Shaping Motor Neural Functioning of Developmental Stuttering to Improve Fluency

Study Overview
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Brief Summary
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Developmental stuttering (DS) is a motor/speech disorder, characterized by specific alterations in the functioning of brain circuits. Non-invasive brain stimulation may be useful to shape the altered functioning and connectivity of these systems. As a consequence, this project aims to expand the neurophysiological understanding of DS, evaluating effects of transcranial electrical stimulation (tES) on speech fluency and brain functioning of adults with persistent DS. This project will provide high-impact insights into the functioning of DS neural system, also proposing innovative and/or personalized rehabilitation.

Detailed Description
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Investigators will evaluate the effect of different tES protocols targeting motor associative regions (about 10 consecutive stimulation sessions, in different days; tES will be compared to sham stimulation), in association with canonical speech therapy. About 30 right-handed adults with idiopathic and persistent DS since childhood will be recruited (age 18-59 years; please see below for inlusion/exclusion criteria). Participants will be subdivided in three groups (in association to speech therapy): two groups will undergo transcranial random noise stimulation or transcranial direct current stimulation, while the third group will undergo sham (placebo) stimulation . Effects will be assessed by measuring stuttering severity (i.e. objective evaluation of stuttering), behavioral/cognitive scales (i.e. subjective evaluation of stuttering), as well as a series of neurophysiological indexes useful to evaluate brain functioning and connectivity (e.g. TMS[transcranial magnetic stimulation]-induced motor/evoked potentials and EEG brain activity). Evaluations will be realized before the start of the tES protocols, as well as at the end of the cycles. Follow-up evaluations (starting from about 6 weeks after completion of stimulation sessions) are also foreseen after the end of the treatments.

Official Title
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The Treatment of Persistent Developmental Stuttering: Shaping of Motor Neural Functioning to Improve Fluency

Conditions
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Stuttering

Intervention / Treatment
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* Device: transcranial Electrical Stimulation
* Behavioral: Speech Therapy


Participation Criteria
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Eligibility Criteria
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(main) Inclusion Criteria: -Right-handed adults with idiopathic, persistent DS since childhood (main) Exclusion Criteria: Contraindications to non-invasive brain stimulation; Currently assumption of drugs acting on the Central Nervous System; Presence of overt neurological/psychiatric/medical conditions or overt comorbidities (e.g. obsessive-compulsive disorder).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 59 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Factorial Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Transcranial Random Noise Stimulation<br>Transcranial Random Noise Stimulation (1.5 mA, High Frequency) administered by using surface scalp electrodes (20 minutes, initial part of the session) in correspondence of associative motor regions, during speech therapy sessions (45 minutes). | Device: transcranial Electrical Stimulation<br>* transcranial Random Noise Stimulation, transcranial Direct Current Stimulation, or Sham are administered (by means of surface electrodes) on associative motor regions during speech therapy sessions (20 minutes, in the initial part of the sessions; 1.5 mA).<br>Behavioral: Speech Therapy<br>* Speech Therapy is associated to transcranial electrical stimulation or sham, during stimulation sessions. Total duration of the single session: 45 minutes<br>|
| Experimental: Transcranial Direct Current Stimulation<br>Transcranial Direct Current Stimulation (1.5 mA, anodal) administered by using surface scalp electrodes (20 minutes, initial part of the session) in correspondence of associative motor regions, during speech therapy sessions (45 minutes). | Device: transcranial Electrical Stimulation<br>* transcranial Random Noise Stimulation, transcranial Direct Current Stimulation, or Sham are administered (by means of surface electrodes) on associative motor regions during speech therapy sessions (20 minutes, in the initial part of the sessions; 1.5 mA).<br>Behavioral: Speech Therapy<br>* Speech Therapy is associated to transcranial electrical stimulation or sham, during stimulation sessions. Total duration of the single session: 45 minutes<br>|
| Sham Comparator: Sham Direct Current/Random Noise Stimulation<br>Sham stimulation administered by using surface scalp electrodes (20 minutes, initial part of the session) in correspondence of associative motor regions, during speech therapy sessions (45 minutes). | Device: transcranial Electrical Stimulation<br>* transcranial Random Noise Stimulation, transcranial Direct Current Stimulation, or Sham are administered (by means of surface electrodes) on associative motor regions during speech therapy sessions (20 minutes, in the initial part of the sessions; 1.5 mA).<br>Behavioral: Speech Therapy<br>* Speech Therapy is associated to transcranial electrical stimulation or sham, during stimulation sessions. Total duration of the single session: 45 minutes<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Speech Fluency and Stuttering Severity (change from baseline) | Utilization of (objective) scales to evaluate stuttering severity and speech fluency (Stuttering Severity Instrument [range 0-56; higher values indicate higher numbers of dysfluencies]) | Evaluated immediately after the end of treatments | 
| TMS-induced (Motor) Evoked Potentials (change from baseline) | Utilization of Transcranial Magnetic Stimulation to evaluate excitability (and reactivity) of motor cortex | Evaluated immediately after the end of treatments | 
| EEG (change from baseline) | Utilization of EEG to evaluate brain functioning and brain connectivity (delta, theta, alpha, beta, and gamma activity) | Evaluated immediately after the end of treatments | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Stuttering Severity (subjective perception) (change from baseline) | Utilization of (subjective) scales to evaluate stuttering severity/speech fluency (e.g. Premonitory Awareness in Stuttering Scale [range 0-42; higher values indicate higher invasiveness of stuttering with respect to quality of life]) | Evaluated immediately after the end of treatments | 
| Stuttering Severity (subjective perception) (change from baseline) | Utilization of (subjective) scales to evaluate stuttering severity/speech fluency (e.g. Premonitory Awareness in Stuttering Scale [range 0-42; higher values indicate higher invasiveness of stuttering with respect to quality of life]) | Evaluated about 6 weeks after the end of treatments | 
| Speech Fluency and Stuttering Severity (change from baseline) | Utilization of (objective) scales to evaluate stuttering severity and speech fluency (Stuttering Severity Instrument [range 0-56; higher values indicate higher numbers of dysfluencies]) | Evaluated about 6 weeks after the end of treatments | 
| TMS-induced (Motor) Evoked Potentials (change from baseline) | Utilization of Transcranial Magnetic Stimulation to evaluate excitability (and reactivity) of motor cortex | Evaluated about 6 weeks after the end of treatments | 
| EEG (change from baseline) | Utilization of EEG to evaluate brain functioning and brain connectivity (delta, theta, alpha, beta, and gamma activity) | Evaluated about 6 weeks after the end of treatments | 
| Cognitive/behavioral indexes (associated with stuttering) (change from baseline) | Utilization of (subjective) scales to evaluate cognitive/behavioral reactions (e.g. Beck Depression Inventory [range 0-63; higher values indicate higher presence of depressive symptoms]) | Evaluated immediately after the end of treatments | 
| Cognitive/behavioral indexes (associated with stuttering) (change from baseline) | Utilization of (subjective) scales to evaluate cognitive/behavioral reactions (e.g. Beck Depression Inventory [range 0-63; higher values indicate higher presence of depressive symptoms]) | Evaluated about 6 weeks after the end of treatments | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Developmental Stuttering, Neuromodulation, transcranial Electrical Stimulation, Speech Fluency, Motor Networks