Overview

The purpose of this study is to collect preliminary data on the efficacy of transcranial direct current stimulation (tDCS) combined with traditional behavioral techniques to reduce stuttering severity and negative impact in adults who stutter. The study also aims to explore neuroplastic changes (i.e., regional activation and functional connectivity) resulting from combined tDCS + speech therapy.

Eligibility

Inclusion Criteria:

1. Adults aged 18 to 65 years.
2. Diagnosis of developmental stuttering, verified by a licensed speech-language pathologist.
3. Mild-to-moderate or greater stuttering severity, defined as a score of 20 or higher on the Stuttering Severity Instrument-Fourth Edition (SSI-4).
4. English as a primary language.
5. Right-handedness (to minimize variability in neural lateralization).
6. Willing and able to attend all study sessions and follow study procedures.

Exclusion Criteria:

1. Have a history of neurological, psychiatric, or medical conditions that are contraindicated for tDCS.
2. Are currently taking medications known to affect cortical excitability.
3. Have a history of seizures or epilepsy.
4. Are pregnant or planning to become pregnant during the study period.
5. Have metal implants in the head (excluding dental work) or other contraindications to electrical brain stimulation.
6. Any skin disorder or skin sensitive area near stimulation locations.