Recruiting

tACS

Sponsor:

University of Michigan

Code:

NCT06740968

Conditions

Stuttering, Adult

Stuttering, Childhood

Stuttering, Developmental

Eligibility Criteria

Sex: All

Age: 18 - 65

Healthy Volunteers: Not accepted

Interventions

transcranial alternating current stimulation (tACS)

Study Details

Brief 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. 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.

Conditions

Stuttering, Adult

Stuttering, Childhood

Stuttering, Developmental

Study ID

NCT06740968

Start date

Aug 5, 2025

Status verified date

Sep, 2025

Completion date

Dec, 2029

Anticipated

Primary completion date

Dec, 2029

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 65

Healthy Volunteers: Not accepted

Inclusion Criteria for stutterers:

  • 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

Exclusion Criteria for stutterers:

  • 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

Study Design

Enrollment

80 participants

Anticipated

Allocation

Randomized

Intervention Model

Single group

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

experimental: 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.

Interventions

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).

Primary outcome measure

  • Change in Phase Synchronization [ Time Frame: Baseline (pre-tACS), approximately 3 hours (post-tACS) (visits 3-5) ]

Central Contacts and Locations

Central contacts

Soo-Eun Chang, PhD

734-232-0300sooeunc@umich.edu

Emily Garnett, PhD

734-232-3371emilyog@med.umich.edu

Locations

University of Michigan

Recruiting

Ann Arbor, Michigan, United States, 48109

Contacts

Soo-Eun Chang, PhD

734-232-0300sooeunc@umich.edu

Principal Investigator:

Soo-Eun Chang, PhD

More Information

Sponsor

University of Michigan

Last update posted

Sep 12, 2025

Last verified

Sep, 2025

Keywords

  • tACS
  • Magnetic resonance imaging
  • Electroencephalogram
  • Auditory perturbation
  • Neural oscillations
  • Brain stimulation

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of Michigan on 2025-09-12.