Clinical Research Directory

Investigating Individual Differences in Speech Motor Skills in Neurotypical Speakers and Persons With Disordered Speech

This study aims to understand how people use different types of feedback to control their speech. When an individual speaks, the brain relies on several systems at the same time, such as sensory systems that monitor an individuals own voice and the movements of their speech muscles, and a motor system that builds and reads out learned motor patterns. The investigators are studying how these systems work together and how they differ across individuals. Investigators will test 90 adults between 18 and 50 years old, including people who stutter, people with dyslexia, and people with typical speech and reading development. Participants will complete several short speech tasks in which the sounds they hear or the movements of their jaw or larynx are briefly changed. These responses will be used to measure each person's speech motor skills and to estimate the settings of a computer model called "SimpleDIVA," which simulates how the brain controls speech. Participants will also complete an MRI scan so investigators can measure the structure and connectivity of different brain regions. These measures will help investigators understand how individual differences in the brain relate to the speech motor control skills we observe. Participants will also complete sessions with noninvasive brain stimulation (transcranial current stimulation, or tCS) to examine how stimulation of specific areas of the brain affects responses during the speech tasks. The knowledge gained from this study will help researchers understand why speech motor skills vary across people and how differences in neural function may contribute to conditions such as stuttering and dyslexia.

Organization and Development of Motor Cortical Circuits for Speech Production in Stuttering

The overall objective of this study is to examine inter effector areas (IEAs) activity and functional connectivity during continuous speech production in stuttering adults.

Investigating Speech Sequencing in Neurotypical Speakers and Persons With Disordered Speech

Persistent developmental stuttering affects more than three million people in the United States, and it can have profound adverse effects on quality of life. Despite its prevalence and negative impact, stuttering has resisted explanation and effective treatment, due in large part to a poor understanding of the neural processing impairments underlying the disorder. The overall goal of this study is to improve understanding of the brain mechanisms involved in speech motor planning and how these are disrupted in neurogenic speech disorders, like stuttering. The investigators will do this through an integrated combination of experiments that involve speech production, functional MRI, and non-invasive brain stimulation. The study is designed to test hypotheses regarding the brain processes involved in learning and initiating new speech sound sequences and how those processes compare in persons with persistent developmental stuttering and those with typical speech development. These processes will be studied in both adults and children. Additionally, these processes will be investigated in patients with neurodegenerative speech disorders (primary progressive aphasia) to further inform the investigators understanding of the neural mechanisms that support speech motor sequence learning. Together these experiments will result in an improved account of the brain mechanisms underlying speech production in fluent speakers and individuals who stutter, thereby paving the way for the development of new therapies and technologies for addressing this disorder.

Transcranial Alternating Current Stimulation (tACS) in Stuttering

The purpose of this study is to investigate how mild, noninvasive electrical brain stimulation affects speech relevant brain areas, which may in turn affect speech fluency and speaking-related brain activity in people that stutter. The long-term goal of this study is to test the therapeutic potential of transcranial alternating current stimulation (tACS) for the treatment of stuttering. The study team hypothesizes that if stuttering involves impaired initiation of motor programs, delta-tuned tACS will strengthen communication between brain regions and decrease stuttering. Therefore, delta-tuned sensorimotor tACS will be paired with fluency-induced speech (choral reading), which is hypothesized to decrease stuttering via improved auditory motor integration.

The Development of Stuttering in Young Children

The goal of this longitudinal research is to learn why some children "grow out" of stuttering, while others persist. Children who do and do not stutter aged 3-6 years are eligible to participate in our study. During the study, children's speech and language abilities will be assessed with standardized assessments, and they complete several child-friendly experiments. During these experiments, brain activity will be recorded using specialized caps while children describe pictures, children will speak in two virtual-reality scenarios, and produce speech while keeping to a beat.

Auditory Prediction and Error Evaluation in the Speech of Individuals Who Stutter

Stuttering negatively impacts communication and reduces the overall quality of life and well-being of individuals who stutter. This study will provide a strong foundation for developing neural and behavioral interventions for stuttering. Participants will be asked to name pictures, read words/sentences silently or aloud, and listen to speech and nonspeech sounds while their speech, muscle, and brain signals are collected. Some participants may also receive brain stimulation while reading and speaking.

Exploring the Nature, Assessment and Treatment of Stuttering

The purposes of this study are to 1) investigate potential speech, language, and psychosocial contributions to the experience of stuttering in monolingual and multilingual speakers, and to 2) evaluate interdisciplinary, telehealth, and speech-language pathology treatment methods and clinical training specific to fluency disorders.