Project VOICES: Vocal Optimization in Children Elevating the Spectrum (Project VOICES)

July 28, 2026 updated by: Jena McDaniel, Vanderbilt University Medical Center
Thirty percent of children with autism barely talk or do not talk at all despite years of intervention. This study aims to address this important and long-standing challenge by developing a novel intervention to increase the quantity and quality of vocalizations (i.e., sounds children make before words) and expressive language in young children with autism (aged 2 to 5 years) with minimal verbal skills. The intervention includes contingent responses to the child's vocalizations and vocal elicitation strategies. We also collect social validity information from parents about how they perceive the novel intervention.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

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.

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 (Actual)

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.
3

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 Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • Tennessee
      • Nashville, Tennessee, United States, 37232
        • Vanderbilt University Medical Center

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

  • Child

Accepts Healthy Volunteers

No

Description

Child participants

  • Inclusion criteria

    • Diagnosed with autism spectrum disorder
    • Aged 2 to 5 years old
    • Use no more than 20 words (spoken, signed, or via augmentative and alternative communication) per parent report
    • Use of < 5 different words during a 15-min communication sample
    • Use of at least one consonant (observed or reported)
    • Primary language of English

  • Exclusion criteria

    • Uncorrected visual or hearing impairment
    • Evidence of severe motor impairment

Caregiver participants

• Inclusion criteria

  • Have a child enrolled in the study (One caregiver per child participant is enrolled.)
  • Sufficient English skills to complete surveys

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: Contingent responses
Participants engage in three conditions: (a) contingent responses, (b) contingent responses with vocal elicitation strategies, (c) non-contingent control
Behavioral: Contingent responses
The adult systematically responds to more complex child vocalizations with more complex responses. When the child first vocalizes, the adult imitates that vocalization. The child's response determines the next adult response. If the child produces a vocalization within 3 seconds, the adult imitates the child, provides a linguistic map (i.e., puts the apparent meaning into words), and complies nonverbally with the child's apparent intent (e.g., giving item or action). If the child does not produce another vocalization within 3 seconds, the adult remains quiet until the child vocalizes again.
Behavioral: Contingent responses plus vocal elicitation strategies
The adult follows the contingent responses condition protocol with the addition of using vocal toys (e.g., echo tubes, microphones that distort voices, and microphones that amplify voices) within exciting turn-taking activities/routines (e.g., blowing bubbles, balloons, and whoopee cushions). The vocal elicitation strategies emphasize the need to help children vocalize to initiate child-adult interactions. These strategies may be especially important for children who vocalize infrequently to benefit from other intervention aspects and enhance their spoken language skills. The vocal elicitation strategies are to be used when needed, rather than being obligatory for every adult-child interaction. If the child vocalizes without a vocal elicitation prompt, the adult still responds to the vocalization
Behavioral: Non-contingent control
The adult provides non-contingent vocal responses based on audio recordings from prior contingent responses condition sessions transmitted via a wireless earpiece. Recordings from these yoked sessions control for number and type of adult vocalizations and minimize the degree of contingency between adult and child vocalizations in this condition.

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
Proportion of children for whom the contingent responses with vocal elicitation strategies condition is successful for increasing quantity of vocalizations
Time Frame: Baseline to up to 8 weeks
The investigators will calculate the proportion of children for whom the contingent responses with vocal elicitation strategies condition is successful based on the child producing more non-vegetative vocalizations in the contingent responses with vocal elicitation strategies condition than the non-contingent control condition.
Baseline to up to 8 weeks
Proportion of children for whom the contingent responses condition is successful for increasing quantity of vocalizations
Time Frame: Baseline to up to 8 weeks
The investigators will calculate the proportion of children for whom the contingent responses is successful based on the child producing more non-vegetative vocalizations in the contingent responses condition than the non-contingent control condition.
Baseline to up to 8 weeks
Proportion of children for whom the contingent responses with vocal elicitation strategies condition provides added value for increasing quantity of vocalizations
Time Frame: Baseline to up to 8 weeks
The investigators will calculate the proportion of children for whom the contingent responses is successful based on the child producing more non-vegetative vocalizations in the contingent responses with vocal elicitation strategies condition than the contingent responses condition.
Baseline to up to 8 weeks

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
Proportion of children for whom the contingent responses with vocal elicitation strategies condition is successful for increasing quality of vocalizations
Time Frame: Baseline to up to 8 weeks
Description: The investigators will calculate the proportion of children for whom the contingent responses with vocal elicitation strategies is successful based on the child producing more vocalizations with canonical syllables, more communicative vocalizations, or a higher diversity of key consonants used in communication acts in the contingent responses with vocal elicitation strategies condition than the non-contingent control condition.
Baseline to up to 8 weeks
Proportion of children for whom the contingent responses condition is successful for increasing quality of vocalizations
Time Frame: Baseline to up to 8 weeks
Description: The investigators will calculate the proportion of children for whom the contingent responses is successful based on the child producing more vocalizations with canonical syllables, more communicative vocalizations, or a higher diversity of key consonants used in communication acts in the contingent responses condition than the non-contingent control condition.
Baseline to up to 8 weeks
Proportion of children for whom the contingent responses with vocal elicitation strategies condition provides added value for increasing quality of vocalizations
Time Frame: Baseline to up to 8 weeks
Description: The investigators will calculate the proportion of children for whom the contingent responses with vocal elicitation strategies condition is successful based on the child producing more vocalizations with canonical syllables, more communicative vocalizations, or a higher diversity of key consonants used in communication acts in the contingent responses with vocal elicitation strategies condition than the contingent responses condition.
Baseline to up to 8 weeks

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.
Vanderbilt University Medical Center

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.
April 25, 2025

Primary Completion (Actual)

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.
July 24, 2026

Study Completion (Actual)

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.
July 24, 2026

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).
March 7, 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 7, 2025

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 13, 2025

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.
July 30, 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.
July 28, 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.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

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.
  • 250043

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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