StutteringNCT04929184

Speech Processing in Stuttering

A study testing Speech and non-speech tasks in people with Stuttering and Stuttering, Childhood, run by University of Michigan at 2 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

This research is being done to better understand stuttering, specifically how people who stutter may process and/or produce speech. Eligible participants enrolled will complete a variety of computer and speech-based tasks on up to 2 visits. Read more about this study

Who is it for?: Ages 6 to 65 yearsHealthy volunteers can take part
Conditions the study is for: Stuttering, Stuttering, Childhood, Stuttering, Adult
What is being tested?: Speech and non-speech tasks
Type of treatment: Lifestyle or therapy programme
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 145 participants
Where: 2 sitesUnited States
Study dates: 4 Apr 2022to 16 Jun 2025
Phase: Interventional
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 6 to 65 years
All sexes
Healthy volunteers accepted
Child, Adult, Older adult

Who may be able to join

18-65 years old
English as primary language
Normal speech, language, hearing, cognition
Aged 18-65 years
English as primary language
Normal speech, language, hearing, cognition (other than stuttering)

Show all 14Show fewer

Currently stutters
Aged 6 to 17 years
English as primary language
Normal speech, language, hearing, cognition
Aged 6 to 17 years
English as primary language
Normal speech, language, hearing, cognition (other than stuttering)
Currently stutters

Who cannot join

Personal or family history of stuttering
Major medical or psychiatric illness
Speech therapy within the past year
Major medical or psychiatric illness
Personal or family history of stuttering
Major medical or psychiatric illness

Show all 9Show fewer

Language/motor delay
Major medical or psychiatric illness
Language/motor delay

Trial locations and contacts

2 sites in 1 country.

United States2 sites

University of Michigan
Ann Arbor, Michigan, 48109
Michigan State University
East Lansing, Michigan, 48824

Other trials in United States

About this study

Read the detailed description

The study team will update the record to include the secondary identification number once the NIH has released the funds.

Conditions: Stuttering, Stuttering, Childhood, Stuttering, Adult
Being tested: Speech and non-speech tasks
Keywords: Healthy children, Healthy Adults
Medical subject headings: Stuttering

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Speech and non-speech tasksBehavioural
Participants will complete speech tasks such as listening to and/or producing speech and non-speech sounds.

Study groups in NCT04929184
Study group	Role	What they receive
Adults who stutter (AWS)	Experimental	Participants will have 2 visits. Receives: Behavioral: Speech and non-speech tasks
Healthy Adults	Other	Participants will have 2 visits. Receives: Behavioral: Speech and non-speech tasks
Children who Stutter	Experimental	Participants will have 1 visit. Receives: Behavioral: Speech and non-speech tasks
Healthy Children	Other	Participants will have 1 visit. Receives: Behavioral: Speech and non-speech tasks

What is being measured

The primary outcome is the main question the study is designed to answer.

Phase Locking Value (PLV) - Session 1 Speech Tasks
Participants will hear a series of single syllables spoken rhythmically and will be instructed to whisper the syllable "tah" repeatedly while the recording is playing.
The degree of synchronization (how well the participant's whispered syllables match the cadence of the recorded syllables they are listening to) will be measured by computing the PLV between subject's produced speech and the heard speech. The PLV is a vector with a value between 0 and 1 that reflects the phase difference between two signals, where 0 is a complete mis-match and a 1 is a perfect match. Adults were not instructed to attempt to match the cadence (Implicit task). Child participants were instructed to attempt to match the cadence (Explicit task).
Measured: Session 1 (up to 4 hours)
Phase Locking Value (PLV) - Session 2 Speech Tasks
Adult participants will hear a series of single syllables spoken rhythmically and will be instructed to whisper the syllable "tah" repeatedly while the recording is playing. Child participants did not attend Session 2.
The degree of synchronization (how well the participant's whispered syllables match the cadence of the recorded syllables they are listening to) will be measured by computing the PLV between subject's produced speech and the heard speech. The PLV is a vector with a value between 0 and 1 that reflects the phase difference between two signals, where 0 is a complete mis-match and a 1 is a perfect match. Adults completed this task twice. For the first test, they were not instructed to attempt to match the cadence (Implicit task). For the second test, they were instructed to attempt to match the cadence (Explicit task).
Measured: Session 2 (up to 4 hours)

Secondary outcomes (1)

R Statistic (Resultant Vector Length)
In tapping synchronization (sensorimotor synchronization) research, the R statistic generally refers to the resultant vector length derived from circular statistics, used to quantify the consistency and stability of a participant's tapping relative to a rhythmic stimulus. It ranges from 0 to 1. 0=Complete inconsistency (taps are uniformly distributed). 1=Perfect consistency (all taps occur at the exact same relative phase).
Measured: Session 1 (up to 4 hours)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

4 Apr 202216 Jun 2025

First posted18 Jun 2021
Study start4 Apr 2022
Primary completion16 Jun 2025
Study completion16 Jun 2025

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for StutteringStudies of the same condition, open and under way.
More trials run by University of MichiganThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase N/A
Primary purpose: Basic science
Allocation: Non-randomised
Intervention model: Single group
Masking: None (open label)
Enrolment: 145 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT04929184
Sponsor's protocol ID: HUM00194953
Other IDs: 1R21DC019429-01
Status last verified: Jul 2026
First submitted: 10 Jun 2021
Last updated: 16 Jul 2026
Results posted: Yes, on ClinicalTrials.gov
FDA-regulated drug: No
FDA-regulated device: No
Individual data sharing: No

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

Recruiting
Using Non-invasive Brain Stimulation to Explore Potential Treatments to Reduce Speech Errors in Adults Who Stutter
Stuttering, Fluency Disorder
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Network Connectivity and Temporal Processing in Adolescents Who Stutter
Stuttering, Childhood, Stuttering
Recruiting
Transcranial Alternating Current Stimulation (tACS) in Stuttering
Stuttering, Adult, Stuttering, Childhood
Not yet recruiting
Effectiveness of Virtually Simulated Intervention for Patients Having Stuttering
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Not yet recruiting
Development and Pilot Testing of Virtually Simulated Intervention for Patients Having Stuttering
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All Stuttering trials

Study at a glance

From the registry record, last updated by the sponsor on 16 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Speech Processing in Stuttering
ClinicalTrials.gov ID: NCT04929184
Acronym / sponsor ID: HUM00194953
Conditions: Stuttering, Stuttering, Childhood, Stuttering, Adult
Keywords: Healthy children, Healthy Adults
Study type: Interventional
Recruitment status: Completed
Enrolment: 145 participants (actual)
Lead sponsor: University of MichiganUniversity, hospital or other
Collaborators: National Institute on Deafness and Other Communication Disorders (NIDCD)
Study start: 4 Apr 2022 (actual)
Primary completion: 16 Jun 2025 (actual)
Study completion: 16 Jun 2025 (actual)
First posted: 18 Jun 2021 (actual)
Results: Posted 16 Jul 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

The study team will update the record to include the secondary identification number once the NIH has released the funds.

Study design

Primary purpose: Basic science
Allocation: Non-randomised
Intervention model: Single group
Masking: None (open label)
Number of arms: 4

Arm	Type	Receives
Adults who stutter (AWS)	Experimental	Behavioral: Speech and non-speech tasksParticipants will have 2 visits.
Healthy Adults	Other	Behavioral: Speech and non-speech tasksParticipants will have 2 visits.
Children who Stutter	Experimental	Behavioral: Speech and non-speech tasksParticipants will have 1 visit.
Healthy Children	Other	Behavioral: Speech and non-speech tasksParticipants will have 1 visit.

Who may qualify

Ages: 6 to 65 years
Sex: All
Healthy volunteers: Accepted
Age groups: Child, Adult, Older adult

Key inclusion criteria (14 listed)

18-65 years old
English as primary language
Normal speech, language, hearing, cognition
Aged 18-65 years
English as primary language

Key exclusion criteria (9 listed)

Personal or family history of stuttering
Major medical or psychiatric illness
Speech therapy within the past year
Major medical or psychiatric illness
Personal or family history of stuttering

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Speech and non-speech tasksParticipants will complete speech tasks such as listening to and/or producing speech and non-speech sounds.	Behavioural	Adults who stutter (AWS), Children who Stutter, Healthy Adults, Healthy Children

Primary outcome

Phase Locking Value (PLV) - Session 1 Speech Tasks
Time frame: Session 1 (up to 4 hours)
Participants will hear a series of single syllables spoken rhythmically and will be instructed to whisper the syllable "tah" repeatedly while the recording is playing. The degree of synchronization (how well the participant's whispered syllables match the cadence of the recorded syllables they are listening to) will be measured by computing the PLV between subject's produced speech and the heard speech. The PLV is a vector with a value between 0 and 1 that reflects the phase difference between two signals, where 0 is a complete mis-match and a 1 is a perfect match. Adults were not instructed to attempt to match the cadence (Implicit task). Child participants were instructed to attempt to match the cadence (Explicit task).
Phase Locking Value (PLV) - Session 2 Speech Tasks
Time frame: Session 2 (up to 4 hours)
Adult participants will hear a series of single syllables spoken rhythmically and will be instructed to whisper the syllable "tah" repeatedly while the recording is playing. Child participants did not attend Session 2. The degree of synchronization (how well the participant's whispered syllables match the cadence of the recorded syllables they are listening to) will be measured by computing the PLV between subject's produced speech and the heard speech. The PLV is a vector with a value between 0 and 1 that reflects the phase difference between two signals, where 0 is a complete mis-match and a 1 is a perfect match. Adults completed this task twice. For the first test, they were not instructed to attempt to match the cadence (Implicit task). For the second test, they were instructed to attempt to match the cadence (Explicit task).

1 secondary outcome

R Statistic (Resultant Vector Length)
Time frame: Session 1 (up to 4 hours)

Results and safety

Results posted to the registry on 16 Jul 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Adults Who Stutter (AWS)	55	45
Healthy Adults	67	53
Children Who Stutter (CWS)	13	13
Healthy Children	10	10

Primary outcome: Phase Locking Value (PLV) - Session 1 Speech Tasks

Time frame: Session 1 (up to 4 hours). Mean (Standard Deviation). Unit: PLV

Measure	Adults Who Stutter (AWS) n = 43	Healthy Adults n = 51	Children Who Stutter (CWS) n = 13	Healthy Children n = 10
Implicit	0.42 (0.15)	0.42 (0.14)	–	–
Explicit	–	–	0.42 (0.15)	0.44 (0.21)

Population analysed: Adults only completed the implicit task on visit 1. Only children completed the explicit task on visit 1 (their only visit).

Primary outcome: Phase Locking Value (PLV) - Session 2 Speech Tasks

Time frame: Session 2 (up to 4 hours). Mean (Standard Deviation). Unit: PLV

Measure	Adults Who Stutter (AWS) n = 43	Healthy Adults n = 51	Children Who Stutter (CWS) n = 0	Healthy Children n = 0
Implicit	0.43 (0.15)	0.42 (0.16)	–	–
Explicit	0.56 (0.22)	0.57 (0.24)	–	–

Population analysed: Children did not complete Visit 2.

1 secondary outcome is reported in the full results.

Adverse events

Time frame: From enrollment to study completion, up to two weeks.. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Adults Who Stutter (AWS)	0 of 55 (0%)	0 of 55 (0%)	0 of 55
Healthy Adults	0 of 67 (0%)	0 of 67 (0%)	0 of 67
Children Who Stutter (CWS)	0 of 13 (0%)	0 of 13 (0%)	0 of 13
Healthy Children	0 of 10 (0%)	0 of 10 (0%)	0 of 10

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 16 Jul 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Individual participant dataSharing planned: No

Related trials for Stuttering

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Using Non-invasive Brain Stimulation to Explore Potential Treatments to Reduce Speech Errors in Adults Who Stutter
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Recruiting
Network Connectivity and Temporal Processing in Adolescents Who Stutter
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Recruiting
Transcranial Alternating Current Stimulation (tACS) in Stuttering
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Not yet recruiting
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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Emily Garnett, PhD principal investigator

University of Michigan

2 sites in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A study testing Speech and non-speech tasks in people with Stuttering and Stuttering, Childhood, run by University of Michigan at 2 sites in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 14 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 16 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 16 Jul 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Phase Locking Value (PLV) - Session 1 Speech Tasks (time frame: Session 1 (up to 4 hours)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04929184.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Jul 2026.