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Completed

NCT Number: NCT06875843

Project VOICES: Vocal Optimization in Children Elevating the Spectrum

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.

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Key information

Conditions

Autism Animal Communication Autism Spectrum Disorder Autistic Disorder Behavior Behavior, Animal Child Development Disorders, Pervasive Communication Language Mental Disorders Neurodevelopmental Disorders Vocalization, Animal

Age range

2 year–5 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Vanderbilt University Medical Center

Nashville, Tennessee, 37232, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Contingent responses

Behavioral

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.

Contingent responses plus vocal elicitation strategies

Behavioral

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

Non-contingent control

Behavioral

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.

Primary outcomes

  1. 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.

  2. 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.

  3. 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.

Secondary outcomes

  1. 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.

  2. 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.

  3. 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.

Sponsors and collaborators

Lead sponsor

Vanderbilt University Medical Center

Other

Registry information

Acronym: Project VOICES

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Mar 13, 2025
Registry last updated
Jul 30, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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