title: The effect of deep brain stimulation on the speech motor system.
abstract: OBJECTIVE
  Chronic deep brain stimulation of the nucleus ventralis intermedius is an effective treatment for individuals with medication-resistant essential tremor. However, these individuals report that stimulation has a deleterious effect on their speech. The present study investigates one important factor leading to these effects: the coordination of oral and glottal articulation.
  
  
  METHODS
  Sixteen native-speaking German adults with essential tremor, between 26 and 86 years old, with and without chronic deep brain stimulation of the nucleus ventralis intermedius and 12 healthy, age-matched subjects were recorded performing a fast syllable repetition task (/papapa/, /tatata/, /kakaka/). Syllable duration and voicing-to-syllable ratio as well as parameters related directly to consonant production, voicing during constriction, and frication during constriction were measured.
  
  
  RESULTS
  Voicing during constriction was greater in subjects with essential tremor than in controls, indicating a perseveration of voicing into the voiceless consonant. Stimulation led to fewer voiceless intervals (voicing-to-syllable ratio), indicating a reduced degree of glottal abduction during the entire syllable cycle. Stimulation also induced incomplete oral closures (frication during constriction), indicating imprecise oral articulation.
  
  
  CONCLUSIONS
  The detrimental effect of stimulation on the speech motor system can be quantified using acoustic measures at the subsyllabic level.
authors.forename: Doris
authors.initials: D
authors.lastname: Mücke
authors.forename: Johannes
authors.initials: J
authors.lastname: Becker
authors.forename: Michael T
authors.initials: MT
authors.lastname: Barbe
authors.forename: Ingo
authors.initials: I
authors.lastname: Meister
authors.forename: Lena
authors.initials: L
authors.lastname: Liebhart
authors.forename: Timo B
authors.initials: TB
authors.lastname: Roettger
authors.forename: Till
authors.initials: T
authors.lastname: Dembek
authors.forename: Lars
authors.initials: L
authors.lastname: Timmermann
authors.forename: Martine
authors.initials: M
authors.lastname: Grice
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D046690:Deep Brain Stimulation / Q000009:adverse effects*; D020329:Essential Tremor / Q000628:therapy*; D005260:Female; D005858:Germany; D005931:Glottis / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010700:Phonetics; D013060:Speech / Q000502:physiology*; D013064:Speech Disorders / Q000209:etiology* / Q000503:physiopathology; D014831:Voice / Q000502:physiology