QEEG correlates of cognitive impairment in obsessive compulsive patients

摘要: Similar to patients with schizophrenia or bipolar affective disorder many studies demonstrated presence of cognitive impairment in OCD (obsessive-compulsive disorder) patients. Aim of our study was to identify correlates of cognitive impairment in OCD patients using quantitative EEG.Resting-state eyes-closed EEG data were recorded in twenty OCD patients and fifteen healthy controls that were involved in the study. Cortical EEG sources were estimated by standardized low-resolution electromagnetic tomography (sLORETA)in seven frequency bands: delta (1.5–6Hz), theta (6.5–8Hz), alpha-1 (8.5–10Hz), alpha-2 (10.5–12Hz), beta-1 (12.5–18Hz), beta-2 (18.5–21Hz) and beta-3 (21.5–30Hz). Cognitive performance was measured by the Trail-Making Test (version A and B).Frontal delta and theta EEG sources showed significantly higher activity in the whole group of OCD patients (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 11 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.The present results suggest that frontal low-frequency cortical sources of resting state EEG rhythms can distinguish groups of cognitively impaired and cognitively intact OCD patients. Based on our results, future studies should consider whether the present methodological approach provides clinically useful information for the revelation of cognitive impairment in OCD patients.