Set-shifting and behavioral dysfunction in primary focal dystonia

The occurrence of cognitive and behavioral symptoms in patients with primary dystonia remains a matter of debate. We compared 45 patients with primary dystonia with 27 control subjects for performance on neuropsychological tasks with a load on executive-Wisconsin Card Sorting Test (WCST) and Stroop test, and visuospatial-Benton's visual retention test (BVRT) and Block assembly test from Wechsler Adult Intelligence Scale BAT-functions, as well as for intensity of obsessive-compulsive symptoms (Yale Brown Obsessive Compulsive Scale, Y-BOCS). Correlation analysis was performed between neuropsychological performance, dystonia characteristics (duration, age of onset) and severity (Unified Dystonia Rating Scale, UDRS), and Y-BOCS. Patients made more perseverative errors on the WCST (P = 0.042) and had a higher mean Y-BOCS (P = 0.003) score than controls. Timed tests (BVRT, BAT, Stroop test) correlated with UDRS. Y-BOCS, WCST, and UDRS scores were not significantly correlated with one another. These results suggest that patients with primary dystonia may have set-shifting deficits and a higher intensity of obsessive compulsive symptoms when compared to healthy subjects. This may reflect a pattern of complex neurophysiological dysfunction involving dorsolateral, orbitofrontal, and motor frontostriatal circuits. (C) 2007 Movement Disorder Society.