Definition of Impulsivity and Related Terms Following Traumatic Brain Injury: A Review of the Different Concepts and Measures Used to Assess Impulsivity, Disinhibition and other Related Concepts

Lateral fluid percussion injury: A rat model of experimental traumatic brain injury

Traumatic brain injury (TBI) represents one of the leading causes of disability and death worldwide. The annual economic impact of TBI-including direct and indirect costs-is high, particularly impacting low- and middle-income countries. Despite extensive research, a comprehensive understanding of the primary and secondary TBI pathophysiology, followed by the development of promising therapeutic approaches, remains limited. These fundamental caveats in knowledge have motivated the development of various experimental models to explore the molecular mechanisms underpinning the pathogenesis of TBI. In this context, the Lateral Fluid Percussion Injury (LFPI) model produces a brain injury that mimics most of the neurological and systemic aspects observed in human TBI. Moreover, its high reproducibility makes the LFPI model one of the most widely used rodent-based TBI models. In this chapter, we provide a detailed surgical protocol of the LFPI model used to induce TBI in adult Wistar rats. We further highlight the neuroscore test as a valuable tool for the evaluation of TBI-induced sensorimotor consequences and their severity in rats. Lastly, we briefly summarize the current knowledge on the pathological aspects and functional outcomes observed in the LFPI-induced TBI model in rodents.

Disinhibited and angry: Investigating the relationship between social disinhibition and the components of aggression following severe TBI

Social disinhibition and aggression share many similarities. But unlike with aggression, research evidence about social disinhibition following severe traumatic brain injury (TBI) is limited and treatments are missing. Establishing the association between aggression and social disinhibition would facilitate a better conceptualization of these disorders. This study aimed to determine the relationship between social disinhibition and aggression following severe TBI.In this case-control study, 25 individuals with severe TBI and 25 control participants completed the Buss-Perry Aggression Questionnaire (BPAQ), Frontal Systems Behaviour Scale (FrSBe), and Social Disinhibition Interview (SDI).Hierarchical multiple regression analyses revealed that, when controlling for covariates, the inclusion of BPAQ Anger in the model led to a 13% increase in proportion of explained variance of social disinhibition (Adjusted R2 increased from .243 to .363, p < .005). BPAQ Anger was not a significant predictor of SDI scores. Similarly, BPAQ Physical aggression scores did not contribute to the prediction of FrSBe Disinhibition or SDI scores.In conclusion, higher levels of self-reported anger (but no other components of aggression) are associated with higher levels of self-reported social disinhibition. While these findings have potential implications for the treatment of social disinhibition, further research into the possible relationship with aggression should be conducted.

Social disinhibition in acquired brain injury and neurological disease: a concept analysis

BACKGROUND

Social disinhibition is becoming increasingly recognised in the neuropsychological literature as a complex and debilitating sequalae associated with acquired frontal lobe damage. Despite this, the term has been inconsistently defined and described in both clinical and research contexts. The purpose of this paper was to explore and examine the concept of social disinhibition in the context of brain injury and other organic neurological conditions.

METHOD

A literature search for articles published in the English language from journal inception to June 2021 was conducted using MEDLINE, PsycInfo, Embase, CINAHL and Web of Science. A 'concept analysis' was conducted on the identified literature using Walker & Avant's (2019) framework.

RESULTS

The analysis suggested that while several terms are often used interchangeably with social disinhibition, including impulsivity and behavioural dysregulation, these terms may be differentiated and defined separately within the broader domain of 'behaviours of concern'. Attributes, antecedents and consequences of social disinhibition were also identified and discussed.

CONCLUSIONS

Clarifying the concept of social disinhibition has important implications in both clinical and research contexts, including increased understanding of the behaviours, more accurate estimates of incidence and prevalence, and the development and implementation of targeted rehabilitation programmes.

Neuropsychiatric correlates of olfactory identification and traumatic brain injury in a sample of impulsive violent offenders

Background

Olfactory deficits have a diverse etiology and can be detected with simple olfactory tests. Key olfactory pathways are located within the frontal and temporal lobes where they are vulnerable to damage due to head trauma. Orbitofrontal cortex (OFC) integrity is important for olfaction and aspects of behavioral regulation. We measured olfactory identification ability in a sample of impulsive violent offenders to determine its associations with history of traumatic brain injury (TBI) and a range of neuropsychiatric indices, including proxies for cognitive ability, impulsivity and social connectedness.

Methods

Male participants were drawn from the ReINVEST study, a randomized controlled trial of sertraline to reduce recidivism in violent impulsive offenders. Criteria for participation in the study included a minimum age of 18 years, a documented history of two or more violent offenses, and a score of 70 or above on the Barratt Impulsiveness Scale (BIS-11). The 16-item "Sniffin sticks" (SS) odor identification test (OI) was administered as were standardized questionnaires regarding previous TBI, additional measures to screen cognition [word reading test of the Wechsler Individuals Achievement Test (WIAT), social connectedness (the Duke Social Support Scale), and a range of other neuropsychiatric conditions or symptoms]. The sample SS scores were compared against published age-specific norms. Univariate and multivariate analyses were performed with SS score (linear regression, within those without hyposmia) or hyposmia (logistic regression) as the outcome.

Results

The mean OI scores were lower than population norms and 16% of participants were classified as hyposmic. Univariate analyses showed associations of SS score with age, WIAT score, impulsivity, TBI and TBI severity, social connectedness, childhood sexual abuse, suicidality and current use of heroin. In multivariate analyses, age, TBI severity and WIAT remained as significant independent predictors of SS score (within the normosmic range) or hyposmia (logistic regression).

Conclusion

Olfactory performance was associated with multiple behavioral phenomena in a pattern that would be consistent with this serving as a proxy for orbitofrontal functioning. As such, OI testing may have utility in further studies of offenders. In future, we will examine whether olfactory score predicts recidivism or response to the administration of sertraline, in terms of reducing recidivism.

Self-reported traumatic brain injury in a sample of impulsive violent offenders: neuropsychiatric correlates and possible "dose effects"

Background

Traumatic brain injury (TBI) is a major public health problem that may be associated with numerous behavioral problems, including impulsivity, aggression and violence. Rates of self-reported TBI are high within offender populations, but the extent to which TBI is causally implicated in causing illegal behavior is unclear. This study examined the psychological and functional correlates of histories of traumatic brain injury in a sample of impulsive violent offenders.

Methods

Study participants, all men, had been recruited to participate in a randomized controlled trial of sertraline to reduce recidivism. Study entry criteria were an age of at least 18 years, a documented history of two or more violent offenses and a score of 70 or above on the Barratt Impulsiveness Scale. An extensive list of standardized questionnaires was administered to obtain information on previous TBI and other neuropsychiatric conditions or symptoms.

Results

In the sample of 693 men, 66% were aged between 18 and 35 years old, and 55% gave a history of TBI ("TBI+"). Overall, 55% of study participants reported at least one TBI. High levels of neuropsychiatric symptomatology were reported. In 75% of TBI+ individuals, their most severe TBI (by self-report) was associated with loss of consciousness (LOC) < 30 min. Compared to TBI- (those without history of TBI) participants, TBI+ individuals were more impulsive (Eysenck Impulsivity), irritable, angry, and reported higher levels of assaultive behavior, depressive symptomology, alcohol use disorder, suicidal ideation, suicide attempts, and lower quality of life. Potential "dose effects" of TBI severity and frequency in terms of neuropsychiatric symptomatology were identified.

Conclusion

Like other studies of offender populations, single and multiple TBIs were very common. The associations of TBI, TBI severity, and TBI frequency (i.e., TBI "burden") with adverse neuropsychiatric phenomena suggest TBI contributes importantly to offender morbidity but the select nature of the sample and cross-sectional study design constrain the interpretation of these findings.

Behavioral and Psychiatric Symptoms in Patients with Severe Traumatic Brain Injury: A Comprehensive Overview

Traumatic brain injury (TBI) is defined as an altered brain structure or function produced by an external force. Adults surviving moderate and severe TBI often experience long-lasting neuropsychological and neuropsychiatric disorders (NPS). NPS can occur as primary psychiatric complications or could be an exacerbation of pre-existing compensated conditions. It has been shown that changes in behavior following moderate to severe TBI have a prevalence rate of 25-88%, depending on the methodology used by the different studies. Most of current literature has found that cognitive behavioral and emotional deficit following TBI occurs within the first six months whereas after 1-2 years the condition becomes stable. Identifying the risk factors for poor outcome is the first step to reduce the sequelae. Patients with TBI have an adjusted relative risk of developing any NPS several-fold higher than in the general population after six months of moderate-severe TBI. All NPS features of an individual's life, including social, working, and familiar relationships, may be affected by the injury, with negative consequences on quality of life. This overview aims to investigate the most frequent psychiatric, behavioral, and emotional symptoms in patients suffering from TBI as to improve the clinical practice and tailor a more specific rehabilitation training.

Quality of life implications for elevated trait impulsivity in people with Parkinson's disease

BACKGROUND

Several non-motor features of Parkinson's disease (PD) are known to adversely affect patient health-related quality of life (HRQL). However, the specific impact of neuropsychiatric complications, such as impulsive behaviour, is yet to be elucidated.

OBJECTIVES

The present cross-sectional, observational study aimed to investigate the effects of heightened trait impulsivity on HRQL in individuals with PD.

METHODS

A total of 322 people with idiopathic PD were sequentially recruited from Movement Disorder clinics across Australia. Trait impulsivity in patients was determined by Barratt's Impulsiveness Scale Version 11 (BIS-11), and grouped into tertiles (low, medium, and high). Patient HRQL was determined by the 39-item Parkinson's Disease Questionnaire (PDQ-39), complemented by the Cambridge Behavioural Inventory-Revised (CBI-R) indicating caregivers' perception of patient HRQL.

RESULTS

When total BIS-11 scores were grouped into tertiles, patient perceived and caregiver-perceived HRQL were 1.7-fold (p < .001) and 2.2-fold (p < .001) worse in the high BIS-11 group when compared to patients in the low group. Univariate analysis revealed significant associations between second-order attentional (p < .001) and non-planning (p < .001) impulsivity domains with PDQ-39 scores. When controlling for confounding demographic and clinical variables, a multivariate linear regression model revealed second-order attentional impulsivity was independently predictive of poor patient perceived HRQL (p < .001).

CONCLUSION

These findings suggest that increasing trait impulsivity is significantly associated with patient perceived HRQL in PD. Improved knowledge and recognition of subclinical impulsivity may guide clinicians' treatment and reduce disease burden for patients experiencing PD symptoms.

Reduction of symptom after a combined behavioral intervention for reward sensitivity and rash impulsiveness in internet gaming disorder: A comparative study

Impulsivity is both a core symptom and a key psychological mechanism in Internet Gaming Disorder (IGD), and therefore interventions for impulsivity in IGD have both theoretical and practical value. However, previous related interventions only tended to focus on a single factor of impulsivity and achieved inconsistent results. In this study, based on the theory of two-factor model of impulsivity (reward sensitivity and rash impulsiveness), four groups of IGD subjects were recruited to investigate whether there were different effects of single rash impulsiveness or reward sensitivity intervention versus a combined intervention. By comparing the different factors of impulsivity of the four groups before and after a 15-day intervention, the results showed that: (1) compared with the control group, subjects in the Go/No-go training group only had a significantly lower level of rash impulsiveness, subjects in the Stimulus-Response Compatibility (SRC) training group only had a significantly lower level of reward sensitivity, and subjects in the combined training group had significantly lower levels of both impulsivity; (2) among the three intervention groups, only the subjects in the combined training group had significantly lower IGD scores in the follow-up measure. This study indicated that the behavioral training of Go/No-go and SRC were effective in improving rash impulsiveness and reward sensitivity in IGD, respectively, but the intervention effect of the combined training was better than that of the single training.

Impulsivity Trait Profiles in Patients With Cerebellar Ataxia and Parkinson Disease

BACKGROUND AND OBJECTIVES

Individuals with cerebellar ataxia (CA) can develop impulsive behavioral symptoms, often resulting in negative interpersonal consequences, detrimentally affecting their quality of life. Limited evidence exists concerning impulsivity in CA and its associated behavioral changes. We assessed impulsive traits in CA using the Barratt Impulsivity Scale (BIS-11) and compared them with those of Parkinson disease (PD) to investigate the differences in the impulsive trait profiles between CA and PD.

METHODS

We conducted a dual-center cross-sectional study with individuals with CA and PD enrolled through consecutive sampling from movement disorders clinics at Columbia University Medical Center and Vanderbilt University Medical Center, respectively. Age-matched controls were recruited at the respective institutions. Participants were excluded if they had prior or comorbid neurologic and psychiatric diseases known to be associated with impulsivity. All participants completed the BIS-11 questionnaire as a measure of impulsive traits. We used a general linear model and a least absolute shrinkage and selection operation regression to compare the total, subscale, and individual items of the BIS-11 scores between groups. Subgroup analyses were performed to isolate cerebellar contributions to impulsivity from potential effects of extracerebellar pathology and dopaminergic dysfunction or medications.

RESULTS

A total of 190 participants-90 age-matched controls, 50 participants with CA, and 50 with PD-completed the assessments. Persons with CA reported 9.7% higher BIS-11 scores than controls (p < 0.001), while persons with PD reported 24.9% higher scores than controls (p < 0.001). In CA, the most affected domain of impulsivity was nonplanning. In contrast, persons with PD noted greater impulsivity across the nonplanning, attentional, and motor domains.

DISCUSSION

Impulsivity in CA is uniquely driven by the nonplanning trait, unlike in PD. This suggests that the cerebellum and basal ganglia may differentially govern impulsive behaviors with the cerebellum contributing to the brain circuitry of impulsivity in a domain-specific manner.

The prevalence, predictors, associated symptoms, and outcomes of social disinhibition following moderate-to-severe TBI: A scoping review of quantitative evidence

The present study aimed to map existing quantitative evidence of research related to the nature of social disinhibition following moderate-to-severe traumatic brain injury (TBI), with a specific focus on its prevalence, predictors, associated symptoms and outcomes in studies that met minimal methodological criteria. We conducted a scoping review of the literature following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) extension for Scoping Reviews (PRISMA-ScR). Seventeen peer-reviewed articles including 1440 participants met the inclusion criteria and were included in the qualitative synthesis. Results of the study indicate that social disinhibition is a common and significant consequence of moderate-to-severe TBI with its prevalence estimates ranging from 21% to 32%. Inappropriate sexual behavior appears to be more prevalent in men and younger survivors. Rule-breaking/perseverative errors in fluency tests are significantly associated with social disinhibition. The perceived burden of caregivers of people with TBI is a very common outcome. An interesting finding was an association between higher social disinhibition and higher emotional empathy levels. However, similarly to many potential predictors, this was only found in a single study and therefore requires further investigation. Some common methodological flaws are discussed, such as the use of non-probability sampling, lack of sample size justification or not including a control group. Due to the heterogeneity of measures used to assess social disinhibition in the reviewed articles, conducting a meta-analysis was not possible. In conclusion, social disinhibition is a significant consequence of moderate-to-severe TBI, as it impacts both the TBI survivor and their family/caregivers. The present study extends the scope of the prior overview by offering a clearer picture of social disinhibition after surviving moderate-to-severe TBI, as it focuses on studies with strong methodology and validated measures. It also assesses potential predictors other than executive dysfunction, such as demographics and injury characteristics.

Traumatic Brain Injury, Abuse, and Poor Sustained Attention in Youth and Young Adults Who Previously Experienced Foster Care

Youth and young adults who previously experienced foster care are prone to negative life events, such as physical injuries, and adverse childhood experiences (ACE), such as abuse, neglect, and household dysfunction. The purpose of the present study was to identify the prevalence of traumatic brain injury (TBI), ACE, and poor sustained attention and the associations of these events in this group of vulnerable persons. Participants completed standardized questionnaires on the prevalence of self-reported TBI (TBI) and ACE and performed the Sustained Attention to Response Task (SART) test to measure sustained attention. Chi-squared and Kruskal-Wallis rank-sum tests were used to assess demographic differences and associations between TBI and ACE. Sustained attention was assessed using analysis of variance and linear modeling. Seventy-one participants-46 youth and young adults who previously experienced foster care (vulnerable group) and 25 age-matched healthy controls-completed the standardized questionnaires. Analyses indicated that vulnerable participants reported markedly higher rates of TBI and ACE than healthy controls. Vulnerable persons with TBI reported significantly higher Total ACE scores (p = 0.02), were more likely to have a history of family dysfunction (p = 0.02), and were more likely to have lived with a mentally ill guardian (p = 0.01) than vulnerable persons with no TBI. TBI was significantly associated with Total Errors (p = 0.001 and p = 0.02) and Omission Errors (p < 0.001 and p = 0.01) in all participants and in vulnerable participants, respectively, after adjusting for education level.

The role of impulsivity in neurorehabilitation: A prospective cohort study of a potential cognitive biomarker for fall risk?

BACKGROUND

Executive dysregulation and impulsivity can both predispose individuals to risk-prone actions. Although the risk of falls is well established in people with poor executive function, its association to impulsivity is less clear.

PURPOSE

To describe and assess the prognostic capabilities of the relationship between impulsivity, executive function, functional capability, and falls in the in-patient neurorehabilitation population.

MATERIALS AND METHODS

A prospective cohort study in a 26-bed neurorehabilitation unit in London, recruiting 121 patients, of whom 94 were deemed eligible for inclusion. Cognitive-behavioural assessment was undertaken using the short (16-item) version of the Urgency-Premeditation-Perseverance-Sensation Seeking-Positive Urgency (UPPS) impulsive behaviour scale, and the Trail Making Test (TMT). Patients also underwent a functional assessment at admission and discharge using the UK Functional Independence and Assessment Measure tool (FIM + FAM). The main outcome of interest was falling during an in-patient episode, which are routinely recorded in a computerized registry of adverse incidents.

RESULTS

Measurements of impulsivity (based on the UPPS-Short form) and executive function (based on the Trail Making Test) were not found to be significantly associated with functional improvement, or risk of falling. Predictive modelling experiments demonstrated that neither of the aforementioned results were capable of identifying individuals at risk of falling more accurately than an informed guess.

CONCLUSION

Where impulsivity is present, measurement using structured tools such as the UPPS may be informative to guide individualized rehabilitation programmes; however, its usefulness as the basis of risk prediction models for falls is less likely given the results of this study.

The Relationship between Sport-Related Concussion and Sensation-Seeking

Sensation-seeking, or the need for novel and exciting experiences, is thought to play a role in sport-related concussion (SRC), yet much remains unknown regarding these relationships and, more importantly, how sensation-seeking influences SRC risk. The current study assessed sensation-seeking, sport contact level, and SRC history and incidence in a large sample of NCAA collegiate athletes. Data included a full study sample of 22,374 baseline evaluations and a sub-sample of 2037 incident SRC. Independent samples t-test, analysis of covariance, and hierarchical logistic regression were constructed to address study hypotheses. Results showed that (1) among participants without SRC, sensation-seeking scores were higher in athletes playing contact sports compared to those playing limited- or non-contact sports (p < 0.001, R² = 0.007, η²_p = 0.003); (2) in the full study sample, a one-point increase in sensation-seeking scores resulted in a 21% greater risk of prior SRC (OR = 1.212; 95% CI: 1.154-1.272), and in the incident SRC sub-sample, a 28% greater risk of prior SRC (OR = 1.278; 95% CI: 1.104-1.480); (3) a one-point increase in sensation-seeking scores resulted in a 12% greater risk of incident SRC among the full study sample; and (4) sensation-seeking did not vary as a function of incident SRC (p = 0.281, η²_p = 0.000). Our findings demonstrate the potential usefulness of considering sensation-seeking in SRC management.

Neuropsychiatric Presentations due to Traumatic Brain Injury in Cognitively Normal Older Adults

Neuropsychiatric symptoms (NPS) are common sequelae of traumatic brain injuries (TBI) among adults. However, little is known about NPS associated with a history of TBI in adults relative to adults without a history of TBI and to what extent NPS may be modulated by sex and other factors. Using the National Alzheimer's Coordinating Center Uniform Data Set, we examined the association between Neuropsychiatric Inventory-Questionnaire (NPI-Q) scores in cognitively normal older adults with and without a history of TBI. A binomial logistic regression model was used to examine NPI-Q domains in adults with a history of TBI (n = 266) versus without a history of TBI (n = 1508). History of TBI, sex, age, and body mass index were used as covariates. Adults with a history of TBI had a greater probability of exhibiting agitation, anxiety, apathy, disinhibition and aberrant motor behavior relative to adults without a history of TBI. In terms of sex differences, males with and without a history of TBI had an increased likelihood of agitation, apathy, disinhibition, and apnea, whereas females had an increased likelihood of anxiety and insomnia relative to males. Our study confirms that history of TBI is associated with an increased prevalence of specific NPS, including agitation, anxiety, apathy, disinhibition, and aberrant motor behavior. Given that the aforementioned NPS are linked through different pathways, damage to any of them may cause an alteration in behavior. As well, NPS appear to be modulated by sex, with symptoms differing between males and females. Our research suggests future studies examining NPS sequelae of TBI should adjust for sex.

Basal impulses: findings from the last twenty years on impulsivity and reward pathways using deep brain stimulation

INTRODUCTION

Deep brain stimulation (DBS) is an important treatment modality for movement disorders. Its role in tasks and processes of higher cortical function continues to increase in importance and relevance. This systematic review investigates the impact of DBS on measures of impulsivity.

EVIDENCE ACQUISITION

A total of 45 studies were collated from PubMed (30 prospective, 8 animal, 4 questionnaire-based, and 3 computational models), excluding case reports and review articles. Two areas extensively studied are the subthalamic nucleus (STN) and nucleus accumbens (NAc).

EVIDENCE SYNTHESIS

While both are part of the basal ganglia, the STN and NAc have extensive connections to the prefrontal cortex, cingulate cortex, and limbic system. Therefore, understanding cause and treatment of impulsivity requires understanding motor pathways, learning, memory, and emotional processing. DBS of the STN and NAc shell can increase objective measures of impulsivity, as measured by reaction times or reward-based learning, independent from patient insight. The ability for DBS to treat impulse control disorders, and also cause and/or worsen impulsivity in Parkinson's disease, may be explained by the affected closely-related neuroanatomical areas with discrete and sometimes opposing functions.

CONCLUSIONS

As newer, more refined DBS technology emerges, large-scale prospective studies specifically aimed at treatment of impulsivity disorders are needed.

Altruistic Punishment and Impulsivity in Parkinson's Disease: A Social Neuroscience Perspective

Non-motor symptoms of Parkinson's disease (PD) are of increasing interest in clinical and psychological research. Disinhibition-the inability to inhibit inappropriate behavior-leads to social and emotional impairments, including impulsive behavior and disregard for social conventions and decision-making behavior. In recent years, the latter has been investigated using economic exchanges during social interactions. Altruistic punishment-to punish someone who violates group norms even if it foresees a personal cost-is one of the most useful and fruitful paradigms; it allows to maintain a cooperation system within social groups. Alterations of this cognitive ability negatively impact the quality of life of the individual and social stability. Social neuroscience has suggested association between impulsive behaviors and altruistic punishment. Neuroimaging research aimed at exploring functional networks and intrinsic functional connectivity went in this direction. To date, little is known about these issues in neurodegenerative diseases such as PD. Dopamine replacement treatment and dopamine-agonists have been associated with impulse-control disorder and impulsive-compulsive behavior able to affect social decision-making. Frontal-executive dysfunction determines an alteration of social functioning through a mechanism of subversion of online action-monitoring, which associates disinhibition with volition. Genetic polymorphisms, alterations of the nigro-striatal substance, and impairment in the medial prefrontal cortex and in the Default mode network (DMN) seem to be able to explain these mechanisms. This theoretical perspective article aims to present these topics in order to encourage an interdisciplinary discussion capable of generating new research and developing rehabilitative intervention to improve social decision-making in PD patients.

Clarifying ADHD and Sluggish Cognitive Tempo Item Relations with Impairment: A Network Analysis

Despite the pervasive nature of various forms of impairment associated with attention-deficit/hyperactivity disorder (ADHD), the precise nature of their associations with ADHD and related sluggish cognitive tempo (SCT), particularly at the heterogeneous item level, remains ambiguous. Using innovative network analysis techniques, we sought to identify and examine the concurrent validity of ADHD and SCT bridge items (i.e., those demonstrating the most robust relations with various forms of impairment) with respect to Overall, Home-School, and Community-Leisure impairment domains. Parents of a nationally representative sample of 1742 children (50.17% male) aged 6-17 years completed rating scales of ADHD, SCT, and impairment. Assessment of Bridge Expected Influence suggested eight bridge items primarily from impulsive and Task Completion (i.e., overlapping SCT and inattentive) domains that demonstrated relations with impairment in school performance, completing chores at home, interacting with family members, following rules, and playing sports. Sum scores only including bridge items exhibited relations with Overall, Home-School, and Community-Leisure impairment domains comparable to that of sum scores including all items. Bridge impairment areas were generally consistent across "Childhood" (6-11 years) and "Adolescence" (12-17 years). Problems listening and slowness emerged as bridge items in Childhood, whereas difficulties following through on instructions, problems waiting one's turn, and social withdrawal emerged in Adolescence. Given the comparable validity of ADHD- and SCT-related bridge items versus all items, bridge items, together, may be the most efficient indicators of impairment. Further clarification is needed across development to inform personalized assessment and intervention protocols that account for item-level heterogeneity in ADHD, SCT, and impairment phenotypes.

Mosaic trisomy 20 and mitigation in capital crimes sentencing: A review and case report

Trisomy 20 is a genetic abnormality in which individuals have an extra copy of chromosome 20. Complete trisomy 20 is rare and believed to be incompatible with life. A mosaic form of trisomy 20, in which only some cells or tissues contain the extra chromosome, is a relatively commonly encountered chromosomal abnormality found during prenatal testing, and c. 90% result in a normal phenotype. However, despite the absence of a consistent phenotype, certain findings have been reported across multiple cases of mosaic trisomy 20. These include an array of morphological findings, developmental delays, and learning disabilities. Beyond physical manifestations, a wide range of developmental and learning delays have also been reported. In this work, we provide an overview of the trisomy 20 literature and a case report of a young adult male with mosaic trisomy 20 who committed homicide. His developmental and life history, eventual diagnosis of mosaic trisomy 20, similarities and differences in his condition compared with prior research findings, and potentially new phenotypic findings associated with trisomy 20 that he manifested (childhood visual hallucinations, self-injury, polydactyly) are presented. Additionally, the potential role of this genetic diagnosis in his neuropsychiatric history and its successful application as a mitigating factor at his capital sentencing trial are described. We did not identify other similar cases during our search of major scientific and legal databases. As a backdrop, the use of genetics in criminal trials is on the rise, and courts are increasingly likely to accept behavioral genetics evidence; therefore, it is crucial that the legal system is well acquainted with the opportunities and limitations of these approaches.

Corticostriatal Hyperactivation to Reward Presentation in Individuals With TBI With High Depressive Symptomatology: A Pilot Study

OBJECTIVE

To examine the impact of depression on neural mechanisms associated with outcome processing (rewarding and punishing outcomes) in persons with traumatic brain injury (TBI).

SETTING

Kessler Foundation's Rocco Ortenzio Neuroimaging Center.

PARTICIPANTS

A total of 16 adults with moderate to severe TBI.

MAIN MEASURES

Chicago Multiscale Depression Inventory (CMDI); Behavioral Inhibition/Behavioral Activation Scale (BIS/BAS); functional MRI of the head while performing a gambling task, with a reward (+$1.00) and punishment (-$0.50).

RESULTS

Individuals with TBI reporting high depressive symptomatology exhibited increased activation in the ventromedial prefrontal cortex (VMPFC) and striatum during presentation of rewarding outcomes compared with individuals with TBI reporting low depressive symptomatology. Punishing outcome presentation was not associated with any change in brain activation. No differences in volume of the striatum and VMPFC were observed between groups.

CONCLUSIONS

Current findings provide the first evidence of differences in neural mechanisms underlying outcome processing between individuals with TBI with and without depression. The results suggest that depressive symptomatology might have a different effect on individuals with TBI than what is typically observed in individuals without TBI reporting with depression, with the possibility of rewards becoming more reinforcing as depressive symptomatology increases. Future studies should explore the potential implications of behavioral responses to rewards and punishments in TBI and how they can affect rehabilitation approaches and activities of daily living.

Long-Term Effects of Traumatic Brain Injury on Anxiety-Like Behaviors in Mice: Behavioral and Neural Correlates

Traumatic brain injury (TBI) has been frequently linked to affective disorders such as anxiety and depression. However, much remains to be understood about the underlying molecular and signaling mechanisms that mediate affective dysfunctions following injury. A lack of consensus in animal studies regarding what the affective sequelae of TBI are has been a major hurdle that has slowed progress, with studies reporting the full range of effects: increase, decrease, and no change in anxiety following injury. Here, we addressed this issue directly by investigating long-term anxiety outcomes in mice following a moderate to severe controlled cortical impact (CCI) injury using a battery of standard behavioral tests-the open field (OF), elevated zero maze (EZM), and elevated plus maze (EPM). Mice were tested on weeks 1, 3, 5 and 7 post-injury. Our results show that the effect of injury is time- and task-dependent. Early on-up to 3 weeks post-injury, there is an increase in anxiety-like behaviors in the elevated plus and zero mazes. However, after 5 weeks post-injury, anxiety-like behavior decreases, as measured in the OF and EZM. Immunostaining in the basolateral amygdala (BLA) for GAD, a marker for GABA, at the end of the behavioral testing showed the late decrease in anxiety behavior was correlated with upregulation of inhibition. The approach adopted in this study reveals a complex trajectory of affective outcomes following injury, and highlights the importance of comparing outcomes in different assays and time-points, to ensure that the affective consequences of injury are adequately assessed.

Impulse control disorders in patients with prolactinoma receiving dopamine agonist therapy: a prospective study with 1 year follow-up

OBJECTIVE

To assess prospectively the prevalence of impulse control disorders (ICD), psychiatric symptoms, and their clinical correlates in patients with prolactinoma receiving dopamine agonists (DA) in comparison to those with non-functioning pituitary adenomas (NFA) and healthy controls (HC).

METHODS

A total of 25 patients with prolactinoma, 31 with NFA, and 32 HCs were included in the study. All patients and controls were screened for the presence of ICDs and other psychiatric disorders using revised version of Minnesota Impulsive Disorders Interview (MIDI-R), Barratt Impulsiveness Scale (BIS-11), Symptom Check List (SCL-90-R) questionnaire and Beck Depression Inventory (BDI), and Beck Anxiety Inventory (BAI).

RESULTS

We detected two new cases (8%) of ICD associated with DAs. Both cases presented with hypersexuality, which reversed totally or decreased upon discontinuation of the drug. The re-challenge of the DA in a smaller dose has led to either no symptoms or weaker symptoms than before. There was an increase in the number of patients who screened positive on obsession, interpersonal sensitivity, paranoid ideation, and additional items subscales of SCL-90-R in comparison to HCs at the end of the study period (p < 0.05 for all). Likewise, cumulative DA dose was positively correlated to obsession, interpersonal sensitivity, paranoid ideation, hostility, phobic anxiety subscales, and GSI scores of SCL-90-R (p < 0.05 for all).

CONCLUSIONS

DAs are associated with a small but substantial short-term risk of ICD development and a broad range of psychiatric symptoms in patients with prolactinoma receiving DAs.

Gambling, motor cautiousness, and choice impulsivity: An experimental study

BACKGROUND

Impulsivity is currently more commonly regarded as multifaceted, comprising both motor and cognitive subdomains. However, it is less clear how distinct these subdomains are, and the extent to which they interact and draw upon the same psychological resources.

METHODS

The present experiment comprised 70 regular (non-problem) gamblers, and investigated the potential to induce impulsivity transfer effects within an electronic gambling context. Original and existing harm-minimization approaches were tested for their efficacy in inducing motor cautiousness during an electronic slot machine simulation. Participants were exposed to a forced discriminatory motor choice procedure, or pop-up responsible gambling messages that either contained emotive or non-emotive responsible gambling content. The subsequent impact these interventions had on delay discounting and reflection impulsivity was also measured using the 27-item Monetary Choice Questionnaire and Information Sampling Task, respectively.

RESULTS

Findings demonstrated that only original harm-minimization approaches, which force the gambler to engage in discriminatory motor choice procedures during gambling, were successful in inducing motor cautiousness. However, both the discriminatory choice procedure and emotive message harm-minimization approaches were successful in facilitating cognitive choice, even though the emotive message intervention was unsuccessful in facilitating motor response inhibition, suggesting both an indirect motor cautiousness route, and a more direct route to improved cognitive choice during gambling.

CONCLUSION

This study demonstrated that decision-making during gambling can be improved by making simple structural changes to slot machine platforms, by encouraging active engagement in motor processes, which result in a transfer of cautiousness to wider cognitive domains.

Neuroimaging of Subacute Brain Inflammation and Microstructural Changes Predicts Long-Term Functional Outcome after Experimental Traumatic Brain Injury

There is currently a lack of prognostic biomarkers to predict the different sequelae following traumatic brain injury (TBI). The present study investigated the hypothesis that subacute neuroinflammation and microstructural changes correlate with chronic TBI deficits. Rats were subjected to controlled cortical impact (CCI) injury, sham surgery, or skin incision (naïve). CCI-injured (n = 18) and sham-operated rats (n = 6) underwent positron emission tomography (PET) imaging with the translocator protein 18 kDa (TSPO) radioligand [¹⁸F]PBR111 and diffusion tensor imaging (DTI) in the subacute phase (≤3 weeks post-injury) to quantify inflammation and microstructural alterations. CCI-injured, sham-operated, and naïve rats (n = 8) underwent behavioral testing in the chronic phase (5.5-10 months post-injury): open field and sucrose preference tests, two one-week video-electroencephalogram (vEEG) monitoring periods, pentylenetetrazole (PTZ) seizure susceptibility tests, and a Morris water maze (MWM) test. In vivo imaging revealed pronounced neuroinflammation, decreased fractional anisotropy, and increased diffusivity in perilesional cortex and ipsilesional hippocampus of CCI-injured rats. Behavioral analysis revealed disinhibition, anhedonia, increased seizure susceptibility, and impaired learning in CCI-injured rats. Subacute TSPO expression and changes in DTI metrics significantly correlated with several chronic deficits (Pearson's |r| = 0.50-0.90). Certain specific PET and DTI parameters had good sensitivity and specificity (area under the receiver operator characteristic [ROC] curve = 0.85-1.00) to distinguish between TBI animals with and without particular behavioral deficits. Depending on the investigated behavioral deficit, PET or DTI data alone, or the combination, could very well predict the variability in functional outcome data (adjusted R² = 0.54-1.00). Taken together, both TSPO PET and DTI seem promising prognostic biomarkers to predict different chronic TBI sequelae.

On the Link Between Emotionally Driven Impulsivity and Aggression: Evidence From a Validation Study on the Dutch UPPS-P

The UPPS-P seems to be a promising instrument for measuring different domains of impulsivity in forensic psychiatric patients. Validation studies of the instrument however, have been conducted only in student groups. In this validation study, three groups completed the Dutch UPPS-P: healthy student ( N = 94) and community ( N = 134) samples and a forensic psychiatric sample ( N = 73). The five-factor structure reported previously could only be substantiated in a confirmatory factor analysis over the combined groups but not in the subsamples. Subgroup sample sizes might be too small to allow such complex analyses. Internal consistency, as assessed by Cronbach's alpha, was high on most subscale and sample combinations. In explaining aggression, especially the initial subscale negative urgency (NU) was related to elevated scores on self-reported aggression in the healthy samples (student and community). The current study is the second study that found a relationship between self-reported NU and aggression highlighting the importance of addressing this behavioural domain in aggression management therapy.

Development and content validity of the behavioral assessment screening tool (BASTβ)

PURPOSE

Develop and establish the content validity of the Behavioral Assessment Screening Tool (BAST_β), a self-reported measure of behavioral and emotional symptoms after traumatic brain injury.

METHODS

This was an assessment development study, including two focus groups of individuals with traumatic brain injury (n = 11) and their family members (n = 10) and an expert panel evaluation of content validity by experts in traumatic brain injury rehabilitation (n = 7). We developed and assessed the Content Validity Index of the BAST_β.

RESULTS

The BAST_β initial items (n = 77) corresponded with an established conceptual model of behavioral dysregulation after traumatic brain injury. After expert panel evaluation and focus group feedback, the final BAST_β included 66 items (60 primary, 6 branching logic) rated on a three-level ordinal scale (Never, Sometimes, Always) with reference to the past two weeks, and an Environmental Context checklist including recent major life events (n = 23) and four open-ended questions about environmental factors. The BAST_β had a high Content Validity Index of 89.3%.

CONCLUSION

The BAST_β is a theoretically grounded, multidimensional self-reported assessment of behavioral dysregulation after traumatic brain injury, with good content validity. Future translation into mobile health modalities could improve effectiveness and efficiency of long-term symptom monitoring post-traumatic brain injury. Future work will establish and validate the factor structure, internal consistency reliabilities and other validities of the BAST. Implications for Rehabilitation Behavioral problems after traumatic brain injury is one of the strongest contributing factors to poor mood and community integration outcomes after injury. Behavior is complex and multidimensional, making it a challenge to measure and to monitor long term. The Behavioral Assessment Screening Tool (BAST) is a patient-oriented outcome assessment developed in collaboration with individuals with traumatic brain injury, their care partners, and experts in the field of traumatic brain injury rehabilitation to be relevant and accessible for adults with traumatic brain injuries. The BAST is a long-term monitoring and screening tool for community-dwelling adults with traumatic brain injuries, to improve identification and management of behavioral and emotional sequelae.

Roadway Aggression Among Drivers and Passengers With or Without a History of Traumatic Brain Injury

OBJECTIVE

This study examined the association between roadway aggression and traumatic brain injury (TBI) among drivers and passengers who reside in the province of Ontario, Canada.

METHODS

Data were based on a 3-year cumulated cross-sectional sample of 6,048 adults aged 18 years and older who were surveyed by telephone. The outcome in this study was road rage in the form of verbal/gestural or physical aggression toward other road users and/or their vehicle.

RESULTS

Driving status, history of TBI, age, gender, education, and the interaction between history of TBI and education significantly predicted roadway aggression. Odds ratios (ORs) for roadway aggression were significantly higher among drivers ( OR= 2.65) compared to passengers, between 2 and 4.5 times higher among individuals aged 18-64 years old compared to those older than 65 years, higher among adults with TBI (OR = 2.05) than without, and men (OR = 1.54) than women. Among respondents with lowest, but not highest, levels of education, roadway aggression was predicted by a history of TBI.

CONCLUSION

This is the first population-based study to compare rates of roadway aggression between drivers and passengers with and without TBI. Research to understand these differences will be important for roadway aggression prevention efforts and policy.

A multifactorial and integrative approach to impulsivity in neuropsychology: insights from the UPPS model of impulsivity

Risky and excessive behaviors, such as aggressive and compulsive behaviors, are frequently described in patients with brain damage and have dramatic psychosocial consequences. Although there is strong evidence that impulsivity constitutes a key factor at play in these behaviors, the literature about impulsivity in neuropsychology is to date scarce. In addition, examining and understanding these problematic behaviors requires the assumption that impulsivity is a multidimensional construct. Consequently, this article aims at shedding light on frequent risky and excessive behaviors in patients with brain damage by focusing on a unified, comprehensive, and well-validated model, namely, the UPPS model of impulsivity. This model considers impulsivity as a multidimensional construct that includes four facets: urgency, (lack of) premeditation, (lack of) perseverance, and sensation seeking. Furthermore, we discuss the psychological mechanisms underlying the dimensions of impulsivity, as well as the laboratory tasks designed to assess each mechanism and their neural bases. We then present a scale specifically designed to assess these four dimensions of impulsivity in patients with brain damage and examine the data regarding this multidimensional approach to impulsivity in neuropsychology. This review supports the need to adopt a multifactorial and integrative approach toward impulsive behaviors, and the model presented provides a valuable rationale to disentangle the nature of brain systems and mechanisms underlying impulsive behaviors in patients with brain damage. It may also foster further relevant research in the field of impulsivity and improve assessment and rehabilitation of impulsive behaviors in clinical settings.

Cognitive and neurobehavioral symptoms in patients with non-metastatic prostate cancer treated with androgen deprivation therapy or observation: A mixed methods study

BACKGROUND

Few studies have investigated prostate cancer patients' experiences of cognitive functioning or neurobehavioral symptoms (i.e., behavioral changes associated with neurological dysfunction) following androgen deprivation therapy (ADT).

METHODS

Semi-structured interviews conducted from the US by phone and in-person were used to explore and characterize the: 1) experience of cognitive and neurobehavioral functioning in non-metastatic prostate cancer patients undergoing ADT (n = 19) compared with patients who had not undergone ADT (n = 20); 2) perceived causes of cognitive and neurobehavioral symptoms; 3) impact of these symptoms on quality of life; and 4) strategies used to cope with or compensate for these symptoms. Neuropsychological performance was assessed to characterize the sample.

RESULTS

Overall, ADT patients experienced marginally more cognitive problems than non-ADT (nADT) patients even though there were no significant differences between groups in neuropsychological performance. ADT patients also experienced more declines in prospective memory and multi-tasking than nADT patients. Significant proportions of participants in both groups also experienced retrospective memory, attention and concentration, and information processing difficulties. With respect to neurobehavioral symptoms, more ADT patients experienced emotional lability and impulsivity (both aspects of disinhibition) than nADT patients. Among the causes to which participants attributed declines, both groups attributed them primarily to aging. A majority of ADT patients also attributed declines to ADT. For both groups, increased cognitive and neurobehavioral symptoms negatively impacted quality of life, and most participants developed strategies to ameliorate these problems.

CONCLUSION

ADT patients are more vulnerable to experiencing specific cognitive and neurobehavioral symptoms than nADT patients. This study highlights the importance of capturing: a) cognitive symptoms not easily detected using neuropsychological tests; b) neurobehavioral symptoms that can be confused with psychological symptoms, and c) causal beliefs that may affect how people cope with these symptoms. Effective interventions are needed to assist prostate cancer patients in managing these symptoms.

The effect of premorbid attention-deficit/hyperactivity disorder on neuropsychological functioning in individuals with acute mild traumatic brain injuries

INTRODUCTION

Mild traumatic brain injury (mTBI) is a frequent, yet undertreated condition that typically manifests with transient neurological and cognitive symptoms that resolve over the course of several weeks. In contrast, attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that presents initially in childhood but often persists into adulthood. mTBI and ADHD include overlapping symptomatology, making it difficult for clinicians to disentangle the sequelae of each condition when they co-occur in the same individual. We hypothesized that neuropsychological tests would be sensitive to preexisting ADHD in inpatients with acute mTBIs.

METHOD

We retrospectively examined the medical charts of 100 inpatients, aged 18-40 years (96% Caucasian; 77% male) with mTBIs in an acute care setting, half of whom had self-reported the presence of premorbid ADHD, and half of whom were matched controls. We analyzed group differences across neuropsychological tests of attention, processing speed, and executive functions, examined the profile ratings of independent, blinded, board-certified neuropsychologists, and correlated cognitive performance with time from traumatic injury to testing.

RESULTS

Individuals with premorbid ADHD (a) performed significantly worse than their matched counterparts on several tests of attention, processing speed, and working memory, and (b) were significantly more likely to produce profiles later rated as impaired by independent, board-certified clinical neuropsychologists. In addition, time from traumatic injury to testing was found to be negatively correlated with neurocognitive performance.

CONCLUSIONS

These findings (a) argue for the utility of a brief assessment of premorbid ADHD in the acute care of individuals with mTBIs and (b) provide clinicians with a barometer for gauging the relative contributions of premorbid ADHD to neuropsychological impairments in the neurocognitive profiles of individuals with mTBIs. Reported effect sizes will assist clinicians in accurately weighing the impact of premorbid ADHD when interpreting such profiles.

The Subthalamic Nucleus, Limbic Function, and Impulse Control

It has been well documented that deep brain stimulation (DBS) of the subthalamic nucleus (STN) to address some of the disabling motor symptoms of Parkinson's disease (PD) can evoke unintended effects, especially on non-motor behavior. This observation has catalyzed more than a decade of research concentrated on establishing trends and identifying potential mechanisms for these non-motor effects. While many issues remain unresolved, the collective result of many research studies and clinical observations has been a general recognition of the role of the STN in mediating limbic function. In particular, the STN has been implicated in impulse control and the related construct of valence processing. A better understanding of STN involvement in these phenomena could have important implications for treating impulse control disorders (ICDs). ICDs affect up to 40% of PD patients on dopamine agonist therapy and approximately 15% of PD patients overall. ICDs have been reported to be associated with STN DBS. In this paper we will focus on impulse control and review pre-clinical, clinical, behavioral, imaging, and electrophysiological studies pertaining to the limbic function of the STN.