title: Predictors of neuropsychological outcome in patients following microelectrode-guided pallidotomy for Parkinson's disease.
abstract: OBJECTIVE
  The authors studied neuropsychological performance following microelectrode-guided posteroventral pallidotomy in patients with Parkinson's disease (PD) and evaluated correlations with presurgical and surgical factors.
  
  
  METHODS
  Neuropsychological changes 3 months (43 patients) and 12 months (27 patients) after microelectrode-guided pallidotomy for PD are reported in a series of 44 consecutive patients with the disease, who improved neurologically, as measured by the Unified Parkinson's Disease Rating Scale (UPDRS) in both the "off' (p<0.001) and best "on" (p<0.001) states. Findings of the vocabulary subtest of the Wechsler Adult Intelligence Scale-Revised (p<0.01), Letter Fluency (p<0.001), Verbal Fluency for semantic categories (p<0.001), and the Wisconsin Card Sorting Test (p<0.01) showed a significant decline in neuropsychological performance in patients 3 months after undergoing left-sided pallidotomy. Impairment in the language domain (semantic fluency) persisted at the 12-month follow-up examination (p<0.01). Visual memory improved after right-sided pallidotomies (p<0.01 after 3 months), with a nonsignificant trend toward persistent improvement 1 year postsurgery (p<0.02 after 12 months). Preoperative semantic fluency was influenced by patient age (p<0.001) and by the width of the third ventricle (p<0.05), as measured by magnetic resonance imaging. A regression model revealed that semantic fluency 3 months postoperatively was significantly affected by the baseline score (p<0.001), side of surgery (p<0.001), handedness (p<0.01), and patient age (p<0.05). However, postoperative lesion volume, lesion location, number of tracks, number of lesions, distance from anatomical landmarks, or UPDRS score did not significantly contribute to neuropsychological outcome.
  
  
  CONCLUSIONS
  Neuropsychological changes in a cohort of patients with PD who underwent pallidotomy and experienced excellent clinical benefits and minimum postoperative complications, emphasize the importance of neuropsychological examinations and further investigation of predictive factors.
authors.affiliation: Department of Neurosurgery, Mayo Clinic Jacksonville, Florida, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Obwegeser
authors.forename: R J
authors.initials: RJ
authors.lastname: Uitti
authors.forename: J A
authors.initials: JA
authors.lastname: Lucas
authors.forename: R J
authors.initials: RJ
authors.lastname: Witte
authors.forename: M F
authors.initials: MF
authors.lastname: Turk
authors.forename: R E
authors.initials: RE
authors.lastname: Wharen
mesh_terms: D000368:Aged; D003071:Cognition; D015331:Cohort Studies; D005260:Female; D005917:Globus Pallidus / Q000601:surgery*; D006801:Humans; D007361:Intelligence Tests; D007802:Language; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000523:psychology / Q000601:surgery*; D011237:Predictive Value of Tests; D016896:Treatment Outcome