PASSIVE EVENT-RELATED POTENTIALS BY A SINGLE TONE IN PERSONALITY DISORDERS

EEG Markers in Emotionally Unstable Personality Disorder-A Possible Outcome Measure for Neurofeedback: A Narrative Review

Objectives. There is growing evidence for the use of biofeedback (BF) in affective disorders, dissocial personality disorder, and in children with histories of abuse. Electroencephalogram (EEG) markers could be used as neurofeedback in emotionally unstable personality disorder (EUPD) management especially for those at high risk of suicide when emotionally aroused. This narrative review investigates the evidence for EEG markers in EUPD. Methods. PRISMA guidelines were used to conduct a narrative review. A structured search method was developed and implemented in collaboration with an information specialist. Studies were identified via 3 electronic database searches of MEDLINE, Embase, and PsycINFO. A predesigned inclusion/exclusion criterion was applied to selected papers. A thematic analysis approach with 5 criteria was used. Results. From an initial long list of 5250 papers, 229 studies were identified and screened, of which 44 met at least 3 of the predesigned inclusion criteria. No research to date investigates EEG-based neurofeedback in EUPD. A number of different EEG biomarkers are identified but there is poor consistency between studies. Conclusions. The findings heterogeneity may be due to the disorder complexity and the variable EEG related parameters studied. An alternative explanation may be that there are a number of different neuromarkers, which could be clustered together with clinical symptomatology, to give new subdomains. Quantitative EEGs in particular may be helpful to identify more specific abnormalities. EEG standardization of neurofeedback protocols based on specific EEG abnormalities detected may facilitate targeted use of neurofeedback as an intervention in EUPD.

N2 amplitude modulation across the antisocial spectrum: a meta-analysis

Despite the accumulated knowledge on antisocial behavior and the positive event-related potential peaking around 300 ms (P3), less is known about the preceding negative electrophysiological response around 200 ms (N2). A systematic search of the literature was conducted to analyze the N2 modulation across the antisocial spectrum. Thirty-seven studies (n = 1199) were retrieved to the quantitative analysis. Reduced N2 amplitudes were found in the more severe antisocial manifestations (violent behavior and antisocial personality disorder), which is consistent with previous findings on P3 alterations and N2 reduced amplitudes in externalizing disorders. Findings on psychopathy were mixed, also in accordance with previous P3 results. From a dimensional lens, this supports the heterogeneity of the psychopathic personality structure: impulsivity features are a closer attribute of antisocial behavior and thus may be associated with N2 reduction, while adaptive psychopathic traits may be associated with intact (or even increased) N2 amplitude. The increased N2 amplitudes observed in impulsive behavior challenge, however, the previous meta-analytic findings. As most of the studies on impulsivity include subclinical samples, it leads to the hypothesis that some compensatory mechanisms can still occur at a subclinical level, reflecting the need for heightened allocation of brain resources to yield similar performances. Importantly, inhibition was the core deficit to explain N2 blunted amplitudes, alongside with deficits in the frontal brain region. From our findings, the reduction in P3 amplitude across the antisocial spectrum may be detected in the previous N2 time window.