Stuttering and Neuromodulation

August 31, 2026 updated by: NYU Langone Health
The purpose of this study is to collect preliminary data on the efficacy of transcranial direct current stimulation (tDCS) combined with traditional behavioral techniques to reduce stuttering severity and negative impact in adults who stutter. The study also aims to explore neuroplastic changes (i.e., regional activation and functional connectivity) resulting from combined tDCS + speech therapy.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
16

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Eric S. Jackson
  • Phone Number: 212-992-9470
  • Email: Ej34@nyu.edu

Study Locations

  • United States
    • New York
      • New York, New York, United States, 10016
        • Recruiting
        • NYU Langone Health

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Adults aged 18 to 65 years.
  2. Diagnosis of developmental stuttering, verified by a licensed speech-language pathologist.
  3. Mild-to-moderate or greater stuttering severity, defined as a score of 20 or higher on the Stuttering Severity Instrument-Fourth Edition (SSI-4).
  4. English as a primary language.
  5. Right-handedness (to minimize variability in neural lateralization).
  6. Willing and able to attend all study sessions and follow study procedures.

Exclusion Criteria:

  1. Have a history of neurological, psychiatric, or medical conditions that are contraindicated for tDCS.
  2. Are currently taking medications known to affect cortical excitability.
  3. Have a history of seizures or epilepsy.
  4. Are pregnant or planning to become pregnant during the study period.
  5. Have metal implants in the head (excluding dental work) or other contraindications to electrical brain stimulation.
  6. Any skin disorder or skin sensitive area near stimulation locations.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Behavioral speech therapy combined with active tDCS
Each participant will complete ten treatment sessions over approximately ten weeks. In each session, participants will receive active tDCS for 30 minutes while concurrently engaging in behavioral speech therapy. Active stimulation will include a 30-second ramp-up to 2.0 mA, 30 minutes of continuous stimulation, and a 30-second ramp-down.
Device: Soterix Medical 1x1 tDCS system
Stimulation (2.0 mA for 30 minutes) will occur during speech therapy sessions focused on practicing speech techniques. Sham stimulation will mimic the physical sensation without active current.
Behavioral: Speech therapy sessions
Each of the ten weekly sessions will begin with 15 minutes of strategy practice, providing participants with the opportunity to rehearse light contact and easy onset techniques prior to the tDCS-enhanced speaking task.
Sham Comparator: Behavioral speech therapy combined with sham tDCS
Each participant will complete ten treatment sessions over approximately ten weeks. In each session, participants will receive sham tDCS for 30 minutes while concurrently engaging in behavioral speech therapy. Sham stimulation will involve the same ramp-up and ramp-down but with no current delivered during the 30-minute period to maintain blinding.
Device: Soterix Medical 1x1 tDCS system
Stimulation (2.0 mA for 30 minutes) will occur during speech therapy sessions focused on practicing speech techniques. Sham stimulation will mimic the physical sensation without active current.
Behavioral: Speech therapy sessions
Each of the ten weekly sessions will begin with 15 minutes of strategy practice, providing participants with the opportunity to rehearse light contact and easy onset techniques prior to the tDCS-enhanced speaking task.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in Stuttering Severity Instrument - 4th Edition (SSI-4) total score
Time Frame: Baseline, Visit 15 (~1-2 weeks post-intervention)
The Stuttering Severity Instrument-4th Edition (SSI-4) provides a total score that is compared to age-specific norms to determine severity, with ranges for "Very Mild" to "Very Severe". The SSI-4 calculates individual scores for frequency (2-18), duration (2-18), and physical concomitants (0-20). These individual scores are combined to create a total score, which is then ranked against norms to provide a verbal severity descriptor, such as mild, moderate, severe, or very severe.
Baseline, Visit 15 (~1-2 weeks post-intervention)
Change in the Wright and Ayre Stuttering Self-Rating Profile (WASSP) score
Time Frame: Baseline, Visit 15 (~1-2 weeks post-intervention)
The WASSP produces a profile of scores across five subscales. There is a total of 26 items each scored on a seven-point Likert-type scale. A score of '1' represents the least severe/negative perception, while a '7' represents the most severe/negative perception on each scale. Total scores range from 26-182, with higher scores indicating a greater negative impact of stuttering on their life.
Baseline, Visit 15 (~1-2 weeks post-intervention)
Stuttering impact as assessed by the Overall Assessment of the Speaker's Experience of Stuttering - Adults (OASES-A)
Time Frame: Baseline, Visit 15 (~1-2 weeks post-intervention)
The OASES-A is a tool used by speech-language pathologists to measure the adverse impact of stuttering on an adult's life. It consists of 100 questions rated on a 5-point scale (1-5). The scores from individual questions are added together to create an overall score. The total score is then used to determine the "Impact Rating" on a scale from mild to severe. Higher scores indicate higher levels of negative impact.
Baseline, Visit 15 (~1-2 weeks post-intervention)
Change in the Brief Version of the Unhelpful Thoughts and Beliefs About Stuttering Scales (UTBAS-6) total score
Time Frame: Baseline, Visit 15 (~1-2 weeks post-intervention)
The UTBAS-6 is a six-item screening questionnaire for adults who stutter to measure unhelpful thoughts and beliefs associated with speech anxiety. The UTBAS-6 has a subscale score range of 6 to 30 and a total score range of 18 to 90. A higher score indicates more frequent unhelpful thoughts and greater anxiety related to stuttering.
Baseline, Visit 15 (~1-2 weeks post-intervention)
Change in Brief Fear of Negative Evaluation (BFNE-S) Scale total score
Time Frame: Baseline, Visit 15 (~1-2 weeks post-intervention)
The BFNE-S consists of 8 items that are rated on a five-point likert scale from 1 (not at all characteristic) to 4 (extremely characteristic). Scores range from 0 to 32. A score of 25 or higher may indicate clinically significant social anxiety.
Baseline, Visit 15 (~1-2 weeks post-intervention)
Social Interaction Anxiety Scale (SIAS)
Time Frame: Baseline, Visit 15 (~1-2 weeks post-intervention)
The SIAS is a 20-item self-report questionnaire that measures the severity of social anxiety. Each item is rated from 0 (not at all characteristic or true of me) to 4 (extremely characteristic or ture of me). Scores can range from 0 (no social anxiety) to 80 (maximum social anxiety). A score of 36 or higher is often considered clinically significant, suggesting the presence of social anxiety.
Baseline, Visit 15 (~1-2 weeks post-intervention)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in regional activation in/between cognitive control and speech motor areas during a delayed-naming task
Time Frame: Baseline, Visit 15 (~1-2 weeks post-intervention)
Neuroplastic changes will be assessed using functional near-infrared spectroscopy (fNIRS) to measure cortical activation patterns (i.e., regional activation, functional connectivity) in/between cognitive control and speech motor areas during a delayed-naming task (pre- and post-intervention).
Baseline, Visit 15 (~1-2 weeks post-intervention)
Change in functional connectivity in/between cognitive control and speech motor areas during a delayed-naming task
Time Frame: Baseline, Visit 15 (~1-2 weeks post-intervention)
Neuroplastic changes will be assessed using functional near-infrared spectroscopy (fNIRS) to measure cortical activation patterns (i.e., regional activation, functional connectivity) in/between cognitive control and speech motor areas during a delayed-naming task (pre- and post-intervention).
Baseline, Visit 15 (~1-2 weeks post-intervention)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
NYU Langone Health

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Eric S. Jackson, NYU Langone Health

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 4, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 28, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 28, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 29, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 2, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 31, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 25-00866

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

The de-identified participant data from the final research dataset will be shared upon reasonable request beginning 9 to 36 months after publication or as required by a condition of awards or supporting agreements, provided the requesting researcher provide a methodologically sound proposal and executes a data use agreement with NYU Langone Health. This instance of data sharing will also require separate IRB review as well as review from NYU Langone's Data Sharing Strategy Board (DSSB). Requests should be directed to: Ej34@nyu.edu. The protocol and statistical analysis plan will be posted on Clinicaltrials.gov only as required by federal regulation or supporting awards and agreements.

IPD Sharing Time Frame

Beginning 9 months and ending 36 months following article publication or as required by a condition of awards and agreements supporting the research.

IPD Sharing Access Criteria

Researchers who provide a methodologically sound proposal will be granted access upon reasonable request. Requests should be directed to Ej34@nyu.edu. To gain access, data requestors will need to sign a data access agreement. This instance of data sharing will also require separate IRB review as well as review from NYU Langone's DSSB.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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