Deep Brain Stimulation in Laryngeal Dystonia and Voice Tremor

PROJECT SUMMARY / ABSTRACT Loss of voice control, which is critical for conveying effective spoken communication, is often a significant feature in patients with movement disorders, such as dystonia and essential tremor. Voice dysfunction, however, has been overshadowed clinically by a focus on limb motor symptoms. For example, deep brain stimulation (DBS) effectively reduces limb dystonia and tremor in these patients, but the modulation of voice symptoms by DBS has been vastly understudied. It is assumed that the production and modulation of voice are regulated by the basal ganglia-thalamo-cortical network in a loop architecture that is common to all motor behaviors. There is, however, little empirical data to inform our specific understanding of how voice function is encoded in basal ganglia-thalamo-cortical interactions. The overall goal of this Project is to use a combination of invasive and non-invasive human neuroscience to improve our understanding of the incidence and neural correlates of neurological voice disorders (laryngeal dystonia and voice tremor) in patients with isolated dystonia and essential tremor undergoing DBS surgery. We will use simultaneous electrocorticography (ECoG) and subcortical activity recording in dystonia and tremor patients who are awake and speaking during DBS implantation surgery. We will supplement these data with non- invasive, multimodal scalp magneto/electroencephalography (M/EEG) and functional MRI (fMRI) recordings before DBS surgery and longitudinal M/EEG recordings within one year after surgery to enhance our understanding of DBS-induced neural network modulation relevant to voice motor symptoms in dystonia and tremor patients. This work will be facilitated by the fact that all participating Center sites already use the same equipment and techniques for DBS implantation and will follow standardized experimental protocols. The disorder-specific intracranial neurophysiological signatures will be correlated with non-invasive imaging findings, stimulation location defined connectivity maps, and voice outcomes. The results of this Project will inform the development of strategies for closed-loop brain stimulation specifically to treat neurological voice dysfunction that can be tested in a subsequent clinical trial.