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

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
40

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
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

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
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

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
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

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Texas at Austin

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • 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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 4, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 4, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 4, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 15, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 11, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 16, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 16, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 11, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant 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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