Several studies using electroencephalography (EEG) demonstrate that the processing of feedback in patients suffering from borderline personality disorder (BPD) is altered in comparison to healthy controls. Differences occur in the theta (ca. 5 Hz) and high-beta frequency-ranges (ca. 20 Hz) of oscillations in response to negative and positive feedback, respectively. However, alpha (ca. 10 Hz) and low-beta (ca. 15 Hz) oscillations have also been shown to be involved in feedback processing. We hypothesized that additional alterations might occur in these frequency ranges in BPD. Eighteen patients with BPD and twenty-two healthy controls performed a gambling task while 64-channel-EEG was recorded. Induced oscillatory responses to positive (i.e. gain) and negative (i.e. loss) feedback in the alpha and low-beta frequency range were investigated. No significant differences were found in the alpha frequency range. Regarding the low-beta frequency range a significant Group (i.e. BPD vs. healthy controls) × Valence (i.e. gain vs. loss) interaction in the time frame between 600 and 700 milliseconds after feedback was found. This effect showed a significant correlation with symptom severity (assessed with the BSL-23). The results indicate that feedback processing in BPD could be more heavily altered than previously expected, with more severe symptomatology being linked to stronger alterations in oscillatory responses to feedback in the low-beta range.
