowel productions will be made available upon request for research purposes after the data have been published. In addition, deidentified information about participants' medical and voice histories, audio recordings, and rating scale responses will be shared with external collaborators as data are collected and in the future. De-identified coded Data will also be stored and shared through the Texas Data Repository for our modulation analysis output, rating scale, and cognitive test data.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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