JMIR Publications

ABSTRACT

Background:

Stuttering is a complex speech disorder that affects speech fluency. Recently it has been shown that non-invasive brain stimulation may be useful to enhance the results of fluency interventions in adults who stutter. Delayed Auditory Feedback (DAF) is a method to enhance speech fluency in individuals who stutter. Adjunctive interventions are warranted to enhance the efficacy of this intervention.

Objective:

In the present study, we hypothesize that stutterers have pathological activation patterns in the primary and secondary auditory areas. Consequently, stimulation of respective areas might be promising as an adjunctive method to fluency training via DAF to enhance speech therapy success in stuttering individuals. We will systematically test this hypothesis in the present project.

Methods:

This study is designed as randomized, double-blind, sham-controlled clinical trial. All participants will receive DAF as intervention. The intervention group receives additionally real tDCS, while the control group is exposed to sham tDCS. The assignment of the participants to one of these groups will be randomized.

Results:

Before starting the treatment program, two pre-intervention assessments will be conducted to determine the severity of stuttering. Once these assessments are completed, each subject will participate in six intervention sessions. Post-intervention assessments will be carried out immediately and one week after the last intervention session. Afterwards, to explore long-term stability of the treatment results, the outcome parameters will be obtained in follow-up assessments six weeks after the treatment. As a primary outcome measurement, the percentage of stuttered syllables (SS %) will be calculated in pre, post, and follow-up assessments and the secondary outcomes will be the scores of SSI-4 and OASES questionnaires.

Conclusions:

We anticipate that this study will show an adjunctive effect of tDCS, when combined with DAF, on stuttering. This should include not only a reduction of the percentage of stuttered syllables, but also improved physical behavior and quality of life in adults who stutter. Clinical Trial: This trial is registered in ClinicalTrial.gov before recruiting the subjects. The registration number is NCT03990168 and the date of registration is June 18, 2019.