Transcranial Alternating Current Stimulation (tACS) in Stuttering

NCT06740968 | Recruiting FDA Device

• 1 other identifier: HUM00211167
• Study Type: interventional
• Target: 80
• Locations: 1 country
• Sites: 1

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

Keywords

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

Outcome Measures

Primary Outcomes (1)

• 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.

  Baseline (pre-tACS), approximately 3 hours (post-tACS) (visits 3-5)

Secondary Outcomes (1)

• Percentage of stuttered syllables produced during speech sample

  Baseline (before tACS), approximately 3 hours (post-tACS) (visits 3-5)

Other Outcomes (2)

• Percent change in perturbation response

  Baseline (before tACS), approximately 3 hours (post-tACS) (visits 3-5)

• Change in Phase Amplitude Coupling

  Baseline (before tACS), approximately 3 hours (post-tACS) (visits 3-5)

Study Arms (1)

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.

Device: transcranial alternating current stimulation (tACS)

Interventions

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).

transcranial alternating current stimulation (tACS)

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• University of Michigan: lead

Study Sites (1)

University of Michigan

Ann Arbor, Michigan, 48109, United States

RECRUITING

MeSH Terms

Conditions

Stuttering

Interventions

Transcranial Direct Current Stimulation

Condition Hierarchy (Ancestors)

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

Intervention Hierarchy (Ancestors)

Electric Stimulation Therapy; Therapeutics; Convulsive Therapy; Psychiatric Somatic Therapies; Behavioral Disciplines and Activities; Electroshock; Psychological Techniques

Study Officials

• Soo-Eun Chang, PhD

  University of Michigan

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Soo-Eun Chang, PhD

CONTACT

734-232-0300; sooeunc@umich.edu

Emily Garnett, PhD

CONTACT

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

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: Please note that because the most logical interventional study model is a single arm study the study team can't select a masking option. Please note that Participants, Investigators, and Outcomes Assessors will be blinded to active vs. sham stimulation (with the exception of one study investigator that pre-configures the randomization schedule, and this person will not be involved in any assessments/outcomes).
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor of Psychiatry

Model Details: Participants will all receive the same treatments, however, visits 3 through 5 will have order of conditions (types of stimulation) randomized.

Study Record Dates

• First Submitted: December 14, 2024
• First Posted: December 18, 2024
• Study Start: August 5, 2025
• Primary Completion (Estimated): December 1, 2029
• Study Completion (Estimated): December 1, 2029
• Last Updated: September 12, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)