Velopharyngeal Aerodynamics Following Bilateral Subthalamic
Nucleus Deep Brain Stimulation in Parkinson’s Disease

M Hammer, S Barlow, R Pahwa

The efficacy of bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) on velopharyngeal (VP) aerodynamics was studied in eighteen patients with idiopathic Parkinson’s disease (PD). Adequate VP closure during speech production depends on approximation of the velum with the lateral and posterior pharyngeal walls to an orifice area less than 5 mm². Individuals with PD often exhibit disorders in timing, extent and coordination of VP function. Measures were made of intraoral pressure (P_o), peak VP airflow (P-Flow), VP resistance (VPR) and estimates of VP area (VPA) to characterize VP function. Although not always positive, initial results reveal substantial reorganization of VP function in speech motor control. These data further support the notion that changes in motor drive associated with the hypokinetic dysarthria of PD and the treatment effect of DBS impose change in motor drive across multiple components of the vocal tract.