Neurocognitive Measures Research Articles

The role of neurocognitive functioning, substance use variables and the DSM-5 severity scale in cocaine relapse: A prospective study

BackgroundThe severity of substance use disorder (SUD) is currently defined by the sum of DSM-5 criteria. However, little is known about the validity of this framework or the role of additional severity indicators in relapse prediction. This study aimed to investigate the relationship between DSM-5 criteria, neurocognitive functioning, substance use variables and cocaine relapse among inpatients with cocaine use disorder (CUD). Methods128 adults aged between 18 and 45 years were evaluated; 68 (59 males, 9 females) had CUD and 60 (52 males, 8 females) were healthy controls. For the group with CUD, the use of other substances was not an exclusion criterion. Participants were tested using a battery of neurocognitive tests. Cocaine relapse was evaluated 3 months after discharge. ResultsScores for attention span and working memory were worse in patients compared to controls. Earlier onset and duration of cocaine use were related to poorer inhibitory control and global executive functioning, respectively; recent use was related to worse performance in inhibitory control, attention span and working memory. More DSM-5 criteria at baseline were significantly associated with relapse. ConclusionsRecent cocaine use was the most predictive variable for neurocognitive impairments, while DSM-5 criteria predicted cocaine relapse at three months post treatment. The integration of neurocognitive measures, DSM-5 criteria and cocaine use variables in CUD diagnosis could improve severity differentiation. Longitudinal studies using additional biomarkers are needed to disentangle the different roles of severity indicators in relapse prediction and to achieve more individualized and effective treatment strategies for these patients.

Impact of physical activity in vascular cognitive impairment (AFIVASC): study protocol for a randomised controlled trial

BackgroundCognitive impairment and cerebrovascular pathology are both frequent with ageing. Cognitive impairment due to vascular pathology of the brain, termed vascular cognitive impairment (VCI), is one of the most frequent causes of cognitive impairment in elderly subjects. Thus far, VCI has no specific pharmacological treatment. Recent observational studies have suggested a protective effect of physical activity in cognition, but adequate randomised controlled trials (RCT) are lacking.MethodsAFIVASC is a multi-centre randomised controlled trial, with a 6-month intervention treatment and an additional follow-up of 6 months, that aims to estimate the impact of 6 months of moderate intensity physical activity on cognition (the primary outcome) at 6 and 12 months in subjects with VCI. Participants are community dwellers with criteria for VCI without dementia or who have had previous stroke or transient ischaemic attack (TIA). Patients may be self-referred or referred from a medical appointment. After confirming the inclusion criteria, a run-in period of 1 month is conducted to access adherence; only after that are subjects randomly assigned (using a computerised program blinded to clinical details) to two groups (intervention group and best practice usual care group). The intervention consists of three physical activity sessions of 60 min each (two supervised and one unsupervised) per week. The primary outcome is measured by the presence or absence of decline in cognitive status. Secondary outcomes include changes in neuro-cognitive measures, quality of life, and functional and motor status. Primary and secondary outcomes are evaluated at 6 and 12 months by investigators blinded to both intervention and randomisation. A required sample size of 280 subjects was estimated. Statistical analyses will include regression analysis with repeated measures. The study was approved by the Ethics Committee for Health of Centro Hospitalar de Lisboa Norte (ref. no. 1063/13) and by the Ethics Committee for Health of Centro Hospitalar do Porto CHP (ref. no. 2016.055(049-DEFI/048-CES)).DiscussionWe aim to show whether or not moderate physical activity has a beneficial impact on cognition, quality of life, motor, and functional status in people with vascular cognitive impairment, and to generate new insights on the applicability of implementing physical activity in this specific population.Trial RegistrationClinicalTrials.gov, NCT03578614 July 6, 2018.

Evaluating Motor Control Improves Discrimination of Adolescents with and without Sports Related Concussion

Disrupted motor performance is increasingly recognized as a critical sequela of concussion which may have relevance for diagnosis and treatment. In 17 adolescents with recent concussion and 20 never-concussed controls, we evaluated the discriminant ability of a commonly used neurocognitive measure compared to a motor subtle sign exam, which evaluates gait, balance, and fine and gross motor control. We found that the motor subtle sign exam had better discriminant ability than the neurocognitive measure, but combining both measures was superior to analyses with individual measures (Wilks’ ƛ = .297, p < .001). This supports that there is an added benefit of evaluating motor control along with neurocognitive capacities after suspected concussion to enhance diagnosis and treatment of injury.

Diffusion tensor imaging of neurocognitive profiles in a community cohort living in marginal housing

ObjectiveWe investigated white matter differences associated with distinct neurocognitive profiles derived from a large cohort of marginally housed persons with comorbid physical and mental illnesses. Our prior work identified three profile cluster groups: a high functioning group (Cluster 1), a low functioning group with relative strength in decision‐making (Cluster 3), and an intermediary group with a relative decision‐making weakness (Cluster 2). This study extends previous findings of cortical gray matter differences between these groups with evidence for putative neurodevelopmental abnormalities in the low cognitive functioning group (i.e., Cluster 3). We hypothesized that altered white matter diffusion would be associated with the lowest functioning neurocognitive profile and would be associated with previously observed gray matter differences.MethodParticipants from a socially impoverished neighborhood in Vancouver, Canada underwent neurocognitive evaluation and neuroimaging. We performed Tract‐Based Spatial Statistics using diffusion tensor imaging data from 184 participants to examine whole‐brain differences in white matter microstructure between cluster analytically derived neurocognitive profiles, as well as unitary neurocognitive measures. Correlations between frontal gray and white matter were also examined.ResultsCluster 3 showed increased diffusion in predominately bilateral frontal and interhemisphere tracts (vs. Clusters 1 and 2), with relatively greater diffusion in the left hemisphere (vs. Cluster 1). Differences in radial diffusivity were more prominent compared with axial diffusivity. A weak association between regional frontal fractional anisotropy and previously defined abnormalities in gyrification was observed.ConclusionsIn a socially marginalized sample, we established several patterns in the covariation of white matter diffusion and neurocognitive functioning. These patterns elucidate the neurobiological substrates and vulnerabilities that are apt to underlie functional impairments inherent to this complex and heterogeneous population.

Goal-Oriented Attention Self-Regulation (GOALS) training in older adults

Objectives: A common cognitive complaint of older adulthood is distractibility, or decline in ability to concentrate and maintain focus, yet few evidence-based interventions exist to address these deficits. We implemented s pilot trial of an evidence-based executive function training program, to investigate whether training in applied goal-directed attention regulation and problem solving would enhance executive control abilities in a sample of cognitively normal older adults with self-reported complaints of concentration problems.Method: Consecutively recruited participants were placed into small groups and randomized to either Goal-Oriented Attentional Self-Regulation training (GOALS; N = 15) or a closely matched Brain Health Education program (BHE; N = 15).Results: GOALS participants significantly improved on: neurocognitive measures of mental flexibility (p = 0.03, partial eta squared = 0.23); real-world setting functional performance measures of: task failures (p = 0.02, Cohen’s d = 0.88), task rule breaks (p = 0.02, Cohen’s d = 1.06), and execution (p = 0.04, Cohen’s d = 0.76); and in-lab functional assessment of goal-directed behaviour divergent thinking scale (p = 0.03, Cohen’s d = 0.95). All participants improved on a neurocognitive measure of planning (p = 0.01, partial eta squared = 0.031). BHE participants’ improvement over and above GOALS participants was limited to: rule adherence on the real world task (p = 0.04, Cohen’s d = 0.99), and evaluator rating (p = 0.03, Cohen’s d = 0.56), and average score (p = 0.02, Cohen’s d = 0.71) on the in-lab functional task.Conclusion: Participation in GOALS training can enhance executive control, and lead to real-world functional improvements, for cognitively normal older adults with self-reported attention difficulties.

Assessment of Neurocognitive Impairment and Speech Functioning Before Head and Neck Cancer Treatment

Head and neck cancer (HNC) and its treatment may negatively alter neurocognitive and speech functioning. However, the prevalence of neurocognitive impairment among patients with HNC before treatment is poorly studied, and the association between neurocognitive and speech functioning is unknown, which hampers good interpretability of the effect of HNC treatment on neurocognitive and speech function. To document neurocognitive functioning in patients with HNC before treatment and to investigate the association between neurocognitive and speech functioning. Prospective cohort study of newly diagnosed patients with HNC before treatment using a large sample obtained in a nationwide, multicenter setting (Netherlands Quality of Life and Biomedical Cohort Study in Head and Neck Cancer [NET-QUBIC] project). Objective neuropsychological measures of delayed recall, letter fluency, and executive functioning, as well as patient-reported outcome measures on neurocognitive speech and functioning, were collected before treatment. In total, 254 patients with HNC participated (71.7% male), with a mean (SD) age of 62 (10) years. The response rate ranged from 81.9% (208 of 254) to 84.6% (215 of 254). Objective neurocognitive measures indicated that 4.7% (10 of 212) to 15.0% (32 of 214) of patients were initially seen with moderate to severe cognitive impairment. Mild to moderate impairment was found in 12.3% (26 of 212) to 26.2% (56 of 214) of patients. The most altered domains were delayed recall and letter fluency. Seven percent (15 of 208) of the patients reported high levels of everyday neurocognitive failure, and 42.6% (89 of 209) reported speech problems. Objective neurocognitive function was not significantly associated with patient-reported neurocognitive or speech functioning, but the results from patient-reported outcome measures were significantly correlated. Results of this study demonstrate a high prevalence of impaired speech functioning among patients with HNC before treatment, which is in line with previous findings. A novel finding is that neurocognitive impairment is also highly prevalent as objectively measured and as self-perceived. Understanding the reason why patients with HNC are initially seen with neurocognitive impairment before the start of treatment is important because this impairment may complicate patient-clinician interaction and alter treatment adherence and because treatment itself may further worsen cognitive functioning. In addition, low self-perceived neurocognitive and speech functioning before treatment may decrease a patient's confidence in communicative participation and perceived quality of life. Disentangling the associations between objective and patient-reported neurocognitive and speech functions is an important area for future research.

Adaptive functioning in children with neurofibromatosis type 1: relationship to cognition, behavior, and magnetic resonance imaging.

To characterize the adaptive behavior profile of children with neurofibromatosis type 1 (NF1) and determine its relationship to neuropsychological functioning and non-neoplastic T2-weighted hyperintense brain lesions on brain magnetic resonance imaging (MRI). In this cross-sectional study, we retrospectively reviewed neuropsychological reports from 104 children with NF1 (56 males, 48 females; mean age 10y 4mo; standard deviation [SD] 3y 4mo; range 3y 5mo-17y 6mo), and extracted data from a range of cognitive and behavioral measures, including the Adaptive Behavior Assessment System (ABAS). Brain MRI was retrospectively reviewed in 42 individuals. Adaptive Behavior Assessment System scores were continuously distributed and pathologically shifted by 0.79 to 1.26SD across Conceptual, Social, and Practical domains, and 46.5% of individuals had a composite score in the borderline or impaired range. Impairment in adaptive functioning was correlated with deficits in executive function (r=-9.543, p<0.001), externalizing problems (r=-0.366, p<0.001), and attention (r=-9.467, p=0.001). Cluster analysis revealed three distinct phenotypic subgroups, one of which exhibited normal cognitive ability, but impaired adaptive functioning, with persistent deficits in executive function, behavioral problems, and attention-deficit/hyperactivity disorder symptomatology. There was no relationship between ABAS scores and the number or location of unidentified bright objects. Adaptive functioning deficits are common among children with NF1 and are associated with impairment in other cognitive/behavioral domains, independent of general cognitive ability. Deficits in adaptive behavior are common in children with neurofibromatosis type 1 (NF1). Poor adaptive functioning is associated with impairments in executive function, externalizing behaviors, and attention, regardless of cognitive ability. The presence or location of unidentified bright objects do not predict adaptive behavior skills in children with NF1.

A tale of two stories: Validity of an alternative story memory test in a sample of older adults

Objective: Many patients require repeat neuropsychological evaluations to determine change over time. Repeat evaluations lead to practice effects, which can impact the validity of the assessment. The current study assessed, in older adults, the validity of an alternative set of verbal memory stories created by Newcomer and colleagues.Method: A total 154 of non-demented adults, ages 60–92, completed the WMS-III logical memory (LM) stories and two Newcomer stories (Carson–Jones) as part of a larger battery of neurocognitive tests. The Carson–Jones stories were scored for: (1) verbatim (traditional) and (2) thematic (developed for this study) accuracy. Story memory variables were compared to each other and additional neurocognitive measures using bivariate correlations. A subset of participants (n = 133) completed magnetic resonance imaging (MRI) and various structural regions (e.g. thickness and volume of medial temporal lobe structures) were used to assess external validity of Carson–Jones stories with hierarchical multiple regression analyses.Results: There was a strong positive correlation between WMS-III LM and Carson–Jones stories for both verbatim and thematic scoring. Both scoring types showed convergent validity with other verbal memory measures (e.g. WMS-III LM and HVLT-R Delay/Learning) and divergent validity with Stroop Word Reading and JOLO. Regarding neuroimaging correlates, Carson–Jones verbatim scoring was significantly associated with left subiculum and left whole hippocampal volume whereas thematic scoring was significantly associated only with left subiculum.Conclusions: Newcomer stories appear to be a valid alternative to WMS-III LM stories in terms of assessing verbal memory in healthy older adults.

The Vitamins in Psychosis Study: A Randomized, Double-Blind, Placebo-Controlled Trial of the Effects of Vitamins B12, B6, and Folic Acid on Symptoms and Neurocognition in First-Episode Psychosis

BackgroundElevated homocysteine is observed in schizophrenia and associated with illness severity. The aim of this study was to determine whether vitamins B12, B6, and folic acid lower homocysteine and improve symptomatology and neurocognition in first-episode psychosis. Whether baseline homocysteine, genetic variation, sex, and diagnosis interact with B-vitamin treatment on outcomes was also examined. MethodsA randomized, double-blind, placebo-controlled trial was used. A total of 120 patients with first-episode psychosis were randomized to an adjunctive B-vitamin supplement (containing folic acid [5 mg], B12 [0.4 mg], and B6 [50 mg]) or placebo, taken once daily for 12 weeks. Coprimary outcomes were change in total symptomatology (Positive and Negative Syndrome Scale) and composite neurocognition. Secondary outcomes included additional measures of symptoms, neurocognition, functioning, tolerability, and safety. ResultsB-vitamin supplementation reduced homocysteine levels (p = .003, effect size = −0.65). B-vitamin supplementation had no significant effects on Positive and Negative Syndrome Scale total (p = .749) or composite neurocognition (p = .785). There were no significant group differences in secondary symptom domains. A significant group difference in the attention/vigilance domain (p = .024, effect size = 0.49) showed that the B-vitamin group remained stable and the placebo group declined in performance. In addition, 14% of the sample had elevated baseline homocysteine levels, which was associated with greater improvements in one measure of attention/vigilance following B-vitamin supplementation. Being female and having affective psychosis was associated with improved neurocognition in select domains following B-vitamin supplementation. Genetic variation did not influence B-vitamin treatment response. ConclusionsWhile 12-week B-vitamin supplementation might not improve overall psychopathology and global neurocognition, it may have specific neuroprotective properties in attention/vigilance, particularly in patients with elevated homocysteine levels, patients with affective psychosis, and female patients. Results support a personalized medicine approach to vitamin supplementation in first-episode psychosis.

Development and Preliminary Validation of a Virtual Reality–Based Measure of Response Inhibition Under Normal and Stressful Conditions

Response inhibition is a neurobehavioral construct important in understanding a range of various forms of psychopathology. Response inhibition is commonly assessed using paper-and-pencil behavioral measures and/or self-report questionnaires. Given that these assessment methods may be limited by a lack of ecological validity and retrospective recall biases, respectively, additional assessment methodologies are necessary. Virtual reality (VR) assessment may address some of the limitations of current assessment approaches in mental health. The purpose of this study was to therefore develop and preliminarily evaluate the validity of a VR-based measure of response inhibition and response inhibition under stress. Thirty-four participants completed the VR Task, as well as paper-and-pencil neurocognitive measures and self-report measures of attention and distress intolerance. Results suggest the VR Task performance converges with assessments of attention and response inhibition, and performance in the VR stressor condition is associated with perceived distress intolerance. These results, while highly preliminary, suggest that VR assessment of neurocognitive constructs relevant to mental health is feasible and a promising line of research.

PPAR and GST polymorphisms may predict changes in intellectual functioning in medulloblastoma survivors.

Advances in the treatment of pediatric medulloblastoma have led to improved survival rates, though treatment-related toxicity leaves children with significant long-term deficits. There is significant variability in the cognitive outcome of medulloblastoma survivors, and it has been suggested that this variability may be attributable to genetic factors. The aim of this study was to explore the contributions of single nucleotide polymorphisms (SNPs) in two genes, peroxisome proliferator activated receptor (PPAR) and glutathione-S-transferase (GST), to changes in general intellectual functioning in medulloblastoma survivors. Patients (n = 44, meanage = 6.71years, 61.3% males) were selected on the basis of available tissue samples and neurocognitive measures. Patients received surgical tumor resection, craniospinal radiation, radiation boost to the tumor site, and multiagent chemotherapy. Genotyping analyses were completed using the Illumina Human Omni2.5 BeadChip, and 41 single nucleotide polymorphisms (SNPs) were assessed across both genes. We used a machine learning algorithm to identify polymorphisms that were significantly associated with declines in general intellectual functioning following treatment for medulloblastoma. We identified age at diagnosis, radiation therapy, chemotherapy, and eight SNPs associated with PPARs as predictors of general intellectual functioning. Of the eight SNPs identified, PPARα (rs6008197), PPARγ (rs13306747), and PPARδ (rs3734254) were most significantly associated with long-term changes in general intellectual functioning in medulloblastoma survivors. PPAR polymorphisms may predict intellectual outcome changes in children treated for medulloblastoma. Importantly, emerging evidence suggests that PPAR agonists may provide an opportunity to minimize the effects of treatment-related cognitive sequelae in these children.

Exploring the use of the Hinting Task in first-episode psychosis

ABSTRACTIntroduction: The aim of the study was to elucidate the association between performance-related neurocognitive abilities and Theory of Mind (ToM) as measured by the Hinting Task (HT) performance and investigate the psychometric properties of the HT for use in First-Episode Psychosis (FEP).Methods: Cross-sectional data of 132 participants with FEP, aged 15–25 years, enrolled in a randomised controlled trial of vocational intervention, were analysed. A comprehensive cognitive battery including social cognitive and neurocognitive measures, a social and occupational functioning measure and psychopathological measures, were used. Psychometric properties were measured through bivariate correlations and associations with neurocognitive domains were assessed through hierarchical regression.Results: Low convergent validity of the HT with other ToM measures, moderate discriminant validity with an emotion recognition task, low predictive validity with social and occupational functioning, and high internal consistency were revealed. HT performance was significantly associated with verbal reasoning and verbal memory.Conclusion: Results provide preliminary evidence of low convergent validity and moderate discriminant validity of the HT in FEP, and the influence of verbal reasoning and verbal memory on HT performance, indicating that caution is warranted when employing the HT as a screening tool in isolation for detection of ToM deficits in FEP.

The Tower of London-DX 2nd Edition test: Preliminary norms for educationally disadvantaged Xhosa-speaking individuals

This study aimed to construct preliminary normative indications for educationally disadvantaged, Xhosa-speaking South African individuals on the Tower of London-Drexel University 2nd Edition test (TOL-DX 2nd Edition). The TOL-DX 2nd Edition is a commonly employed neurocognitive measure of executive function across seven indicators. The study sample included 39 Xhosa-speaking participants proficient in English, aged 19 to 40 years, with a Grade 11 or Grade 12 education attained at a poorly resourced school. Descriptive statistics in the form of means and standard deviations were used to describe the TOL-DX 2nd Edition scaled score normative indicators for the present sample. These preliminary norms were broadly equivalent to the United States standardisation for all seven test indexes. Larger studies with wider age, educational, and geographical distributions are suggested to generate norms that may be usable for clinical case interpretations among educationally disadvantaged South African individuals.

Brain connectivity tracks effects of chemotherapy separately from behavioral measures.

Several studies in cancer research have suggested that cognitive dysfunction following chemotherapy, referred to in lay terms as “chemobrain”, is a serious problem. At present, the changes in integrative brain function that underlie such dysfunction remain poorly understood. Recent developments in neuroimaging suggest that patterns of functional connectivity can provide a broadly applicable neuromarker of cognitive performance and other psychometric measures. The current study used multivariate analysis methods to identify patterns of disruption in resting state functional connectivity of the brain due to chemotherapy and the degree to which the disruptions can be linked to behavioral measures of distress and cognitive performance. Sixty two women (22 healthy control, 18 patients treated with adjuvant chemotherapy, and 22 treated without chemotherapy) were evaluated with neurocognitive measures followed by self-report questionnaires and open eyes resting-state fMRI scanning at three time points: diagnosis (M0, pre-adjuvant treatment), 1 month (M1), and 7 months (M7) after treatment. The results indicated deficits in cognitive health of breast cancer patients immediately after chemotherapy that improved over time. This psychological trajectory was paralleled by a disruption and later recovery of resting-state functional connectivity, mostly in the parietal and frontal brain regions. Mediation analysis showed that the functional connectivity alteration pattern is a separable treatment symptom from the decreased cognitive health. Current study indicates that more targeted support for patients should be developed to ameliorate these multi-faceted side effects of chemotherapy treatment on neural functioning and cognitive health.

The National Brain Injury Rescue and Rehabilitation Study - a multicenter observational study of hyperbaric oxygen for mild traumatic brain injury with post-concussive symptoms.

The National Brain Injury Rescue and Rehabilitation Project was established as a preliminary study to test the safety and practicality of multi-center hyperbaric oxygen administration for the post-concussive symptoms of chronic mild traumatic brain injury as a precursor to a pivotal, independent, multi-center, controlled clinical trial. This report presents the results for 32 subjects who completed a preliminary trial of hyperbaric oxygen several years before the passage of the 21st Century Cures Act. This study anticipated the Act and its reassessment of clinical research. Subjects received 40–82 one-hour treatments at 1.5 atmospheres absolute 100% oxygen. Outcome measures included repeated self-assessment measures and automated neurocognitive tests. The subjects demonstrated improvement in 21 of 25 neurocognitive test measures observed. The objective neurocognitive test components showed improvement in 13 of 17 measures. Earlier administration of hyperbaric oxygen post injury, younger age at the time of injury and hyperbaric oxygen administration, military status, and increased number of hyperbaric oxygen administrations were characteristics associated with improved outcomes. There were no adverse events. Hyperbaric oxygen was found to be safe, inexpensive and worthy of clinical application in the 21st Century model of facile data collection provided by recent research regulatory shifts in medicine. The study was approved by the ethics review committee of the Western Institutional Review Board (WIRB® Protocol #20090761).

Cultural Neuropsychology Considerations in the Diagnosis of HIV-Associated Neurocognitive Disorders.

Human Immunodeficiency Virus Type-I (HIV) is a health disparities issue that affects culturally and linguistically diverse (CALD) and underrepresented minority populations to a greater degree than non-Hispanic white populations. Neurologically speaking, CALD populations experience worse HIV-related health outcomes, which are exacerbated by inadequate neurocognitive measures, poor normative samples, and the complex interplay of sociocultural factors that may affect test interpretation. Although cross-cultural neuropsychologists are working diligently to correct this gap in the literature, currently, studies examining neurocognitive outcomes among CALD populations are sparse. The most well-studied CALD groups are of African American/Black and Latinx adults in the US, and the chapter therefore focuses on these studies. There is more limited work among other populations in the US, such as Asians, Native Hawaiians, Pacific Islanders, and American Indians/Alaskan Natives, and even fewer studies for many CALD populations outside of the US. For example, HIV neuropsychology data is rare or nonexistent in the First Peoples of Australia and Indigenous People of Canada. It is often not adequately reported in Europe for the migrant populations within those countries or other world regions that have historically large multicultural populations (e.g., South America, Caribbean countries, Asia, and Africa). Therefore, this chapter reviews HIV-related health disparities faced by CALD populations with focus on North American research where it has been specifically studied, with particular attention given to disparities in HIV-Associated Neurocognitive Disorders (HAND). International data was also included for research with focus on First Peoples of Australia and Indigenous People of Canada. The chapter also examines other sociocultural and health factors, including global and regional (e.g., rural versus urban) considerations, migration, and gender. Further, guidelines for incorporating sociocultural consideration into assessment and interpretation of neurocognitive data and HAND diagnosis when working with HIV-positive CALD populations that would be relevant internationally are provided.

Impulsivities and addictions: a multidimensional integrative framework informing assessment and interventions for substance use disorders.

Impulse control is becoming a critical survival skill for the twenty-first century. Impulsivity is implicated in virtually all externalizing behaviours and disorders, and figures prominently in the aetiology and long-term sequelae of substance use disorders (SUDs). Despite its robust clinical and predictive validity, the study of impulsivity is complicated by its multidimensional nature, characterized by a variety of trait-like personality dimensions, as well as by more state-dependent neurocognitive dimensions, with variable convergence across measures. This review provides a hierarchical framework for linking self-report and neurocognitive measures to latent constructs of impulsivity and, in turn, to different psychopathology vulnerabilities, including substance-specific addictions and comorbidities. Impulsivity dimensions are presented as novel behavioural targets for prevention and intervention. Novel treatment approaches addressing domains of impulsivity are reviewed and recommendations for future directions in research and clinical interventions for SUDs are offered. This article is part of the theme issue 'Risk taking and impulsive behaviour: fundamental discoveries, theoretical perspectives and clinical implications'.

Developmental changes in functional brain networks from birth through adolescence.

Investigation of the brain connectome using functional magnetic resonance imaging (fMRI) and measures derived from graph theory analysis has emerged as a new approach to study brain development, cognitive function, and neurophysiological disorders. Here we use graph theory analysis to examine the influence of age, sex, and neurocognitive measures on developmental changes to the global and regional topology of functional brain networks derived from fMRI data recorded in 189 healthy subjects from the age of 0-18 years during rest. We observed that Global Efficiency and Rich-Club coefficient increased with age and Local Efficiency and Small-Worldness decreased with age, while Modularity at the global level showed an inverted U-shaped trajectory during development. Marginally significant differences were observed in Local Efficiency, Small-Worldness, and Modularity at a global level between boys and girls throughout development. We also examine the effects of neurocognitive measures in boys and girls globally and locally. Our results provide new insight to understand brain maturation of functional brain connectome and its relation to cognitive development from birth through adolescence.

An Integrated Analysis of Neural Network Correlates of Categorical and Dimensional Models of Attention-Deficit/Hyperactivity Disorder

BackgroundAttention-deficit/hyperactivity disorder (ADHD) is a heterogeneous neurodevelopmental disorder, putatively induced by dissociable dysfunctional biobehavioral pathways. Here, we present a proof-of-concept study to parse ADHD-related heterogeneity in its underlying neurobiology by investigating functional connectivity across multiple brain networks to 1) disentangle categorical diagnosis-related effects from dimensional behavior-related effects and 2) functionally map these neural correlates to neurocognitive measures. MethodsWe identified functional connectivity abnormalities related to ADHD across 14 networks within a large resting-state functional magnetic resonance imaging dataset (n = 409; age = 17.5 ± 3.3 years). We tested these abnormalities for their association with the categorical ADHD diagnosis and with dimensional inattention and hyperactivity/impulsivity scores using a novel modeling framework, creating orthogonalized models. Next, we evaluated the relationship of these findings with neurocognitive measures (working memory, response inhibition, reaction time variability, reward sensitivity). ResultsWithin the default mode network, we mainly observed categorical ADHD-related functional connectivity abnormalities, unrelated to neurocognitive measures. Clusters within the visual networks primarily related to dimensional scores of inattention and reaction time variability, while findings within the sensorimotor networks were mainly linked to hyperactivity/impulsivity and both reward sensitivity and working memory. Findings within the cerebellum network and salience network related to both categorical and dimensional ADHD measures and were linked to response inhibition and reaction time variability. ConclusionsThis proof-of-concept study identified ADHD-related neural correlates across multiple functional networks, showing distinct categorical and dimensional mechanisms and their links to neurocognitive functioning.

Stress matters: Randomized controlled trial on the effect of probiotics on neurocognition

Probiotics are microorganisms that provide health benefits when consumed. In animals, probiotics reverse gut microbiome-related alterations in depression-like symptoms, in cognition, and in hormonal stress response. However, in humans, a causal understanding of the gut-brain link in emotion and cognition is lacking. Additionally, whether the effects of probiotics on neurocognition are visible only in presence of stress, remains unclear. We investigated the effects of a multispecies probiotic (Ecologic®Barrier) on specific neurocognitive measures of emotion reactivity, emotion regulation, and cognitive control using fMRI. Critically, we also tested whether probiotics can buffer against the detrimental effects of acute stress on working memory. In a double blind, randomized, placebo-controlled, between-subjects intervention study, 58 healthy participants were tested once before and once after a 28-day intervention.Without stress induction, probiotics did not affect brain, behavioral, or related self-report measures. However, relative to placebo, the probiotics group did show a significant stress-related increase in working memory performance after supplementation. This change was associated with intervention-related neural changes in frontal cortex during cognitive control exclusively in the probiotics group. Overall, our results show neurocognitive effects of a multispecies probiotic in healthy women only under challenging situations, buffering against the detrimental effects of stress on cognition.