Using Non-invasive Brain Stimulation to Explore Potential Treatments to Reduce Speech Errors in Adults Who Stutter

The goal of this study is to find out whether a type of noninvasive brain stimulation can help reduce speech errors, such as repetitions, blocks, and prolongations, in people who stutter. This pilot study will help researchers design future treatments to see if targeting certain brain areas can improve speech fluency. The study will look at how people speak and behave during both speaking and non-speaking tasks before and after the brain stimulation. Participants will complete an online survey about 24 hours before coming to the clinic. The clinic visit will last about 3 hours and will include three phases. All parts of the study will be audio-recorded. 1. Pre-Testing: Participants will first complete a stuttering evaluation to determine whether they are typical speakers or have a mild, moderate, or severe stutter. Then, they will do several speaking and non-speaking tasks. 2. Brain Stimulation: Participants will receive a session of targeted noninvasive brain stimulation (HD-tDCS). 3. Post-Testing: After the brain stimulation, participants will repeat the same evaluation and tasks they completed during pre-testing. Brain stimulation description: HD-tDCS is a non-invasive technique that requires the placement of several sensors (metal electrodes) on a special cap and saline gel on your head. Very low levels of constant electrical current are delivered to specifically targeted areas of the brain via these electrodes. You may experience a slight feeling of dizziness when starting the stimulation. This occurs in a small number of subjects. This takes only a few seconds and does not affect balance after the stimulation has been completed. Several research centers have previously investigated the use of this device on healthy subjects and have found the device to be safe with no direct effect on the person's well-being. Following stimulation, participants will have the opportunity to rinse out residual gel from hair and scalp.