The Loudness Dependence of Auditory Evoked Potentials in patients with borderline personality disorder and healthy control subjects

Background: Alterations in the central serotonergic system are considered to be involved in the pathophysiology of the borderline personality disorder (BPD). The loudness dependence of the N1/P2 component of auditory evoked potentials (LD) has been shown to indirectly reflect central serotonergic activity. The aim of this study was to investigate LD in patients with BPD and healthy controls, and to investigate the association between LD and scores of impulsiveness, aggression and anxiety. Methods: Nine female patients with BPD were compared with nine healthy female control subjects. Anger, impulsiveness and anxiety were assessed with the State-Trait Anger Expression Inventory, the Barratt Impulsiveness Scale and the State-Trait Anxiety Inventory. We assessed the LD upon a pseudo-randomized presentation of auditory stimuli of five different loudness intensities. The LD of the relevant subcomponents reflecting the serotonergic activity of the primary auditory cortex (tangential dipol) was investigated using dipole source analysis. Results: The mean LD of the tangential dipole was significantly higher in BPD patients than in healthy controls. Positive correlations between LD and subscores of anger and anxiety were found. Conclusion: Our data are in line with earlier findings of a pronounced loudness dependence of auditory evoked potentials in patients with BPD and support the hypothesis of a serotonergic dysregulation in the pathophysiology of BPD.