title: Word-level intelligibility after caudal zona incerta stimulation for Parkinson's disease.
abstract: OBJECTIVE
  To investigate the effect of caudal zona incerta-deep brain stimulation (cZi-DBS) on word-level speech intelligibility in patients with Parkinson's disease, under both an optimal listening condition and a simulated more naturalistic listening condition.
  
  
  METHODS
  Spoken single words were extracted from read samples collected from 10 bilaterally implanted patients with PD pre- and post-cZi-DBS. Intelligibility was assessed through a transcription task performed by 32 naive listeners under two listening conditions: (i) with low-amplitude conversational speech added as background and (ii) with no added background noise. The listeners' responses were scored in terms of agreement with the intended words.
  
  
  RESULTS
  Post-operatively, the total intelligibility score was significantly lower when cZi stimulation was switched on compared with off, for both listening conditions (with and without added background noise). Intelligibility was also significantly lower on stimulation compared with preoperative recordings, but only when assessed in the listening condition without background noise. The listening condition with added background noise resulted in significantly lower intelligibility scores compared with the no added noise condition for all stimulation conditions.
  
  
  CONCLUSIONS
  The results of this study indicate that cZi-DBS in patients with PD can be detrimental to word-level speech intelligibility.
authors.affiliation: Division of Speech and Language Pathology, Department of Clinical Sciences, Umeå University, Umeå, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Johansson
authors.forename: S
authors.initials: S
authors.lastname: Möller
authors.forename: K
authors.initials: K
authors.lastname: Olofsson
authors.forename: J
authors.initials: J
authors.lastname: Linder
authors.forename: E
authors.initials: E
authors.lastname: Nordh
authors.forename: P
authors.initials: P
authors.lastname: Blomstedt
authors.forename: J
authors.initials: J
authors.lastname: van Doorn
authors.forename: F
authors.initials: F
authors.lastname: Karlsson
mesh_terms: D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000628:therapy*; D013064:Speech Disorders / Q000209:etiology / Q000628:therapy; D013065:Speech Intelligibility; D065820:Zona Incerta / Q000502:physiology
keywords: Parkinson's disease; caudal zona incerta; deep brain stimulation; speech intelligibility