Subthalamic Nucleus Deep Brain Stimulation in Speech Study

Aim 1. Define the mechanistic role of STN in speech using direct intraoperative brain recordings. For the first time, we will define STN neuronal physiology for both speech and limb tasks. Through multichannel microelectrode recording (MER) during awake STN-DBS implantation surgery, we will test the hypothesis suggested by our pilot data that STN firing rate during speech will be significantly different from the firing rate during a limb motor task.

Aim 2. Advance understanding of speech outcomes associated with STN-DBS. Intelligibility will serve as the primary functional communication outcome, with communication participation as a secondary metric. Acoustic measures of articulation, phonatory-respiratory behavior and tempo-fluency will be obtained.

Aim 2A. Determine differential effects of DBS stimulation (ON vs. OFF) on speech outcomes. ON vs. OFF stimulation changes in acoustic measures of speech will be used to inform potential reasons for observed changes in intelligibility.

Aim 2B. Define longitudinal effects of STN-DBS on speech outcomes. Speech outcomes and limb measures obtained pre-surgery will be compared to those at 6 and 12 months post-surgery when DBS stimulation is ON. Change in communication participation also will be defined. The control group studied at similar time points will control for disease progression.

Aim 2C. Determine associations between acoustic measures and intelligibility in STN-DBS.

Aim 3. Explore factors associated with changes in intelligibility post STN-DBS. As initial endeavors to guide future studies, we will:

Aim 3A. Use our metrics from Aims 1 and 2 (e.g. disease-specific characteristics, microelectrode recording data, pre-operative intelligibility) to identify factors that predict intelligibility at 12 months following STN-DBS.

Aim 3B. Test the feasibility of manipulating DBS stimulation parameters to improve intelligibility in a subset of participants with DBS-induced intelligibility declines.