Clinical Research Directory

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.

Propranolol in Primary Progressive Aphasia

The purpose of this study is to find out how the language of people with Primary Progressive Aphasia is affected by Propranolol. Propranolol is not FDA approved for the treatment of Primary Progressive Aphasia. Propranolol is FDA approved for the treatment of heart conditions such as blood pressure. This research is being done because there are currently no drug treatment options for language impairments and anxiety often experienced by people with Primary Progressive Aphasia.

Effects of Transcranial Direct Current Stimulation (tDCS) on Inhibition and Brain Function in Primary Progressive Aphasia

Primary progressive aphasia (PPA) is a focal dementia characterized by primary impairment of language abilities and functional disturbances associated with language. Although PPA is a progressive disorder, new techniques are being proposed to try to activate parts of the brain previously thought to be potentially inactive, due to the possibility of "neuroplasticity". This concept refers to our brain's modularity and learning potential. Transcranial direct current stimulation is a powerful neuromodulatory technique, in which a small current is applied to the participant's scalp through the targeted positioning of an anode and a cathode. The positive or anodal stimulation of tDCS is supposed to increase neuronal activity under the electrode, while cathodal stimulation is supposed to do the opposite. This project will provide new insights into the nature of the neural activity underlying executive functions in people with primary progressive aphasia compared to those without. The investigators expect to find reduced amplitude of electrophysiological responses and lower accuracy in people with primary progressive aphasia compared with healthy controls. Given the results of previous studies showing the efficacy of tDCS protocols in the treatment of aphasia, the investigators might expect them to improve executive functions. If so, the investigators expect significantly greater electrophysiological responses after stimulation sessions compared with sham conditions. This project is of great clinical relevance. This research will improve current therapeutic protocols used in the treatment of PPA by providing critical findings on whether and how the use of tDCS improves executive functions. Crucially, the research will advance knowledge of executive function decline as a sensitive marker of PPA, informing us about the possibility of early detection of this disorder. At the same time, the investigators will analyze the possibility of controlling symptomatological evolution via the analysis of acoustic and vocal markers. This will enable us to observe the evolution of sensory markers such as acoustic markers according to symptomatological evolution. This will enable us to check whether acoustic markers correlate with the patient's level of symptomatological impairment and/or pathological physiological data.