title: Executive control in chronic schizophrenia: A perspective from manual stimulus-response compatibility task performance.
abstract: BACKGROUND
  Antisaccade deficits are a well-documented pathophysiological characteristic in schizophrenia. However, it is yet unclear whether these findings reflect a specific oculomotor deficit, general psychomotor impairment or disturbance in executive control mechanisms.
  
  
  METHODS
  Performance in a manual stimulus-response compatibility (SRC) task and a neuropsychological test-battery covering different cognitive and motor domains were obtained in 28 patients with chronic schizophrenia. It was compared with a normative cohort of healthy subjects and validated by comparison with a sub-sample of that cohort consisting of 28 age, gender and education matched controls.
  
  
  RESULTS
  Patients showed significantly worse performance than controls in tests requiring maintenance or manipulating of multiple components but were unimpaired in simple motor, memory or executive tasks. In the SRC task patients had a significantly worse performance in the congruent condition and also a significantly higher increase in error rate from the congruent to the incongruent condition. There were, however, neither a group difference nor a group-by-condition interaction with respect to reaction times.
  
  
  CONCLUSIONS
  : Our results provide evidence against an isolated oculomotor deficit but also against an undifferentiated psychomotor dysfunction in chronic schizophrenia. Rather, in synopsis with previous reports on antisaccade performance, it becomes evident that the degree of impairment follows closely the amount of executive control required in a task, which in turn may relate to dysfunctional top-down bias of the prefrontal cortex arising from unstable task instructions.
authors.affiliation: Department of Psychiatry & Psychotherapy, RWTH Aachen University, Aachen, Germany. SEickhoff@ukaachen.de
authors.forename: Simone D
authors.initials: SD
authors.lastname: Behrwind
authors.forename: Manuel
authors.initials: M
authors.lastname: Dafotakis
authors.forename: Sarah
authors.initials: S
authors.lastname: Halfter
authors.forename: Kerstin
authors.initials: K
authors.lastname: Hobusch
authors.forename: Mark
authors.initials: M
authors.lastname: Berthold-Losleben
authors.forename: Edna C
authors.initials: EC
authors.lastname: Cieslik
authors.forename: Simon B
authors.initials: SB
authors.lastname: Eickhoff
mesh_terms: D002908:Chronic Disease; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance; D011930:Reaction Time; D012565:Schizophrenic Psychology; D014145:Trail Making Test / Q000706:statistics & numerical data; D014888:Wechsler Scales / Q000706:statistics & numerical data