title: Effects of deep brain stimulation in the caudal zona incerta on verbal fluency.
abstract: BACKGROUND
  Deep brain stimulation (DBS) of the caudal zona incerta (cZi) is a relatively unexplored and promising treatment in patients with severe essential tremor (ET). Preliminary data further indicate that the ability to produce language may be slightly affected by the treatment.
  
  
  OBJECTIVE
  To evaluate the effects on verbal fluency following cZi DBS in patients with ET.
  
  
  METHODS
  Seventeen consecutive patients who had undergone DBS of the cZi for ET were tested regarding verbal fluency before surgery, 3 days after surgery and after 1 year. Ten patients were also evaluated by comparing performance on versus off stimulation after 1 year.
  
  
  RESULTS
  The total verbal fluency score decreased slightly, but significantly, from 22.7 (SD = 10.9) before surgery to 18.1 (SD = 7.5) 3 days after surgery (p = 0.036). After 1 year the score was nonsignificantly decreased to 20.1 (SD = 9.7, p = 0.2678). There was no detectable difference between stimulation on and off after 1 year.
  
  
  CONCLUSIONS
  There was a tendency of an immediate and mostly transient postoperative decline in verbal fluency following cZi DBS for ET. In some of the patients this reduction was, however, more pronounced and also sustained over time.
authors.affiliation: Department of Clinical Neuroscience, Neurosurgery, Karolinska University Hospital, Stockholm, Sweden. anders.fytagoridis@neuro.umu.se
authors.forename: Anders
authors.initials: A
authors.lastname: Fytagoridis
authors.forename: Rickard L
authors.initials: RL
authors.lastname: Sjöberg
authors.forename: Mattias
authors.initials: M
authors.lastname: Åström
authors.forename: Anna
authors.initials: A
authors.lastname: Fredricks
authors.forename: Lars
authors.initials: L
authors.lastname: Nyberg
authors.forename: Patric
authors.initials: P
authors.lastname: Blomstedt
mesh_terms: D000368:Aged; D046690:Deep Brain Stimulation / Q000009:adverse effects*; D004292:Dominance, Cerebral; D004567:Electrodes, Implanted / Q000009:adverse effects; D020329:Essential Tremor / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D013064:Speech Disorders / Q000209:etiology* / Q000503:physiopathology; D020531:Subthalamic Nucleus / Q000293:injuries / Q000503:physiopathology*