Bihemispheric Transcranial Direct Current Stimulation* on Speech Fluency

Not Applicable

Recruiting

• Conditions: Stuttering, Adult
• Interventions: Device: Transcranial direct current stimulation

• Registration Number: NCT06278233
• Lead Sponsor: Biruni University

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.

Detailed Description

Developmental stuttering is a fluency disorder that can negatively affect many aspects of an individual's life. Recent transcranial direct current stimulation (tDCS) studies with individuals with stuttering show that tDCS shows promise in increasing fluency when used in combination with situations that temporarily increase fluency. In this study, it was aimed to investigate the effect of bi-hemispheric tDCS on fluency in individuals with stuttering for 5 consecutive days. The hypothesis of the study is that bi-hemispheric stimulation, which includes anodal stimulation to the left hemisphere and cathodal stimulation to the right hemisphere, will be effective on reading and speech fluency when performed for 5 consecutive days. Thirty-six adults with developmental stuttering are expected to complete this double-blind, sham-controlled study. Participants will be divided into two groups by blocked randomization and one group will receive sham stimulation for 5 consecutive days and the other group will receive bihemispheric stimulation. Participants in the tDCS group will receive 20 minutes of tDCS stimulation accompanied by metronome-timed speech during the practice sessions. Reading and speaking fluency will be assessed immediately before, immediately after, and one week after the stimulation sessions. Data will be collected using the stuttering severity assessment instrument (SSI-4) Results will be compared both within and between groups in terms of percentage of stuttered syllables, stuttering severity, and evaluation of the speaker's experience of stuttering.

Study Timeline

• Status Verified: 2024-02
• Study Start: 2024-02
• Study First Submitted: 2024-02-08
• Study First Submitted QC: 2024-02-22
• Last Update Submitted: 2024-02-22
• Study First Posted: 2024-02-26
• Last Update Posted: 2024-02-26
• Primary Completion: 2024-06
• Study Completion: 2024-09

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 36

Inclusion Criteria

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

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Exclusion Criteria

• 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

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Transcranial direct current stimulation study arm	Transcranial direct current stimulation	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.

Primary Outcome Measures

Name	Time	Method
Disfluent 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.	change in % disfluent syllables from baseline

Secondary Outcome Measures

Name	Time	Method
The Overall Assessment of the Speaker's Experience of Stuttering (OASES) score	baseline, after the 5-day stimulation and at the 1-week post-intervention time point	The instrument, which requires approximately 20 min to complete, is organized into four sections: (a) General Information, (b) Reactions to Stuttering, (c) Communication in Daily Situations, and (d) Quality of Life. OASES consists of 100 items, each scored on a Likert scale ranging from 1 to 5. For each item on the OASES, response scales are that higher scores indicate a greater degree of negative impact associated with stuttering and lower scores indicate less negative impact. All impact scores range from a minimum score of 20 (if the speaker answers 1 for every item within a section) up to a maximum of 100 (if the speaker answers 5 for every item within the section).
Stuttering Severity Instrument- Fourth Edition (SSI-IV) score	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.	It measures stuttering severity in the following four areas of speech behavior: (1) frequency, (2) duration, (3) physical concomitants, and (4) naturalness of the individual's speech. Frequency is expressed in percent syllables stuttered and converted to scale scores of 2-18. Duration is timed to the nearest one tenth of a second and converted to scale scores of 2-18. The four types of Physical Concomitants (Distracting Sounds, Facial Grimaces, Head Movements, and Movements of the Extremities) are converted to scale scores of 0-20. Naturalness is ranked on a scale from 1 (Highly Natural Sound Speech) to 9 (Highly Unnatural Sound Speech). Overall naturalness is ranked at the discretion of the clinician. Scaled scores of Frequency, Duration, and Physical Concomitants are added together to derive a Total Score, Percentile Rank, and Severity Equivalent.

Trial Locations

Locations (1)

Biruni University; 🇹🇷 Istanbul, Zeytinburnu, Turkey