title: Meta-analytical and electrophysiological evidence for executive dysfunction in primary dystonia.
abstract: Impaired motor control in primary dystonia has been linked to cortico-basal ganglia alterations that may also give rise to changes in executive functioning. However, no conclusive evidence for executive dysfunction in patients with primary dystonia has been reported yet. We conducted a meta-analysis of the relationship between primary dystonia and performance on the Wisconsin Card Sorting Test (WCST), an established test of executive functioning. Its results revealed a significant effect of medium size, indicating that primary dystonia is associated with moderate performance deficits on the WCST. Building on this finding, we conducted an event-related potential (ERP) study to elucidate the cognitive and neural mechanisms underlying executive dysfunction in primary dystonia. Eighteen patients with blepharospasm, a common form of primary focal dystonia, and 34 healthy matched controls completed a computerized version of the WCST. We specifically compared indicators of two distinct components of executive functioning: set shifting and rule inference. On a behavioral level, blepharospasm patients seemed to have particular difficulty integrating information to infer the correct task rule. In addition, P3a amplitude (as an electrophysiological marker of rule-inference processes) was selectively attenuated in blepharospasm patients. Executive dysfunction in blepharospasm can thus rather be attributed to a rule-inference deficit, whereas set-shifting abilities appear to be relatively unaffected by the disease. Moreover, P3a amplitude attenuation was related to disease duration, indicating that this ERP might serve as a neural indicator of disease progression and executive dysfunction in primary dystonia. These results demonstrate for the first time that pathophysiological alterations in primary dystonia might affect cortical activation for executive functioning.
authors.affiliation: Department of Neurology, Hannover Medical School, Hannover, Germany. Electronic address: lange.florian@mh-hannover.de.
authors.forename: Florian
authors.initials: F
authors.lastname: Lange
authors.affiliation: Department of Neurology, Hannover Medical School, Hannover, Germany.
authors.forename: Caroline
authors.initials: C
authors.lastname: Seer
authors.affiliation: Department of Neurology, Hannover Medical School, Hannover, Germany.
authors.forename: Carolin
authors.initials: C
authors.lastname: Salchow
authors.affiliation: Department of Neurology, Hannover Medical School, Hannover, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Dengler
authors.affiliation: Department of Neurology, Hannover Medical School, Hannover, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Dressler
authors.affiliation: Department of Neurology, Hannover Medical School, Hannover, Germany.
authors.forename: Bruno
authors.initials: B
authors.lastname: Kopp
mesh_terms: D000368:Aged; D001764:Blepharospasm / Q000503:physiopathology / Q000523:psychology*; D001921:Brain / Q000503:physiopathology*; D020821:Dystonic Disorders / Q000503:physiopathology / Q000523:psychology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012718:Set, Psychology
keywords: Blepharospasm; Event-related potentials; Executive dysfunction; Primary dystonia; Wisconsin Card Sorting Test