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.
Must be 22 years old or older
May be bi/multilingual but must speak English as dominant language.
Must be diagnosed or suspected of developmental stuttering disorder. Participants will be administered the Stuttering Severity Instrument 4 and categorized as typical speakers or mild, moderate, or severe stutterers.
Must be able to attend the session at the physical location within the clinic
Patients with preexisting speech/language disorders or previously diagnosed neurological disorders (including but not limited to apraxia of speech, cerebral palsy, dysarthria, tourettes, or any other neurological/motor condition) that affect speech/language (except stuttering) are excluded to minimize the interference of atypical brain activity.
Participants who have acquired or neurogenic stuttering (stuttering resulting from a brain injury) are excluded, as this study focuses exclusively on the effects of developmental stuttering.
Participants with a history of seizures
Participants with unexplained episodes of loss of consciousness, since such condition could be related with brain alterations or epilepsy
Parallel
High - Definition Transcranial Direct Current Stimulation
DeviceHD-tDCS protocol for LIFG group is as follows: A single 20-minute session with one anode at F7 at 1 mA and four 0.25 mA cathodes at T7, FP1, AF3, FC5 at 0.25 mA HD-tDCS protocol for the Pre-SMA group is as follows: A single 20-minute session with one anode 1mA at Fz 1 mA and four 0.25 mA cathodes at FP1, FP2, F7, F8
Stuttering Severity Instrument - 4
Stuttering Severity Instrument-Fourth Edition (SSI-4) is a reliable and valid norm-referenced stuttering assessment that can be used for both clinical and research purposes. It measures stuttering severity in both children and adults in the four areas of speech behavior: frequency duration physical concomitants naturalness of the individual's speech. The SSI-4 scores stuttering severity by combining measures of frequency (% syllables stuttered), duration (length of longest stutters), and physical concomitants (secondary behaviors) into a total score, which is then converted to a percentile rank and severity level (very mild to very severe) using age-specific standards. Higher percentile scores indicate more severe stuttering, with ranges like 1-4% being very mild and 96-99% very severe.
Predictive Naming Task
Participants are instructed to name images on a screen, given phrases that indicate high or low predictability for the target word. Task is measured by accuracy (number of correct answers) and participant response time.
Overall Assessment of the Speaker's Experience of Stuttering
The Overall Assessment of the Speaker's Experience of Stuttering (OASES) gives clinicians and researchers an impact rating and impact score, which reflect the degree of adverse impact a speaker experiences due to stuttering. The impact score combines information about (a) the speaker's perceptions about stuttering; (b) the negative affective (feelings), behavioral (actions), and cognitive (thoughts) reactions that the speaker has to stuttering; (c) the functional communication difficulties a speaker may have in different speaking environments; and (d) the impact of stuttering on the speaker's overall quality of life. The OASES is the only published tool that specifically examines Quality of Life in people who stutter. The OASES score reflects the impact of stuttering on a person's life, using a 1-5 rating scale where higher scores indicate a more severe impact, categorized into mild, mild-to-moderate, moderate, moderate-to-severe, and severe levels.
Button push Go/NoGo task
Participants are instructed to press a button when category A (objects) is presented on the screen, but not to push when category B (animals) is shown. Task is measured by accuracy (number of correct answers) and participant response time.
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