Brain Stimulation for Speech Disorders

This trial explores how different brain regions collaborate to control speech, focusing on individuals who stutter or have dyslexia. Participants will perform speech tasks where researchers alter the sounds they hear or their jaw movements to study speech motor skills. Some sessions will include noninvasive brain stimulation, such as reflexive somatosensory perturbation and various forms of auditory feedback perturbation, to assess its impact on speech control. Suitable candidates have a history of stuttering or dyslexia, are native English speakers, and have no major neurological issues. The findings aim to explain variations in speech abilities and how brain differences might contribute to stuttering and dyslexia. As an unphased trial, this study offers a unique opportunity to contribute to groundbreaking research on speech control and brain function.

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators for clarification.

Previous studies indicate that participants have generally handled different methods of feedback changes well. Research shows that reflexive somatosensory feedback changes use safe, non-invasive techniques to study how the brain reacts to changes in speech-related sensory feedback. These studies do not report significant negative effects, suggesting that the approach is well-tolerated.

Similarly, studies on sustained F0 and F1 auditory feedback changes have shown these techniques to be safe. These methods alter how participants hear their own voices, helping researchers understand how people adjust their speech. The findings suggest that this practice is generally safe without serious side effects.

For unpredictable auditory feedback changes, research shows that it safely alters the timing of audio feedback to study how people correct their speech. This technique is also reported as well-tolerated with no major negative effects.

Researchers are excited about these brain stimulation techniques for speech disorders because they explore innovative ways to enhance speech motor control. Unlike traditional speech therapy that focuses on behavioral interventions, these treatments use transcranial current stimulation (tCS) to target specific brain regions, potentially altering neural activity directly. The unique aspect of this approach is its ability to apply stimulation to areas like the ventral premotor cortex (vPMC) and the posterior superior temporal gyrus (pSTG), which are crucial for speech processing. This could lead to more effective and faster improvements in speech abilities compared to conventional methods. Additionally, the use of both real and sham stimulation helps researchers understand the true impact of the treatment on the brain and speech function.

This trial will compare different brain stimulation techniques to understand their effects on speech control. Participants in one arm will receive transcranial current stimulation (tCS) targeting the left and right ventral premotor cortex (vPMC), while those in another arm will receive tCS targeting the posterior superior temporal gyrus (pSTG) and ventral somatosensory cortex (vSSC). Research has shown that different types of feedback can influence speech control. Reflexive changes in the sensation of movements, such as those of the jaw and lips, affect how the brain manages speech. Studies have found that this helps in understanding voice control. Changes in auditory feedback, like pitch and tone, are crucial for learning and maintaining clear speech, especially for children and adults with speech disorders. When people hear unexpected sounds, it allows researchers to assess their ability to adjust speech. This understanding can enhance the management of speech disorders like stuttering by focusing on specific brain areas.¹²⁵⁶⁷