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

Chronic social stress during early development is involved in antisocial maltreatment behavior in mice

Purpose

Early-life stress can cause brain inflammation and affect social behavior in adulthood. In humans, maltreated (abused or neglected) children often exhibit antisocial behavior, including violent and sadistic behavior, in adulthood. However, it is unknown whether maltreatment behavior occurs in rodents. Here, we developed an assay system to evaluate conspecific maltreatment behavior in the mouse.

Methods

To assess maltreatment behavior, we devised a two-chamber apparatus separated by a transparent partition, in which one chamber was provided with a nose-poking hole that would trigger foot shocks onto the other. Lidocaine was used to inhibit neural activity in vivo. Brain oscillations were investigated by electroencephalograph. Enzyme-linked immunosorbent assay was used for protein assay. The mouse model was sequentially subjected to maternal separation (MS), social defeat (SD), and social isolation (SI) in that order (MS/SD/SI model).

Results

Inactivation of the anterior cingulate cortex and medial prefrontal cortex increased the level of nose-poking. Maltreatment behavior provoked changes in oxytocin, corticosterone, and brain-derived neurotrophic factor levels. MS/SD/SI mice exhibited more sustained nose-poking behavior during the experiment, resulting in increased foot shocks to the mouse in the opposite chamber. Abnormal brain oscillations were observed in the MS/SD/SI mice.

Conclusion

The MS/SD/SI model and maltreatment-behavior assay may be useful not only to study the relationship between social stress in childhood and antisocial behavior in adulthood, but also for study of etiology, pathology, or treatment for brain disorders, such as psychopathy.

Hyperreactivity and Impaired Habituation of Startle Amplitude During Unpleasant Pictures in Borderline but Not Schizotypal Personality Disorder: Quantifying Emotion Dysregulation

BACKGROUND

Borderline personality disorder (BPD) is characterized by greater intensity of reactions to unpleasant emotional cues and a slower-than-normal return of these responses to baseline. Habituation is defined as decreased response to repeated stimulation. Affect-modulated startle (AMS), a translational psychophysiological approach, is mediated by the amygdala and used to study emotion processing in both humans and animals. This is the first study to examine the specificity of habituation anomalies in BPD during passive emotional and neutral picture processing.

METHODS

A total of 90 participants were studied: patients with BPD (n = 35), patients with schizotypal personality disorder (n = 26; included as a psychopathological comparison group), and healthy control subjects (n = 29). Participants received rigorous clinical assessments, and patients were unmedicated. AMS was examined during a series of intermixed unpleasant, neutral, and pleasant pictures.

RESULTS

Compared with the other groups, patients with BPD showed greater overall AMS during unpleasant pictures and prolonged habituation of startle amplitude during unpleasant pictures from early to later trials. The groups did not differ in AMS during neutral or pleasant pictures or self-reported picture valence. Among the patients with BPD, prolonged habituation to unpleasant pictures was associated with greater symptom severity and suicidal/self-harming behavior.

CONCLUSIONS

These findings 1) indicate that abnormal processing of and habituation to unpleasant pictures is observed in BPD but not schizotypal personality disorder, suggesting that these deficits are not simply characteristics of personality disorders in general; 2) are consistent with studies showing deficient amygdala habituation to unpleasant pictures in BPD; and 3) have significant implications for clinical assessment and treatment of BPD, e.g., alternative therapies for BPD such as gradual exposure to unpleasant emotional stimuli or amygdala neurofeedback may aid habituation deficits.

Auditory event-related electroencephalographic potentials in borderline personality disorder

BACKGROUND

Borderline Personality Disorder (BPD) is characterized by mood dysregulation, impulsivity, identity disturbances, and a higher risk for suicide. Currently, the diagnosis is solely based on clinical observation of overt symptoms, and this can delay the detection of the disease and the timely start of appropriate treatment. Several candidate clinical tools have been studied to better characterize BPD, including event-related potentials (ERP). This review aimed at summarizing the results of the available ERP studies on BPD to clarify the possible application of this technique in the early diagnosis of BPD.

METHODS

A bibliographic search on PubMed and PsycInfo was performed in order to identify studies comprising individuals with BPD diagnosis and a control group that evaluated the ERP elicited by auditory stimuli.

RESULTS

Ten studies that explored various ERP components associated with auditory stimuli in BPD were included. Overall, the results showed that positive ERP (P50, P100, and P300) amplitude and latencies as well as loudness dependance were altered in BPD patients compared to controls, possibly reflecting deficits involving attention, mainly at its early stage, and executive functions.

LIMITATIONS

The reviewed studies used different ERP approaches and non-homogeneous BPD diagnostic criteria.

CONCLUSIONS

Auditory ERP appear to be a promising tool for the assessment of BPD patients, especially for early diagnosis and evaluation of cognitive symptoms.

The Influence of Filters on EEG-ERP Testing: Analysis of Motor Cortex in Healthy Subjects

The raw EEG signal is always contaminated with many different artifacts, such as muscle movements (electromyographic artifacts), eye blinking (electrooculographic artifacts) or power line disturbances. All artifacts must be removed for correct data interpretation. However, various noise reduction methods significantly influence the final shape of the EEG signal and thus its characteristic values, latency and amplitude. There are several types of filters to eliminate noise early in the processing of EEG data. However, there is no gold standard for their use. This article aims to verify and compare the influence of four various filters (FIR, IIR, FFT, NOTCH) on the latency and amplitude of the EEG signal. By presenting a comparison of selected filters, the authors intend to raise awareness among researchers as regards the effects of known filters on latency and amplitude in a selected area-the sensorimotor area.

Borderline and Depression: A Thin EEG Line

In everyday clinical practice, there is an ongoing debate about the nature of major depressive disorder (MDD) in patients with borderline personality disorder (BPD). The underlying research does not give us a clear distinction between those 2 entities, although depression is among the most frequent comorbid diagnosis in borderline personality patients. The notion that depression can be a distinct disorder but also a symptom in other psychopathologies led our team to try and delineate those 2 entities using 146 EEG recordings and machine learning. The utilized algorithms, developed solely for this purpose, could not differentiate those 2 entities, meaning that patients suffering from MDD did not have significantly different EEG in terms of patients diagnosed with MDD and BPD respecting the given data and methods used. By increasing the data set and the spatiotemporal specificity, one could have a more sensitive diagnostic approach when using EEG recordings. To our knowledge, this is the first study that used EEG recordings and advanced machine learning techniques and further confirmed the close interrelationship between those 2 entities.

Review of Neuropsychological and Electrophysiological Correlates of Callous-unemotional Traits in Children: Implications for EEG Neurofeedback Intervention

Conduct disorder is a significant psychiatric disorder of childhood and adolescence. The Diagnostic and Statistical Manual of Mental Disorders, fifth version (DSM-5), added the limited prosocial specifier to identify those individuals who exhibit a more severe pattern of behavior characterized by a callous and unemotional (CU) interpersonal style across multiple settings and relationships. This review has attempted to summarize the relevant research focusing on the significance of CU interpersonal style in the development of psychopathy. The primary focus was on the electrophysiological and neuropsychological correlates of CU traits and their implication on the treatment protocol using neurofeedback training for children with such traits. The source of the literature search was PubMed, which majorly uses the MEDLINE database. The keywords used included CU traits, conduct disorder, child psychopathy, empathy, electrophysiology, criminal behavior, neuropsychology, neurofeedback training, and so on. Studies from the last 15 years were considered for the review. This review revealed that children with conduct disorder and high-CU traits with a combination of reactive and proactive aggression are more likely to develop psychopathy. Evidence suggests that these children have distinct forms of electrophysiological and neuropsychological correlates. However, research in this area is still not conclusive as they yield variation in findings. Studies on the efficacy of neurofeedback training on reducing symptoms such as impulsivity, hostility, and psychopathy indicate that neurofeedback training can be a promising treatment alternative for children with severe conduct disorder.