Laryngeal Engagement 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 the aerodynamics of laryngeal engagement was studied in nineteen patients with idiopathic Parkinson’s disease (PD). Laryngeal engagement (LE) during spoken production of a consonant-vowel syllable (e.g. /pa/) is defined as the transition from the plosive burst-release of the consonant to the onset of voicing in the vowel. Intrinsic laryngeal muscle activity responsible for LE consists of relative quiescence of the muscles of abduction, and contraction of the muscles of adduction resulting in approximation of the vocal folds at the midline above the respiratory airstream, and subsequent vocal fold oscillation in response to positive subglottal air pressure (P_s). Patients with PD often exhibit impairment in the alternation between phonatory onset and offset during connected speech and suffer from increased effort required for speech communication. Although not always positive, initial results reveal substantial reorganization of laryngeal and respiratory subsystems in speech motor control. Correlation analyses 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.