title: Subthalamic Stimulation Reduces Vowel Space at the Initiation of Sustained Production: Implications for Articulatory Motor Control in Parkinson's Disease.
abstract: Stimulation of the subthalamic nuclei (STN) is an effective treatment for Parkinson's disease, but complaints of speech difficulties after surgery have been difficult to quantify. Speech measures do not convincingly account for such reports.
  
  
  
  This study examined STN stimulation effects on vowel production, in order to probe whether DBS affects articulatory posturing. The objective was to compare positioning during the initiation phase with the steady prolongation phase by measuring vowel spaces for three "corner" vowels at these two time frames.
  
  
  
  Vowel space was measured over the initial 0.25 sec of sustained productions of high front (/i/), high back (/u/) and low vowels (/a/), and again during a 2 sec segment at the midpoint. Eight right-handed male subjects with bilateral STN stimulation and seven age-matched male controls were studied based on their participation in a larger study that included functional imaging. Mean values: age = 57±4.6 yrs; PD duration = 12.3±2.7 yrs; duration of DBS = 25.6±21.2 mos, and UPDRS III speech score = 1.6±0.7. STN subjects were studied off medication at their therapeutic DBS settings and again with their stimulators off, counter-balanced order.
  
  
  
  Vowel space was larger in the initiation phase compared to the midpoint for both the control and the STN subjects off stimulation. With stimulation on, however, the initial vowel space was significantly reduced to the area measured at the mid-point. For the three vowels, the acoustics were differentially affected, in accordance with expected effects of front versus back position in the vocal tract.
  
  
  
  STN stimulation appears to constrain initial articulatory gestures for vowel production, raising the possibility that articulatory positions normally used in speech are similarly constrained.
authors.affiliation: Brain and Behavior Laboratory, Geriatrics Division, The Nathan Kline Institute, Orangeburg, NY, USA.|Department of Psychiatry, New York University Langone School of Medicine, New York, NY, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Sidtis
authors.affiliation: Brain and Behavior Laboratory, Geriatrics Division, The Nathan Kline Institute, Orangeburg, NY, USA.
authors.forename: Amy G
authors.initials: AG
authors.lastname: Alken
authors.affiliation: Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
authors.forename: Michele
authors.initials: M
authors.lastname: Tagliati
authors.affiliation: Neurosurgery, Department of Surgery, Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors.forename: Ron
authors.initials: R
authors.lastname: Alterman
authors.affiliation: Brain and Behavior Laboratory, Geriatrics Division, The Nathan Kline Institute, Orangeburg, NY, USA.|Department of Communicative Sciences and Disorders, NYU Steinhardt School of Culture, Education, and Human Development, New York, NY, USA.
authors.forename: Diana
authors.initials: D
authors.lastname: Van Lancker Sidtis
mesh_terms: D046690:Deep Brain Stimulation / Q000009:adverse effects*; D005260:Female; D005868:Gestures; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology* / Q000523:psychology; D013060:Speech; D013068:Speech Production Measurement; D020531:Subthalamic Nucleus / Q000503:physiopathology*
keywords: Deep brain stimulation; Parkinson’s disease; speech; subthalamic nucleus; vowels