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

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: Recruiting
• Conditions: Autism
• Intervention / Treatment: Behavioral: Contingent responses; Behavioral: Contingent responses plus vocal elicitation strategies; Behavioral: Non-contingent control

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jena McDaniel, PhD; Phone Number: 615-936-5114; Email: jena.mcdaniel@vumc.org

Study Locations

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

Participation Criteria

Eligibility Criteria

• 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

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

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

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	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	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	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

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	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	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	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

• Sponsor: Vanderbilt University Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): April 25, 2025
• Primary Completion (Estimated): July 1, 2028
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: March 7, 2025
• First Submitted That Met QC Criteria: March 7, 2025
• First Posted (Actual): March 13, 2025

Study Record Updates

• Last Update Posted (Actual): May 7, 2026
• Last Update Submitted That Met QC Criteria: May 6, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Language; Children; Autism; Vocalizations
• Additional Relevant MeSH Terms: Autism Spectrum Disorder; Mental Disorders; Neurodevelopmental Disorders; Child Development Disorders, Pervasive; Behavior; Behavior, Animal; Communication; Animal Communication; Autistic Disorder; Language; Vocalization, Animal
• Other Study ID 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