Stuttering, AdultNCT06740968
Transcranial Alternating Current Stimulation (tACS) in Stuttering
A study testing transcranial alternating current stimulation (tACS) in people with Stuttering, Adult and Stuttering, Childhood, run by University of Michigan at 1 site in United States.
Trial summary
The purpose of this study is to investigate how mild, noninvasive electrical brain stimulation affects speech relevant brain areas, which may in turn affect speech fluency and speaking-related brain activity in people that stutter. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Stuttering, Adult, Stuttering, Childhood, Stuttering, Developmental
- What is being tested?
- transcranial alternating current stimulation (tACS)
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 80 participants
- Where
- 1 siteUnited States
- Study dates
- 5 Aug 2025to Dec 2029
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Have normal language, hearing, and cognition
- Speak English as the primary language
- Currently stutter
- Score (per protocol) a certain value on the Stuttering Severity Instrument (SSI-4).
- Have not received any treatment for stuttering within the past year
Who cannot join
- History of seizures
- Major medical or neurological illness (e.g., stroke, serious head trauma, brain infection, Parkinson's disease, etc.)
- History of closed head injury with loss of consciousness (e.g., concussion)
- Metal or electronic implants such as cochlear implants and pacemakers anywhere in the body
- Braids or other hair styling that prevents direct access to the scalp (if removal not possible)
- Currently pregnant
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
University of Michigan
Ann Arbor, Michigan, 48109
Soo-Eun Chang, PhD, 734-232-0300, sooeunc@umich.edu
Soo-Eun Chang, PhD
About this study
Official title: Improving Neural Oscillation and Synchrony Between Motor and Auditory Regions in Stuttering Using Personalized Transcranial Alternating Current Stimulation (tACS)
The purpose of this study is to investigate how mild, noninvasive electrical brain stimulation affects speech relevant brain areas, which may in turn affect speech fluency and speaking-related brain activity in people that stutter. The long-term goal of this study is to test the therapeutic potential of transcranial alternating current stimulation (tACS) for the treatment of stuttering.
The study team hypothesizes that if stuttering involves impaired initiation of motor programs, delta-tuned tACS will strengthen communication between brain regions and decrease stuttering. Therefore, delta-tuned sensorimotor tACS will be paired with fluency-induced speech (choral reading), which is hypothesized to decrease stuttering via improved auditory motor integration.
Read the detailed description
Participants will have screening and baseline visits that include a variety of tests and procedures (i.e. standardized tests of speech, language, hearing test, music training questionnaire, working memory tests, and speech sample to characterize stuttering, magnetic resonance imaging (MRI) and electroencephalography (EEG)). Following these, participants will have 3 sessions (active and sham conditions) and then a one month follow-up phone or video call.
Of note, there will be an embedded pilot study to refine the experimental protocol in terms of practicality and feasibility and these participants will not be included in this registration. The only purpose of this embedded study is to refine the protocol and it does not have any health or behavioral outcomes.
- Being tested
- transcranial alternating current stimulation (tACS)
- Keywords
- tACS, Magnetic resonance imaging, Electroencephalogram, Auditory perturbation, Neural oscillations, Brain stimulation
- Medical subject headings
- Stuttering
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
transcranial alternating current stimulation (tACS)Device
During each of the 3 stimulation visits, participants will be seated in a comfortable position and a cap will be placed on participant's head similar to a swimming cap. Small electrodes will be placed near the surface of the scalp at certain regions of interest, and a weak electrical current will be passed through the electrodes into speech related brain areas for 20 minutes. The study team will not use current strengths exceeding 2 milliamps (mA).
| Study group | Role | What they receive |
|---|---|---|
| transcranial alternating current stimulation (tACS) | Experimental | Participants will receive 3 sessions of tACS. Each session can be active or sham. The stimulation parameters regarding the active and sham will not be disclosed at this time to maintain blind to participants. At the end of the trial the study will be updated to list these. Receives: Device: transcranial alternating current stimulation (tACS) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Phase Synchronization
The study will compare EEG data recorded before and after stimulation to determine if tACS contributed to any changes. This will be measured by Phase Locking Value (PLV; measured from 0 to 1) between the two regions targeted by stimulation calculated as [pre(active-sham)] - [post(active-sham)] at each tACS visit.
Measured: Baseline (pre-tACS), approximately 3 hours (post-tACS) (visits 3-5)
Secondary outcomes (1)
Percentage of stuttered syllables produced during speech sample
The study will calculate the percentage of stuttered syllables (out of total syllables) in a speech sample. Decreased stuttered syllables represents better outcomes (greater reduction in stuttering).
Measured: Baseline (before tACS), approximately 3 hours (post-tACS) (visits 3-5)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Dec 2024
- Study start5 Aug 2025
- Primary completionDec 2029 (estimated)
- Study completionDec 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Stuttering, AdultStudies 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
- Randomised
- Intervention model
- Single group
- Model description
- Participants will all receive the same treatments, however, visits 3 through 5 will have order of conditions (types of stimulation) randomized.
- Masking
- None (open label)
- Enrolment
- 80 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Michigan
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Soo-Eun Chang, University of Michigan
- Investigators
- Soo-Eun Chang, PhD, Principal investigator, University of Michigan
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06740968
- Sponsor's protocol ID
- HUM00211167
- Status last verified
- Sep 2026
- First submitted
- 14 Dec 2024
- Last updated
- 13 Oct 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 13 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Improving Neural Oscillation and Synchrony Between Motor and Auditory Regions in Stuttering Using Personalized Transcranial Alternating Current Stimulation (tACS)
- ClinicalTrials.gov ID
- NCT06740968
- Acronym / sponsor ID
- HUM00211167
- Keywords
- tACS, Magnetic resonance imaging, Electroencephalogram, Auditory perturbation, Neural oscillations, Brain stimulation
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 80 participants (estimated)
- Lead sponsor
- University of MichiganUniversity, hospital or other
- Study start
- 5 Aug 2025 (actual)
- Primary completion
- Dec 2029 (estimated)
- Study completion
- Dec 2029 (estimated)
- First posted
- 18 Dec 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to investigate how mild, noninvasive electrical brain stimulation affects speech relevant brain areas, which may in turn affect speech fluency and speaking-related brain activity in people that stutter. The long-term goal of this study is to test the therapeutic potential of transcranial alternating current stimulation (tACS) for the treatment of stuttering.
The study team hypothesizes that if stuttering involves impaired initiation of motor programs, delta-tuned tACS will strengthen communication between brain regions and decrease stuttering. Therefore, delta-tuned sensorimotor tACS will be paired with fluency-induced speech (choral reading), which is hypothesized to decrease stuttering via improved auditory motor integration.
Detailed description
Participants will have screening and baseline visits that include a variety of tests and procedures (i.e. standardized tests of speech, language, hearing test, music training questionnaire, working memory tests, and speech sample to characterize stuttering, magnetic resonance imaging (MRI) and electroencephalography (EEG)). Following these, participants will have 3 sessions (active and sham conditions) and then a one month follow-up phone or video call.
Of note, there will be an embedded pilot study to refine the experimental protocol in terms of practicality and feasibility and these participants will not be included in this registration. The only purpose of this embedded study is to refine the protocol and it does not have any health or behavioral outcomes.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- Participants will all receive the same treatments, however, visits 3 through 5 will have order of conditions (types of stimulation) randomized.
| Arm | Type | Receives |
|---|---|---|
| transcranial alternating current stimulation (tACS) | Experimental | Device: transcranial alternating current stimulation (tACS)Participants will receive 3 sessions of tACS. Each session can be active or sham. The stimulation parameters regarding the active and sham will not be disclosed at this time to maintain blind to participants. At the end of the trial the study will be updated to list these. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Have normal language, hearing, and cognition
- Speak English as the primary language
- Currently stutter
- Score (per protocol) a certain value on the Stuttering Severity Instrument (SSI-4).
- Have not received any treatment for stuttering within the past year
Key exclusion criteria (6 listed)
- History of seizures
- Major medical or neurological illness (e.g., stroke, serious head trauma, brain infection, Parkinson's disease, etc.)
- History of closed head injury with loss of consciousness (e.g., concussion)
- Metal or electronic implants such as cochlear implants and pacemakers anywhere in the body
- Braids or other hair styling that prevents direct access to the scalp (if removal not possible)
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 |
|---|---|---|
| transcranial alternating current stimulation (tACS)During each of the 3 stimulation visits, participants will be seated in a comfortable position and a cap will be placed on participant's head similar to a swimming cap. Small electrodes will be placed near the surface of the scalp at certain regions of interest, and a weak electrical current will be passed through the electrodes into speech related brain areas for 20 minutes. The study team will not use current strengths exceeding 2 milliamps (mA). | Device | transcranial alternating current stimulation (tACS) |
Primary outcome
Change in Phase Synchronization
Time frame: Baseline (pre-tACS), approximately 3 hours (post-tACS) (visits 3-5)
The study will compare EEG data recorded before and after stimulation to determine if tACS contributed to any changes. This will be measured by Phase Locking Value (PLV; measured from 0 to 1) between the two regions targeted by stimulation calculated as [pre(active-sham)] - [post(active-sham)] at each tACS visit.
1 secondary outcome
Percentage of stuttered syllables produced during speech sample
Time frame: Baseline (before tACS), approximately 3 hours (post-tACS) (visits 3-5)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Oct 2026.
- Individual participant dataSharing planned: No
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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.
Soo-Eun Chang, PhD principal investigator
University of Michigan
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing transcranial alternating current stimulation (tACS) in people with Stuttering, Adult and Stuttering, Childhood, run by University of Michigan at 1 site 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 5 inclusion and 6 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: looking for participants now, as of the sponsor's last update on 13 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Soo-Eun Chang, PhD (734-232-0300, sooeunc@umich.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Phase Synchronization (time frame: Baseline (pre-tACS), approximately 3 hours (post-tACS) (visits 3-5)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 13 Oct 2026.