title: Declines in switching underlie verbal fluency changes after unilateral pallidal surgery in Parkinson's disease.
abstract: Declines in verbal fluency are consistently reported in patients with Parkinson's disease (PD) after pallidal surgery. In the present study, the clustering and switching components of semantic or category fluency (oral naming of items obtainable in supermarkets) were examined at baseline and four months after unilateral deep brain stimulation or pallidotomy in 45 patients with PD (30 left, 15 right pallidal surgery). Post-operative declines were observed for supermarket fluency total score and switching, but not for average cluster size. These findings support the proposal that semantic fluency decrements after pallidal surgery reflect a disruption of frontal-basal ganglia circuits mediating efficient shifting between semantic categories, or perhaps efficient access to categories, rather than a degradation of semantic stores.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, School of Medicine, University of Washington, Seattle, WA, USA. atroster@u.washington.edu
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Tröster
authors.forename: Steven Paul
authors.initials: SP
authors.lastname: Woods
authors.forename: Julie A
authors.initials: JA
authors.lastname: Fields
authors.forename: Charlotte
authors.initials: C
authors.lastname: Hanisch
authors.forename: William W
authors.initials: WW
authors.lastname: Beatty
mesh_terms: D001479:Basal Ganglia / Q000503:physiopathology; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology; D004599:Electric Stimulation Therapy; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D007839:Functional Laterality / Q000502:physiology*; D005917:Globus Pallidus / Q000502:physiology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000503:physiopathology; D009483:Neuropsychological Tests; D019635:Neurosurgical Procedures / Q000379:methods; D010300:Parkinson Disease / Q000503:physiopathology / Q000601:surgery*; D011183:Postoperative Complications; D011300:Preoperative Care; D011596:Psychomotor Disorders / Q000175:diagnosis / Q000209:etiology; D012660:Semantics; D012720:Severity of Illness Index; D013064:Speech Disorders / Q000175:diagnosis / Q000209:etiology*