NCT03437512

Non-invasive Brain Stimulation in Adults Who Stutter

Terminated NA Results posted Last updated 29 April 2021

What this trial tests

NA trial testing Anodal tDCS in Stuttering, Developmental in 29 participants. Terminated before completion.

Timeline

25 June 2018

Primary endpoint
1 April 2020

1 April 2020

Quick facts

Lead sponsor	University of Michigan
Phase	NA
Status	Terminated
Study type	INTERVENTIONAL
Allocation	randomized
Design	parallel
Masking	quadruple
Primary purpose	treatment
Enrollment	29
Start date	25 June 2018
Primary completion	1 April 2020
Estimated completion	1 April 2020
Sites	1 location across United States

Drugs / interventions tested

• Anodal tDCS
• Fluency training
• Sham tDCS

Conditions studied

• Stuttering, Developmental — all drugs for Stuttering, Developmental →

Sponsor

University of Michigan

Who can join

Adults 18 to 65, any sex, with Stuttering, Developmental. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Changes in Brain Activation as Assessed by fMRI Images Primary · Baseline, 1 week (post), 4 weeks (follow up)

Investigators will use the fMRI images taken from before and after tDCS to determine if the treatment intervention contributed to any changes within brain regions associated with speech production. This will be measured by Blood-Oxygen-Level-Dependent (BOLD) signal change (arbitrary units). Images from scans are preprocessed. Changes in BOLD signal are modeled for contrasts within a group for \[post-pre\] and \[follow up-pre\] (e.g., active group reading condition post visit MINUS active group reading pre visit). Results are reported for reading condition.

left supplementary motor area (SMA) (post-pre)

Group	Value	95% CI
Active tDCS and Fluency Training	1.39	± 0.45
Sham tDCS and Fluency Training	0.81	± 0.47

left SMA (fol-pre)

Group	Value	95% CI
Active tDCS and Fluency Training	1.03	± 0.49
Sham tDCS and Fluency Training	0.9	± 0.54

right SMA (post-pre)

Group	Value	95% CI
Active tDCS and Fluency Training	-0.45	± 0.48
Sham tDCS and Fluency Training	0.49	± 0.52

right SMA (fol-pre)

Group	Value	95% CI
Active tDCS and Fluency Training	0.86	± 0.54
Sham tDCS and Fluency Training	0.09	± 0.35

left superior temporal gyrus (STG) (post-pre)

Group	Value	95% CI
Active tDCS and Fluency Training	1.43	± 0.74
Sham tDCS and Fluency Training	0.79	± 0.75

left STG (fol-pre)

Group	Value	95% CI
Active tDCS and Fluency Training	0.09	± 0.53
Sham tDCS and Fluency Training	0.57	± 0.85

right STG (post-pre)

Group	Value	95% CI
Active tDCS and Fluency Training	-0.63	± 0.97
Sham tDCS and Fluency Training	1.56	± 1.39

right STG (fol-pre)

Group	Value	95% CI
Active tDCS and Fluency Training	0.3	± 1.07
Sham tDCS and Fluency Training	0.83	± 1.17

Change in Percentage of Stuttered Syllables Produced During Speech Sample Primary · Baseline, 1 week (post), 4 weeks (follow up)

Investigators 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).

% Change post

Group	Value	95% CI
Active tDCS and Fluency Training	-1.82	± 2.22
Sham tDCS and Fluency Training	1.06	± 2.02

% Change follow up

Group	Value	95% CI
Active tDCS and Fluency Training	-1.03	± 4.17
Sham tDCS and Fluency Training	3.46	± 5.47

Changes From Baseline on the Overall Assessment of Speakers Experience of Stuttering (OASES) Secondary · Baseline, 1 week (post), 4 weeks (follow up)

The OASES is a standardized assessment of the functional impact of stuttering on a person's life. There are 4 sub-tests: general information about speech, your reactions to stuttering, communication in daily situations, quality of life. Each one has a score from 1 to 5 with regard to impact (1 least, 5 most negative impact). These are combined to give a total impact score between 1 and 5, with 5 representing the highest negative impact on person's life. The change on the total impact score will be used. Changes are shown in the table below by comparison between the measurements at the three po

Pre

Group	Value	95% CI
Active tDCS and Fluency Training	2.48	± .61
Sham tDCS and Fluency Training	2.67	± .75

Post

Group	Value	95% CI
Active tDCS and Fluency Training	2.34	± .55
Sham tDCS and Fluency Training	2.56	± .78

Follow up

Group	Value	95% CI
Active tDCS and Fluency Training	2.35	± .57
Sham tDCS and Fluency Training	2.59	± .88

Adverse events — posted to ClinicalTrials.gov

Time frame: 6 weeks. Reporting threshold: 0%. Adverse-event reports describe events observed during the trial — not all are caused by the drug.

Active tDCS and Fluency Training

Serious: 0/12 (0%)

Deaths: 0/12

Sham tDCS and Fluency Training

Serious: 0/11 (0%)

Deaths: 0/11

Other adverse events (11 terms — click to expand)

Reaction	System	Active tDCS and Fluency Tr…	Sham tDCS and Fluency Trai…
Tingling	Skin and subcutaneous tissue disorders	—	—
Warm sensation	Skin and subcutaneous tissue disorders	—	—
Sleepiness	General disorders	—	—
Scalp pain	Skin and subcutaneous tissue disorders	—	—
Fatigue	General disorders	—	—
Trouble concentrating	General disorders	—	—
Headache	General disorders	—	—
Nervousness	General disorders	—	—
Neck pain	Musculoskeletal and connective tissue disorders	—	—
Changes in visual sensations	General disorders	—	—
Acute mood change	General disorders	—	—

Data from ClinicalTrials.gov NCT03437512 adverse events section.

Sponsor's own description

Research studies in stuttering have shown that activity patterns in certain brain areas differ in people who stutter compared to people who do not stutter when speaking. The purpose of this study is to investigate how mild, non-invasive brain stimulation applied consecutively for five days affects speech relevant brain areas, which may in turn affect speech fluency and speaking-related brain activity in people who stutter.

Publications & conference data

2 peer-reviewed publications reference this trial (live from Europe PMC):

1. Speech Fluency Improvement in Developmental Stuttering Using Non-invasive Brain Stimulation: Insights From Available Evidence.
   Busan P, Moret B, Masina F, Del Ben G, et al · · 2021 · cited 15× · PMID 34456692 · DOI 10.3389/fnhum.2021.662016
2. Differential contribution of working memory to auditory rhythm discrimination in stuttering and nonstuttering adults.
   Garnett EO, Smith T, Rann B, Mularoni N, et al · · 2025 · PMID 41366010 · DOI 10.1038/s41598-025-31490-4