Enhancing Speech Fluency With Non-invasive Brain Stimulation in Developmental Stuttering

Study Overview
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Brief Summary
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This study aims to test whether the addition of transcranial direct current stimulation (TDCS) to speech fluency training results in improvements in speech fluency in adults with developmental stuttering. Half of the participants will receive anodal TDCS on five consecutive days, the other half will receive a sham stimulation for the same amount of time.

Detailed Description
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Studies using TDCS have shown improvements in motor performance, and in expressive language skills in clinical and healthy populations. The benefits of single sessions of TDCS are short-lived. However, stimulation over multiple sessions can increase and prolong learning effects that can persist for several weeks after the end of the stimulation period. We aim to target left hemisphere frontal regions involved in speech production with TDCS, and to pair this stimulation with speech fluency training.

Official Title
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Enhancing Speech Fluency With Non-invasive Brain Stimulation in Developmental Stuttering

Conditions
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Stuttering, Fluency Disorders, Speech Disorders

Intervention / Treatment
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* Device: Anodal TDCS
* Behavioral: Fluency Training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Native speaker of English. Right handed. Participant has moderate to severe Developmental Stuttering (Stammering) Exclusion Criteria: Speech, language or communication disorder other than Developmental Stuttering. Sensory impairment (hearing loss or visual impairment) History of drug abuse. History of seizures History of a neurological or psychiatric illness. History of neurosurgical procedure. Currently taking certain prescription medications such as anti-depressants and anti-malarial medication (as these may lower the seizure threshold)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Anodal TDCS<br>Participants will receive anodal TDCS over the left inferior frontal cortex. TDCS will be delivered at 1milliampere (mA) intensity for 20 minutes during speech fluency training (5 consecutive days). | Device: Anodal TDCS<br>* 20 minutes 1mA anodal stimulation to left inferior frontal cortex. Cathode positioned on right supra-orbital ridge.<br>Behavioral: Fluency Training<br>* Speech tasks will be completed using fluency-enhancing techniques: metronome-timed speech and auditory choral speech.<br>|
| Sham Comparator: Sham TDCS<br>Participants will receive sham TDCS over the left inferior frontal cortex. Sham stimulation will involve 30 seconds stimulation at the beginning of the 20 minutes of speech fluency training (5 consecutive days). | Behavioral: Fluency Training<br>* Speech tasks will be completed using fluency-enhancing techniques: metronome-timed speech and auditory choral speech.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline proportion of stuttering in speech sample | Quantitative measurement of stuttering | 1 week post-treatment | 
| Change from baseline proportion of stuttering in speech sample | Quantitative measurement of stuttering | 6 weeks post-treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline on the Stuttering Severity Instrument version 4 (SSI-4) | Standardised assessment of frequency and duration of stuttering and associated physical concomitants | 1 week post-treatment | 
| Change from baseline on the Stuttering Severity Instrument version 4 (SSI-4) | Standardised assessment of frequency and duration of stuttering and associated physical concomitants | 6 weeks post-treatment | 
| Change from baseline on Overall Assessment of Speaker's Experience of Stuttering (OASES) | Standardised assessment of the functional impact of stuttering on a person's life | 6 weeks post-treatment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Stammering, Brain stimulation