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Active, Not Recruiting

NCT Number: NCT06011837

Effects of Altered Auditory Feedback on Speech Fluency

The purpose of the study is to use altered auditory vocal feedback to increase fluency in people who stutter and to examine changes in this effect over the course of a one month period occurring outside the laboratory setting.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Stuttering, Adult Communication Disorders Language Disorders Nervous System Diseases Neurobehavioral Manifestations Neurologic Manifestations Pathological Conditions, Signs and Symptoms Signs and Symptoms Speech Disorders Stuttering

Age range

18 year–100 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Massachusetts Institute of Technology

Cambridge, Massachusetts, 02139, United States

About this study

The Mumble Melody app applies voice transformations (or "modes") to a user's voice in real-time while they are speaking. The modes include Unaltered, Whisper, Reverberated, and Harmonious voice transformations. The Mumble Melody Longitudinal Study is a month-long online study in which the investigators will be investigating the longer term effects of using the Mumble Melody app for people who stutter. During the course of a month, eligible participants will use the Mumble Melody app daily for however long, on whichever modes, and in whichever settings they wish. Additionally, the investigators will be sending an online platform for participants to conduct weekly at-home testing sessions, in which they will be asked to record their voice during various speech tasks, both with and without the Mumble Melody app. During testing sessions, the investigators will collect voice recordings from participants.

Step 1: Participants will sign a consent form via Redcap. Participants will need an Apple device compatible with the Mumble Melody app.

Step 2: Participants will receive an additional form via Redcap through which they can input information about what device they will be using for the Mumble Melody study, as well as shipping information to receive wired headphones and a headphone jack (which are necessary to use the app).

Step 3: Participants conduct an initial screening session through an online platform, in which they respond to 3 90-second open questions and conduct a passage reading task. The investigators will be collecting voice recordings as they speak within the sessions.

Step 4: Participants' eligibility will be determined using the voice recordings received from step 3. The amount of stuttering-like events and total number of syllables within the recordings will determine if participants have a moderate to severe stutter, meaning they will be eligible for the study.

Step 5: Eligible participants are shipped wired headphones and a headphone jack adapter

Step 6: Participants will fill out an initial survey and optional OASES (Overall Assessment of the Speaker's Experience of Stuttering) assessment of through an online platform.

Step 7: Participants conduct a baseline testing session. During this testing session, participants will answer survey questions, record answers to 2 90-second open response questions without using the Mumble Melody app, follow a step-by-step guide to download and set up the Mumble Melody app, record answers to 2 90-second open response for each of the 4 modes on the Mumble Melody app, and finally record answers to 2 90-second open response questions without using the Mumble Melody app.

Step 8: Step 8: For the following 28 days, participants will be told to use the app as they wish. The investigators will collect app usage logs, which provide timestamps indicating which mode was used and length of use. Participants will receive an additional monetary reward if they use the app for at least 5 minutes for 4 out of 6 days each week.

Step 9: Participants conduct 4 testing sessions, one at the end of each week of the study (day 8, 15, 22, and 29). During each testing session, participants will answer survey questions, record answers to 2 90-second open response questions without using the Mumble Melody app, record answers to 2 90-second open response for each of the 4 modes on the Mumble Melody app, and finally record answers to 2 90-second open response questions without using the Mumble Melody app.

Step 10: After the study, participants will be sent a final survey asking questions on their experience throughout the study and their feedback for the app.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Identifies as a person who stutters
  • Is US citizen or green card holder currently residing in the US
  • Has one of the following Apple devices:
  • iPhone with iOS 12.0 or later
  • iPad with iPadOS 12.0 or later
  • iPod touch with iOS 12.0 or later
  • Mac with macOS 11.0 or later and an Apple M1 chip or later
  • Has a SEPARATE browser-supporting device with a microphone
  • Is able to conduct the study in English
  • Qualifies based on an initial screening evaluation (Greater than 2.5% Stuttering-Like Dysfluencies per syllable)

Exclusion criteria

-

Treatment and study plan

Altered Auditory Feedback

Device

Mumble Melody is an application that leverages Altered Auditory Feedback (AAF). During AAF, a person's speech is altered in near-real time. Mumble Melody modulates the user's voice and plays it back to them while they are speaking. Included are Unaltered (raw voice), Whisper (voiceless sound), Reverb (cathedral sound), and Harmonized (robotic sound) voice transformations.

Other names: Musically Modulated Auditory Feedback, Mumble Melody

Primary outcomes

  1. Significant change in fluency in one of four modes (Unaltered, Whisper, Reverb, Harmonize) between the baseline testing session and the end of week 4.

    Time frame: Calculated at the end of the study for time points 1-week, 2-weeks, 3-weeks, and 4-weeks

    Fluency change From Baseline - Week 4 Measured by Stuttering-Like Dysfluencies within voice recordings from participants

Secondary outcomes

  1. Frequency of Mode Usage

    Time frame: Calculated every day for 4 weeks

    Number of times participants use each modes per day throughout the study

  2. Duration of Mode Usage

    Time frame: Calculated every day for 4 weeks

    Length of times participants use different modes per day throughout the study

  3. Survey data on experience using the application

    Time frame: immediately after the intervention

    A quality of experience survey for participants. This survey includes multiple questions and ratings as described in detail in the study protocol.

  4. Significant change in fluency in one of four modes (Unaltered, Whisper, Reverb, Harmonize) between the baseline testing session and end of week 1, 2, and 3.

    Time frame: Calculated at the end of the study for time points: Baseline, 1-week, 2-weeks, 3-weeks, and 4-weeks

    Fluency change From Baseline - Week 1,2,3 Measured by Stuttering-Like Dysfluencies within voice recordings from participants

  5. Significant change in fluency in the Baseline (No Auditory Feedback) condition between baseline and end of week 1, 2, 3, and 4.

    Time frame: Calculated at the end of the study for time points: Baseline, 1-week, 2-weeks, 3-weeks, and 4-weeks

    Fluency change From Baseline - Week 1,2,3,4 Measured by Stuttering-Like Dysfluencies within voice recordings from participants

  6. Significant change in fluency in the Final (No Auditory Feedback) condition between baseline and end of week 1, 2, 3, and 4.

    Time frame: Calculated at the end of the study for time points: Baseline, 1-week, 2-weeks, 3-weeks, and 4-weeks

    Fluency change From Baseline - Week 1,2,3,4 Measured by Stuttering-Like Dysfluencies within voice recordings from participants

  7. Significant change in fluency for the Final (No Auditory Feedback) condition in comparison to the baseline (No Auditory Feedback) condition, for each testing session

    Time frame: Calculated at the end of the study for time points: Baseline, 1-week, 2-weeks, 3-weeks, and 4-weeks

    Fluency change From Baseline (No Auditory Feedback) - Final (No Auditory Feedback) for each Testing Session Measured by Stuttering-Like Dysfluencies within voice recordings from participants

  8. Significant change in fluency for each mode in comparison to the baseline (No Auditory Feedback) condition, for each testing session

    Time frame: Calculated at the end of the study for time points: Baseline, 1-week, 2-weeks, 3-weeks, and 4-weeks

    Fluency change From Baseline (No Auditory Feedback) - each Mode for each Testing Session Measured by Stuttering-Like Dysfluencies within voice recordings from participants

  9. Significant change in fluency for each non- control mode (Whisper, Reverb, Harmonize) in comparison to the control mode (Unaltered), for each testing session

    Time frame: Calculated at the end of the study for time points: Baseline, 1-week, 2-weeks, 3-weeks, and 4-weeks

    Fluency change From Unaltered Mode - Whisper/Reverb/Harmonize modes for each Testing Session Measured by Stuttering-Like Dysfluencies within voice recordings from participants

Sponsors and collaborators

Lead sponsor

Massachusetts Institute of Technology

Other

Registry information

Important dates

Study start
2023
Primary completion
2024
Study completion
2026
First posted
Aug 25, 2023
Registry last updated
May 14, 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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