Verarbeitung emotionaler Reize bei Personen mit einer Zwangsstörung
Hemispheric asymmetry of alpha band power in the electroencephalogram (EEG) has been linked to approach/avoidance motivation and may index the risk for anxiety disorders and depression. Alpha asymmetry has not yet been thoroughly investigated in obsessive-compulsive disorder (OCD). We quantified lower alpha band power (810 Hz) as well as upper alpha band, theta, and beta band power at frontal and parietal electrodes in 18 OCD patients and 18 matched healthy controls during blocks of rest and presentation of neutral, aversive, and OCD-related pictures. Patients showed a relative shift of frontal alpha activity in the 8-10 Hz band to the left hemisphere across all conditions. This shift was not observed over parietal areas, and also did not show in the upper alpha, and the theta and beta bands. Aversive pictures induced a left-shift in both groups relative to all other conditions. Altered hemispheric distribution of lower alpha band activity supports the hypothesis of relatively increased avoidance motivation in OCD. Unlike in other anxiety disorders, altered asymmetry was not confined to conditions evoking negative emotions. Instead, it appears to be more trait-like in OCD, suggesting a link to depression. Ischebeck, Endrass, Simon & Kathmann 3