Neuropsychological assessment of aggressive offenders: a Delphi consensus study

Objective

This study explores the intricate relationship between cognitive functioning and aggression, with a specific focus on individuals prone to reactive or proactive aggression. The purpose of the study was to identify important neuropsychological constructs and suitable tests for comprehending and addressing aggression.

Methods

An international panel of 32 forensic neuropsychology experts participated in this three-round Delphi study consisting of iterative online questionnaires. The experts rated the importance of constructs based on the Research Domain Criteria (RDoC) framework. Subsequently, they suggested tests that can be used to assess these constructs and rated their suitability.

Results

The panel identified the RDoC domains Negative Valence Systems, Social Processes, Cognitive Systems and Positive Valence Systems as most important in understanding aggression. Notably, the results underscore the significance of Positive Valence Systems in proactive aggression and Negative Valence Systems in reactive aggression. The panel suggested a diverse array of 223 different tests, although they noted that not every RDoC construct can be effectively measured through a neuropsychological test. The added value of a multimodal assessment strategy is discussed.

Conclusions

This research advances our understanding of the RDoC constructs related to aggression and provides valuable insights for assessment strategies. Rather than suggesting a fixed set of tests, our study takes a flexible approach by presenting a top-3 list for each construct. This approach allows for tailored assessment to meet specific clinical or research needs. An important limitation is the predominantly Dutch composition of the expert panel, despite extensive efforts to diversify.

The Predictive Value of Early-Life Trauma, Psychopathy, and the Testosterone-Cortisol Ratio for Impulsive Aggression Problems in Veterans

Background

In this study, we examined whether early-life trauma, psychopathy, and the testosterone/cortisol ratio predicted impulsive aggression problems in veterans.

Method

A sample of 49 male veterans with impulsive aggression problems and 51 nonaggressive veterans were included in the study. Logistic regression analysis was performed with early-life trauma, primary and secondary psychopathy, and testosterone/cortisol ratio as continuous predictor variables; impulsive aggression status was entered as a binary outcome measure. Correlation analyses were conducted to examine pairwise relations among the predictors.

Results

Results indicated that early-life trauma and secondary psychopathy, but not the testosterone/cortisol ratio or primary psychopathy, were significant predictors of impulsive aggression status.

Conclusions

The current results indicate that early-life trauma and secondary psychopathy are risk factors for impulsive aggression problems among veterans. Future studies are needed to determine the exact causal relations among the variables examined here.

Fearful Faces do Not Lead to Faster Attentional Deployment in Individuals with Elevated Psychopathic Traits

In the current study, a gaze-cueing experiment (similar to Dawel et al. 2015) was conducted in which the predictivity of a gaze-cue was manipulated (non-predictive vs highly predictive). This was done to assess the degree to which individuals with elevated psychopathic traits can use contextual information (i.e., the predictivity of the cue). Psychopathic traits were measured with the Self-Report Psychopathy Scale-Short Form (SRP-SF) in a mixed sample (undergraduate students and community members). Results showed no group difference in reaction times between high and non-predictive cueing blocks, suggesting that individuals with elevated psychopathic traits can indeed use contextual information when it is relevant. In addition, we observed that fearful facial expressions did not lead to a change in reaction times in individuals with elevated psychopathic traits, whereas individuals with low psychopathic traits showed speeded responses when confronted with a fearful face, compared to a neutral face. This suggests that fearful faces do not lead to faster attentional deployment in individuals with elevated psychopathic traits.

Visual attention in violent offenders: Susceptibility to distraction

Impairments in executive functioning give rise to reduced control of behavior and impulses, and are therefore a risk factor for violence and criminal behavior. However, the contribution of specific underlying processes remains unclear. A crucial element of executive functioning, and essential for cognitive control and goal-directed behavior, is visual attention. To further elucidate the importance of attentional functioning in the general offender population, we employed an attentional capture task to measure visual attention. We expected offenders to have impaired visual attention, as revealed by increased attentional capture, compared to healthy controls. When comparing the performance of 62 offenders to 69 healthy community controls, we found our hypothesis to be partly confirmed. Offenders were more accurate overall, more accurate in the absence of distracting information, suggesting superior attention. In the presence of distracting information offenders were significantly less accurate compared to when no distracting information was present. Together, these findings indicate that violent offenders may have superior attention, yet worse control over attention. As such, violent offenders may have trouble adjusting to unexpected, irrelevant stimuli, which may relate to failures in self-regulation and inhibitory control.

Top-down attention and selection history in psychopathy: Evidence from a community sample

Psychopathy is a severe personality disorder, the core of which pertains to callousness, an entitled and grandiose interpersonal style often accompanied by impulsive and reckless endangerment of oneself and others. The response modulation theory of psychopathy states that psychopathic individuals have difficulty modulating top-down attention to incorporate bottom-up stimuli that may signal important information but are irrelevant to current goals. However, it remains unclear which particular aspects of attention are impaired in psychopathy. Here, we used 2 visual search tasks that selectively tap into bottom-up and top-down attention. In addition, we also looked at intertrial priming, which reflects a separate class of processes that influence attention (i.e., selection history). The research group consisted of 65 participants that were recruited from the community. Psychopathic traits were measured with the Psychopathic Personality Inventory (PPI; Uzieblo, Verschuere, & Crombez, 2007). We found that bottom-up attention was unrelated to psychopathic traits, whereas elevated psychopathic traits were related to deficits in the use of cues to facilitate top-down attention. Further, participants with elevated psychopathic traits were more strongly influenced by their previous response to the target. These results show that attentional deficits in psychopathy are largely confined to top-down attention and selection history.

A latent variable analysis of the Psychopathy Checklist-Revised and behavioral inhibition system/behavioral activation system factors in North American and Swedish offenders

An influential neurobiological model of personality is the Reinforcement Sensitivity Theory, which postulates how basic motivational systems (behavioral activation system [BAS], behavioral inhibition system [BIS]) can help account for the development and expression of individual differences in personality. Earlier research has documented a link between psychopathic personality and the BIS/BAS scale (Carver & White, 1994), which was developed to measure the behavioral inhibition and activation systems. However, no studies have examined how latent BIS/BAS factors and the 4 empirically derived Psychopathy Checklist-Revised (PCL-R) psychopathy factors (Hare & Neumann, 2008) are associated across different cultures. In the current study, structural equation modeling was used to determine how the 4 PCL-R factors were able to predict BIS/BAS factors using 2 large independent samples of male offenders (North American N = 908; Swedish N = 242). The results were in line with theory and revealed a negative relationship between the PCL-R Affective factor and the BIS factor as well as positive relationships between the PCL-R Antisocial and Lifestyle factors with the BAS factor. Overall, the results of the current study provide evidence of cross-cultural generalizability for the associations between the PCL-R factors and the BIS-BAS factors. Taken together, the PCL-R psychopathy factors were able to account for meaningful variance in the BIS-BAS factors and further support a dimensional approach to understanding the psychopathy construct across cultures.

Abnormal interhemispheric connectivity in male psychopathic offenders

BACKGROUND

Psychopathic offenders inevitably violate interpersonal norms and frequently resort to aggressive and criminal behaviour. The affective and cognitive deficits underlying these behaviours have been linked to abnormalities in functional interhemispheric connectivity. However, direct neurophysiological evidence for dysfunctional connectivity in psychopathic offenders is lacking.

METHODS

We used transcranial magnetic stimulation combined with electroencephalography to examine interhemispheric connectivity in the dorsolateral and motor cortex in a sample of psychopathic offenders and healthy controls. We also measured intracortical inhibition and facilitation over the left and right motor cortex to investigate the effects of local cortical processes on interhemispheric connectivity.

RESULTS

We enrolled 17 psychopathic offenders and 14 controls in our study. Global abnormalities in right to left functional connectivity were observed in psychopathic offenders compared with controls. Furthermore, in contrast to controls, psychopathic offenders showed increased intracortical inhibition in the right, but not the left, hemisphere.

LIMITATIONS

The relatively small sample size limited the sensitivity to show that the abnormalities in interhemispheric connectivity were specifically related to the dorsolateral prefrontal cortex in psychopathic offenders.

CONCLUSION

To our knowledge, this study provides the first neurophysiological evidence for abnormal interhemispheric connectivity in psychopathic offenders and may further our understanding of the disruptive antisocial behaviour of these offenders.

The EEG correlates of the TMS-induced EMG silent period in humans

Application of magnetic or electrical stimulation to the motor cortex can result in a period of electromyography (EMG) silence in a tonically active peripheral muscle. This period of EMG silence is referred to as the silent period (SP). The duration of SP shows intersubject variability and reflects the integrity of cortical and corticospinal pathways. A non-invasive technique for assessing the duration of SP is the combination of Transcranial Magnetic Stimulation (TMS) with EMG. Utilizing TMS-EMG, several studies have reported on the shortening or lengthening of SP in neuropsychiatric disorders such as schizophrenia, bipolar disorder, depression, obsessive compulsive disorder, epilepsy, Parkinson's disease, and stroke. However, cortical, corticospinal and peripheral components are difficult to disentangle from EMG alone. Here, we use the multimodal neuroimaging technique of TMS-EMG combined with concurrent electroencephalography (EEG) recording to further examine the cortical origin of SP and the cortical oscillatory activity that underlies SP genesis. We demonstrate that the duration of SP is related to the temporal characteristics of the cortical reactivity and the power of delta to alpha oscillations in both local and remote areas ipsilateral and contralateral to the stimulation site, and beta oscillations locally. We illustrate that, compared to EMG, the EEG indices of the SP provide additional information about the brain dynamics and propose that the EEG measures of SP may be used in future clinical and research investigations to more precisely delineate the mechanisms underlying inhibitory impairments.

Personality goes a long a way: an interhemispheric connectivity study

Throughout the development of psychology the delineation of personality has played a central role. Together with the NEO-PI-R, a questionnaire derived from the Five Factor Model of Personality, and recent advances in research technology it is now possible to investigate the relationship between personality features and neurophysiological brain processes. The NEO-FFI, the short version of the NEO-PI-R, reliably measures five main personality traits: Neuroticism, Extraversion, Openness to experience, Agreeableness, and Conscientiousness. As behavior and some psychiatric disorders have been related to interhemispheric connectivity, the present study used the combination of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to measure frontal interhemispheric connectivity and its association with personality as indexed by the NEO-FFI. Results demonstrated that prefrontal interhemispheric connectivity between the left and right dorsolateral prefrontal cortex correlates with Agreeableness in healthy subjects. This is the first study to relate personality features to interhemispheric connectivity through TMS-EEG and suggests that Agreeableness relates to the effectiveness of prefrontal communication between hemispheres.

High-frequency repetitive transcranial magnetic stimulation to the cerebellum and implicit processing of happy facial expressions

BACKGROUND

Previous research has demonstrated that the cerebellum is involved in emotive and cognitive processes. Furthermore, recent findings suggest high-frequency repetitive transcranial magnetic stimulation (rTMS) to the cerebellum has mood-improving properties. We sought to further explore the effects of cerebellar high-frequency rTMS on implicit processing of emotional stimuli and mood.

METHODS

In a double-blind, crossover study, 15 healthy volunteers received 15 minutes of 20 Hz (5 s on, 5 s off) rTMS over the medial cerebellum, occipital cortex or sham in a randomized counterbalanced order on 3 consecutive days. A masked emotional faces response task measured implicit emotional processing of happy, fearful and neutral facial expressions. We used positive and negative affect scales to evaluate rTMS-related changes in mood.

RESULTS

High-frequency rTMS over the cerebellum was associated with significant increases in masked emotional responses to happy facial expressions only. We observed no changes in consciously experienced mood.

LIMITATIONS

Although the sham rTMS served as our baseline measurement, additional pre-rTMS data showing that reaction time increases immediately after cerebellar rTMS would have made our results more compelling.

CONCLUSION

The results replicate and extend previous findings by establishing a direct relation between the cerebellum and emotive information-processing. The parallel between the present effects of high-frequency cerebellar rTMS and short-term antidepressant therapy regarding the change in implicit processing of positive stimuli in the absence of mood changes is notable and warrants further research.

The role of the cerebellum in the pathophysiology and treatment of neuropsychiatric disorders: a review

The cerebellum has traditionally been looked upon as a brain area primarily involved in motor behaviour. The last decade has however heralded the cerebellum as a brain region of renewed interest for neuropsychiatric disorders. This renewed interest is fuelled by new insights obtained from neuroanatomical research, modern functional neuroimaging and transcranial magnetic stimulation studies. In this review, evidence in support of cerebellar involvement in neuropsychiatric disorders will be presented. In addition, transcranial magnetic stimulation will be introduced as a novel way to study cerebellar contributions to the pathophysiology of psychiatric disorders. In conclusion, a new functional concept of the cerebellum as more than simply a brain area regulating motor control appears mandatory and the involvement of the cerebellum should be considered when studying the neurological basis of neuropsychiatric disorders.