Bihemispheric Transcranial Direct Current Stimulation* on Speech Fluency

NCT06278233 | Completed Results

• 1 other identifier: 2023/85-70
• Study Type: interventional
• Target: 36
• Locations: 1 country
• Sites: 1

Brief Summary

It will be determined whether bihemispheric stimulation (anodal to the left IFG and cathodal to the right IFG) is used with fluency-facilitating conditions for 5 consecutive days in individuals with stuttering and whether there is a difference in terms of the effects seen in speech fluency compared to the sham condition.

Conditions

Stuttering, Adult

Keywords

stuttering; tDCS; non-invasive brain stimulation; speech therapy

Outcome Measures

Primary Outcomes (4)

• Stuttered Syllables in Passage Reading (Change in the Percentage of Stuttered Syllables After 5 Days of Intervention From Baseline)

  Percentage of syllables stuttered (%SS) was calculated as the number of stuttered syllables divided by the total number of syllables produced, multiplied by 100. Repetitions, prolongations, syllable repetitions, tense pauses and pre-speech sound blocking were defined as moments of disfluency. Whole-word and whole-phrase repetitions were included in the total syllable count but were not counted as stuttered syllables.Video recordings have been used in assessment procedures and pre-speech sound blocking identified by postural fixations. For both reading and speaking measures, the first 300 syllables were used for analysis (syllable count ranged from 139-490 syllables).

  immediately before and immediately after the stimulation on each day of the 5-day intervention, and at 1 week after the end of the intervention.

• Stuttered Syllables in Passage Reading (Change From Baseline in Percentage of Disfluent Syllables 1 Week After Intervention)

  Percentage of syllables stuttered (%SS) was calculated as the number of stuttered syllables divided by the total number of syllables produced, multiplied by 100. Repetitions, prolongations, syllable repetitions, tense pauses and pre-speech sound blocking were defined as moments of disfluency. Whole-word and whole-phrase repetitions were included in the total syllable count but were not counted as stuttered syllables.Video recordings have been used in assessment procedures and pre-speech sound blocking identified by postural fixations. For both reading and speaking measures, the first 300 syllables were used for analysis (syllable count ranged from 139-490 syllables).

  immediately before and immediately after the stimulation on each day of the 5-day intervention, and at 1 week after the end of the intervention.

• Stuttered Syllables in Conversation (Change in the Percentage of Stuttered Syllables After 5 Days of Intervention From Baseline)

  Percentage of syllables stuttered (%SS) was calculated as the number of stuttered syllables divided by the total number of syllables produced, multiplied by 100. Repetitions, prolongations, syllable repetitions, tense pauses and pre-speech sound blocking were defined as moments of disfluency. Whole-word and whole-phrase repetitions were included in the total syllable count but were not counted as stuttered syllables.Video recordings have been used in assessment procedures and pre-speech sound blocking identified by postural fixations. For both reading and speaking measures, the first 300 syllables were used for analysis (syllable count ranged from 139-490 syllables).

  immediately before and immediately after the stimulation on each day of the 5-day intervention, and at 1 week after the end of the intervention.

• Stuttered Syllables in Conversation (Change From Baseline in Percentage of Disfluent Syllables 1 Week After Intervention)

  Percentage of syllables stuttered (%SS) was calculated as the number of stuttered syllables divided by the total number of syllables produced, multiplied by 100. Repetitions, prolongations, syllable repetitions, tense pauses and pre-speech sound blocking were defined as moments of disfluency. Whole-word and whole-phrase repetitions were included in the total syllable count but were not counted as stuttered syllables.Video recordings have been used in assessment procedures and pre-speech sound blocking identified by postural fixations. For both reading and speaking measures, the first 300 syllables were used for analysis (syllable count ranged from 139-490 syllables).

  immediately before and immediately after the stimulation on each day of the 5-day intervention, and at 1 week after the end of the intervention.

Secondary Outcomes (4)

• Change in Stuttering Severity Instrument (SSI-IV) Scores After 5 Days of Intervention From Baseline

  immediately before and immediately after the stimulation on each day of the 5-day intervention, and at 1 week after the end of the intervention.

• Change From Baseline in Stuttering Severity Instrument (SSI-IV) Scores 1 Week After Intervention

  immediately before and immediately after the stimulation on each day of the 5-day intervention, and at 1 week after the end of the intervention.

• Change in The Overall Assessment of the Speaker's Experience of Stuttering (OASES) Scores After 5 Days of Intervention From Baseline

  baseline, after the 5-day stimulation and at the 1-week post-intervention time point

• Change From Baseline in The Overall Assessment of the Speaker's Experience of Stuttering (OASES) Scores 1 Week After Intervention

  baseline, after the 5-day stimulation and at the 1-week post-intervention time point

Study Arms (2)

Transcranial direct current stimulation study arm

EXPERIMENTAL

For bi-hemispheric stimulation, the anode will be placed at the intersection of F7 and FC5 and the cathode will be placed at the intersection of F8 and FC6. For all stimulations, the stimulation will be increased for 15 seconds at a dosage of 1 mA (milliampere) for the entire 20 minute session duration and decreased for 15 seconds at the end of the stimulation.

Device: Transcranial direct current stimulation

Sham stimulation study arm

NO INTERVENTION

In the sham condition, the same electrode placement will be used, during which the current will be increased for 15 seconds, kept at 1 mA for 15 seconds, decreased for 15 seconds and terminated, and the 20 minute session duration will be performed with 45 seconds of real stimulation accompanied by speech with a metronome.

Interventions

Transcranial direct current stimulation DEVICE

TDCS involves applying a weak electrical current across the head through electrodes placed on the scalp and modulating the resting membrane potential of neurons in the underlying cortex.

Transcranial direct current stimulation study arm

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• developmental stuttering
• age between 18 and 60 years
• right hand dominant

You may not qualify if:

• history of seizures, head trauma, hearing problems, cochlear implant, intracranial metal implantation, medications that affects the central nervous system, implanted neurostimulators, cardiac pacemakers, or medication infusion devices
• any speech and language disorder other than developmental stuttering
• neurological or psychiatric disorders, brain surgery, tumours, neurodevelopmental disorders, or attention deficit hyperactivity disorder

Sponsors & Collaborators

• Biruni University: lead

Study Sites (1)

Biruni University

Istanbul, Zeytinburnu, 34015, Turkey (Türkiye)

Location

Related Publications (3)

• Chesters J, Mottonen R, Watkins KE. Transcranial direct current stimulation over left inferior frontal cortex improves speech fluency in adults who stutter. Brain. 2018 Apr 1;141(4):1161-1171. doi: 10.1093/brain/awy011.

  PMID: 29394325 RESULT

• Yada Y, Tomisato S, Hashimoto RI. Online cathodal transcranial direct current stimulation to the right homologue of Broca's area improves speech fluency in people who stutter. Psychiatry Clin Neurosci. 2019 Feb;73(2):63-69. doi: 10.1111/pcn.12796. Epub 2018 Dec 11.

  PMID: 30379387 RESULT

• Garnett EO, Chow HM, Choo AL, Chang SE. Stuttering Severity Modulates Effects of Non-invasive Brain Stimulation in Adults Who Stutter. Front Hum Neurosci. 2019 Nov 21;13:411. doi: 10.3389/fnhum.2019.00411. eCollection 2019.

  PMID: 31824276 RESULT

MeSH Terms

Conditions

Stuttering; Communication Disorders

Interventions

Transcranial Direct Current Stimulation

Condition Hierarchy (Ancestors)

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

Intervention Hierarchy (Ancestors)

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

Results Point of Contact

• Title: Slp. Feyzanur Ocak
• Organization: Üsküdar University

feyzanurocak@gmail.com

05313606661

Study Officials

• Feyzanur Ocak, Slp

  Atlas University

  PRINCIPAL INVESTIGATOR

• Talat Bulut, Asst. prof.

  Medipol University

  STUDY CHAIR

• Çağdaş Karsan, Asst. prof.

  Biruni University

  STUDY DIRECTOR

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Masking Details: One researcher not involved in any aspect of the study will randomize participants to the sham and tDCS study arms using blocked randomization. To ensure blinding, one researcher will record the administration of the tDCS and assessments, while independent speech-language pathologists will monitor the assessment recordings and score the test items.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: speech therapist

Model Details: In this study, a double-blind, randomized controlled research design from experimental research methods will be applied.

Study Record Dates

• First Submitted: February 8, 2024
• First Posted: February 26, 2024
• Study Start: January 23, 2024
• Primary Completion: June 30, 2024
• Study Completion: July 15, 2024
• Last Updated: March 20, 2026
• Results First Posted: March 20, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will share
• Time Frame: during submission of article
• Access Criteria: public and no criteria

Locations

TU (1)