title: Cognitive deficits in patients with obsessive-compulsive disorder - electroencephalography correlates.
abstract: BACKGROUND
  Obsessive-compulsive disorder (OCD) is associated with cognitive dysfunction. Although there are several studies focused on the neurobiology of OCD, little is known about the biological correlates of the cognitive deficit linked to this disorder. The aim of our study was to examine the association between cognitive impairment and current source density markers in patients with OCD.
  
  
  METHODS
  Resting-state eyes-closed electroencephalography (EEG) data were recorded in 20 patients with OCD and 15 healthy controls who were involved in the study. Cortical EEG sources were estimated by standardized low-resolution electromagnetic tomography in seven frequency bands: delta (1.5-6 Hz), theta (6.5-8 Hz), alpha-1 (8.5-10 Hz), alpha-2 (10.5-12 Hz), beta-1 (12.5-18 Hz), beta-2 (18.5-21 Hz), and beta-3 (21.5-30 Hz). Cognitive performance was measured by the Trail-Making Test (versions A and B), Stroop CW Test, and D2 Test.
  
  
  RESULTS
  Frontal delta and theta EEG sources showed significantly higher activity in the whole group of patients with OCD (N=20) than in control subjects (N=15). Subsequent analysis revealed that this excess of low-frequency activity was present only in the subgroup of eleven patients with cognitive impairment (based on the performance in the Trail-Making Test - A). The subgroup of patients with normal cognitive functions (N=9) did not differ in cortical EEG sources from healthy controls.
  
  
  CONCLUSIONS
  The present results suggest that frontal low-frequency cortical sources of resting-state EEG rhythms can distinguish groups of cognitively impaired and cognitively intact patients with OCD. Based on our results, future studies should consider whether the present methodological approach provides clinically useful information for the revelation of cognitive impairment in patients with OCD.
authors.affiliation: Department of Psychiatry, University Hospital Olomouc, Olomouc, Czech Republic; Department of Psychiatry, Palacky University Olomouc, Olomouc, Czech Republic.
authors.forename: Dana
authors.initials: D
authors.lastname: Kamaradova
authors.affiliation: Department of Psychiatry, University Hospital Olomouc, Olomouc, Czech Republic; Department of Psychiatry, Palacky University Olomouc, Olomouc, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Hajda
authors.affiliation: Department of Psychiatry, University Hospital Olomouc, Olomouc, Czech Republic; Department of Psychiatry, Palacky University Olomouc, Olomouc, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Prasko
authors.affiliation: Department of Psychiatry, University Hospital Olomouc, Olomouc, Czech Republic; Department of Psychiatry, Palacky University Olomouc, Olomouc, Czech Republic.
authors.forename: Jiri
authors.initials: J
authors.lastname: Taborsky
authors.affiliation: Department of Psychiatry, University Hospital Olomouc, Olomouc, Czech Republic; Department of Psychiatry, Palacky University Olomouc, Olomouc, Czech Republic.
authors.forename: Ales
authors.initials: A
authors.lastname: Grambal
authors.affiliation: Department of Psychiatry, University Hospital Olomouc, Olomouc, Czech Republic; Department of Psychiatry, Palacky University Olomouc, Olomouc, Czech Republic.
authors.forename: Klara
authors.initials: K
authors.lastname: Latalova
authors.affiliation: Department of Psychiatry, University Hospital Olomouc, Olomouc, Czech Republic; Department of Psychiatry, Palacky University Olomouc, Olomouc, Czech Republic.
authors.forename: Marie
authors.initials: M
authors.lastname: Ociskova
authors.affiliation: National Institute of Mental Health, Klecany, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Brunovsky
authors.affiliation: Department of Neurology, University Hospital Olomouc, Olomouc, Czech Republic; Department of Neurology, Palacky University, Olomouc, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Hlustik
keywords: electroencephalography; frontal areas; low-frequency sources; obsessive-compulsive disorder; standardized low-resolution electromagnetic tomography