Network Structure of Physical, Cognitive, and Emotional Symptoms at Preseason Baseline in Student Athletes with Attention-Deficit/ Hyperactivity Disorder

Patterns and predictors of concussion symptom presentations in NCAA athletes

Sport-related concussion (SRC) is a complex injury, and SRCs are notably prevalent among National Collegiate Athletic Association (NCAA) athletes. We analysed SRCs and associated exposure data collected within the NCAA Injury Surveillance Program during 2014-2019. A total of 1,709 SRCs were reported with complete symptom profiles during the study period (Women's sports n = 499; Men's sports n = 1,210). Event type and academic class year most commonly predicted specific symptom presentations among athletes in men's sports, while symptom presentation among athletes in women's sports was most commonly predicted by class year and sport classification. We observed 78 and 69 significant pairwise symptom dependencies in men's and women's sports athletes, respectively; odds of longer symptom resolution time were higher with greater counts of symptoms with strongest cross-domain associations. Our findings highlight several contextual predictors of specific symptom presentations and identify parsimonious symptom subsets that may indicate protracted recovery among men's and women's sports athletes.

Preclinical Models of Attention Deficit Hyperactivity Disorder: Neurobiology, Drug Discovery, and Beyond

OBJECTIVE

We offer an overview of ADHD research using mouse models of nicotine exposure.

METHOD

Nicotine exposure of C57BL/6 or Swiss Webster mice occurred during prenatal period only or during the prenatal and the pre-weaning periods. Behavioral, neuroanatomical and neurotransmitter assays were used to investigate neurobiological mechanisms of ADHD and discover candidate ADHD medications.

RESULTS

Our studies show that norbinaltorphimine, a selective kappa opioid receptor antagonist is a candidate novel non-stimulant ADHD treatment and that a combination of methylphenidate and naltrexone has abuse deterrent potential with therapeutic benefits for ADHD. Other studies showed transgenerational transmission of ADHD-associated behavioral traits and demonstrated that interactions between untreated ADHD and repeated mild traumatic brain injury produced behavioral traits not associated with either condition alone.

CONCLUSION

Preclinical models contribute to novel insights into ADHD neurobiology and are valuable tools for drug discovery and translation to benefit humans with ADHD.

Network analysis and relationship of symptom factors to functional outcomes and quality of life following mild traumatic brain injury: a TRACK-TBI study

Introduction

Mild traumatic brain injury (mTBI) is a heterogenous injury which can be difficult to characterize and manage. Using cross-sectional network analysis (NA) to conceptualize mTBI symptoms offers an innovative solution to identify how mTBI symptoms relate to each other. The centrality hypothesis of network theory posits that certain symptoms in a network are more relevant (central) or have above average influence over the rest of the network. However, no studies have used NA to characterize the interrelationships between symptoms in a cohort of patients who presented with mTBI to a U.S. Level 1 trauma center emergency department and how subacute central symptoms relate to long-term outcomes.

Methods

Patients with mTBI (Glasgow Coma Scale = 13-15) evaluated across 18 U.S. Level 1 trauma centers from 2013 to 2019 completed the Rivermead Post-Concussion Symptoms Questionnaire (RPQ) at 2 weeks (W2) post-injury (n = 1,593) and at 3 months (M3), 6 months (M6), and 12 months (M12) post-injury. Network maps were developed from RPQ subscale scores at each timepoint. RPQ scores at W2 were associated with M6 and M12 functional and quality of life outcomes.

Results

Network structure did not differ across timepoints, indicating no difference in symptoms/factors influence on the overall symptom network across time. The cognitive factor had the highest expected influence at W2 (1.761), M3 (1.245), and M6 (1.349). Fatigue had the highest expected influence at M12 (1.275). The emotional factor was the only other node with expected influence >1 at any timepoint, indicating disproportionate influence of emotional symptoms on overall symptom burden (M3 = 1.011; M6 = 1.076).

Discussion

Several symptom factors at 2-weeks post-injury were more strongly associated with incomplete recovery and/or poorer injury-related quality of life at 6 and 12 months post-injury than previously validated demographic and clinical covariates. The network analysis suggests that emotional, cognitive, and fatigue symptoms may be useful treatment targets in this population due to high centrality and activating potential of the overall symptom network.

Associations among the workplace violence, burnout, depressive symptoms, suicidality, and turnover intention in training physicians: a network analysis of nationwide survey

Depression and anxiety are the most common mental disorders among physicians, who have a greater risk of suicide than those in other professional occupations. Relationships among a demanding workload, workplace violence, burnout, and intention to turnover have also been reported. The current study examined the principal components and propagating patterns of mental health and working environment interactions in training physicians. A total of 1981 training physicians completed online self-report questionnaires during September-October (midpoint of the training year) 2020. Regularized partial correlations in a mixed graphical model (MGM) and joint probability distributions (directed acyclic graph; DAG) were estimated for four subtypes of workplace violence (verbal abuse/physical violence perpetrated by clients/hospital staff), three burnout subdomains (Maslach Burnout Inventory), thoughts about quitting, and nine depressive symptoms, including suicidality, comprising the DSM-5 diagnostic criteria for major depressive disorder (assessed using the Patient Health Questionnaire-9). Thoughts of death/self-harm showed directional dependencies on the joint probability distributions of psychomotor agitation/retardation, concentration difficulty, self-reproach, and sadness in the DAG. In the MGM, a partial correlation with psychomotor agitation/retardation (r = 0.196) accounted for 56.5% of the variance in thoughts of death/self-harm. Partial correlations with concentration difficulties (r = 0.294), self-reproach (r = 0.257), changes in appetite (r = 0.184), and worker-on-worker physical violence (r = 0.240) in the MGM accounted for 54.4% of the variance in psychomotor agitation/retardation. Thoughts about quitting were partially correlated with and dependent upon the joint probability distributions of emotional exhaustion (r = 0.222), fatigue (r = 0.142), anhedonia (r = 0.178), and sadness (r = 0.237). In contrast, worker-on-worker (r = 0.417) and client-on-physician (r = 0.167) verbal abuse had regularized partial correlations with directional dependencies on thoughts about quitting. Organization-level interventions aiming to reduce the worker-on-worker violence and individual-level approaches of clinical screening program and psychiatric counseling clinic are required. Follow-up studies to verify the effectiveness of these interventions for training physicians are needed.

Multidomain concussion symptoms in adolescents: A network analysis

Concussion is a heterogeneous injury involving symptoms and impairment that represent multiple domains (e.g., anxiety, cognitive, vestibular). Network analysis, a modeling technique that estimates relationships among symptoms, provides a statistically sound and clinically practical method for evaluating these interrelationships. The purpose of this study was to examine, using network analysis, relationships among clinical assessments and multidomain symptom report within a sample of adolescent patients following a concussion. Participants included 326 patients (49.7% female) aged 10-21 years presenting to a concussion specialty clinic within 28 days of a diagnosed concussion. Participants completed the Post-Concussion Symptom Scale (PCSS) and Vestibular-Ocular Motor Screening (VOMS) tool at initial visit. Network models were applied to PCSS symptoms initially, and then applied to VOMS and PCSS symptom data together. Dizziness (Expected influence (EI) = 1.10) and sadness (EI = 1.91) were most central (i.e., highest cumulative partial correlations) to the symptom network. Numerous interdomain relationships were supported, including irritability with mental fogginess (edgeweight = 0.12), dizziness with headache (edgeweight = 0.16), and dizziness with vision problems (edgeweight = 0.13). Community analyses resulted in VOMS groupings by domain (e.g., vestibular) and symptom (e.g., dizziness). The findings suggest a more direct focus on symptom interrelationships, such as how dizziness contributes to emotional symptoms, may help guide and better target treatments. Also, results suggest grouping VOMS assessment by symptom (e.g., dizziness) and item (e.g., vestibular-ocular reflex) may better reflect underlying impairments reflected by these symptom-item combinations.

Network analysis applied to post-concussion symptoms in two mild traumatic brain injury samples

Objective

A latent disease explanation cannot exclusively explain post-concussion symptoms after mild traumatic brain injury (mTBI). Network analysis offers an alternative form of explanation for relationships between symptoms. The study aimed to apply network analysis to post-concussion symptoms in two different mTBI cohorts; an acute treatment-seeking sample and a sample 10 years post-mTBI.

Method

The treatment-seeking sample (n = 258) were on average 6 weeks post-injury; the 10 year post mTBI sample (n = 193) was derived from a population-based incidence and outcomes study (BIONIC). Network analysis was completed on post-concussion symptoms measured using the Rivermead Post-Concussion Questionnaire.

Results

In the treatment-seeking sample, frustration, blurred vision, and concentration difficulties were central to the network. These symptoms remained central in the 10 year post mTBI sample. A Network Comparison Test revealed evidence of a difference in network structure across the two samples (p = 0.045). However, the only symptoms that showed significant differences in strength centrality across samples were irritability and restlessness.

Conclusion

The current findings suggest that frustration, blurred vision and concentration difficulties may have an influential role in the experience and maintenance of post-concussion symptoms. The impact of these symptoms may remain stable over time. Targeting and prioritising the management of these symptoms may be beneficial for mTBI rehabilitation.

Characterizing the Network Structure of Post-Concussion Symptoms

OBJECTIVE

Assessment of post-concussion symptoms is implemented at secondary, post-secondary, and professional levels of athletics. Network theory suggests that disorders can be viewed as a set of interacting symptoms that amplify, reinforce, and maintain one another. Examining the network structure of post-concussion symptoms may provide new insights into symptom comorbidity and may inform targeted treatment. We used network analysis to examine the topology of post-concussion symptoms using the Post-Concussion Symptom Scale (PCSS) in high school athletes with recent suspected sport-related concussion.

METHOD

Using a cross-sectional design, the network was estimated from Post Concussion Symptom Scale scores from 3,292 high school athletes, where nodes represented symptoms and edges represented the association between symptoms. Node centrality was calculated to determine the relative importance of each symptom in the network.

RESULTS

The network consisted of edges within and across symptom domains. "Difficulty concentrating" and "dizziness" were the most central symptoms in the network. Although not highly central in the network, headaches were the highest rated symptom.

CONCLUSIONS

The interconnectedness among symptoms supports the notion that post-concussion symptoms are interrelated and mutually reinforcing. Given their central role in the network, "difficulty concentrating" and "dizziness" are expected to affect the activation and persistence of other post-concussion symptoms. Interventions targeting difficulties with concentration and dizziness may help alleviate other symptoms. Our findings could inform the development of targeted treatment with the aim of reducing overall symptom burden. Future research should examine the trajectory of post-concussion symptom networks to advance the clinical understanding of post-concussive recovery.

Changes in ImPACT Cognitive Subtest Networks Following Sport-Related Concussion

OBJECTIVE

High school athletes are administered ImPACT at the start of the academic year or sport season and again after suspected concussion. Concussion management involves the comparison of baseline and post-injury cognitive scores with declines in scores providing evidence for concussive injury. A network framework may provide additional information about post-concussive cognitive changes and expand characterization of sport-related concussion (SRC) recovery.

DESIGN

Retrospective cohort study.

SETTING

High school.

PARTICIPANTS

High school athletes (n = 1553) were administered ImPACT at baseline (T1), post-SRC (T2 = 72 h of injury), and prior to return to play (T3 = within two weeks post-injury).

INDEPENDENT VARIABLES

ImPACT cognitive subtest scores.

MAIN OUTCOME MEASURES

Cognitive networks were calculated and compared over three time points. Centrality indices were calculated to determine the relative importance of cognitive variables within networks.

RESULTS

Network connectivity increased from T1 to T2 and remained hyperconnected at T3. There was evidence of network reorganization between T1 and T3. Processing speed was central within each network, and visual memory and impulsivity became more central over time.

CONCLUSIONS

The results suggest potential evidence of cognitive network change over time. Centrality findings suggest research specific to visual memory and impulse control difficulties during the post-concussion recovery period is warranted. Network analysis may provide additional information about cognitive recovery following SRC and could potentially serve as an effective means of monitoring persisting cognitive symptoms after concussion.

The Post-Concussion Symptom Scale: Normative Data for Adolescent Student-Athletes Stratified by Gender and Preexisting Conditions

BACKGROUND

The Post-Concussion Symptom Scale (PCSS) is a self-report questionnaire measuring symptoms that commonly occur after a concussion; however, these symptoms are nonspecific and can be related to co-occurring orthopaedic injuries (eg, cervical strain) or patient characteristics and preexisting conditions, even in the absence of a recent injury. As such, clinicians may have difficulty determining whether symptom elevations are attributable to a recent concussion as opposed to a confounding injury or a preexisting condition, which may be especially difficult when preinjury baseline symptom data are unavailable.

PURPOSE

This study aimed to further validate the 4-factor model of the PCSS (ie, cognitive, sleep-arousal, physical, and affective symptoms) with adolescent student-athletes and provide normative reference data for each factor and the total score, stratified by gender and preexisting health conditions.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Participants were 9358 adolescent student-athletes who completed the PCSS during a preseason baseline evaluation (mean age, 14.9 years; SD, 1.3 years [range, 13-18 years]; 49.3% boys). The 4-factor model of the PCSS was tested for the full sample and separately for boys and girls using confirmatory factor analysis. Symptom severity percentiles were created for the PCSS total score and each factor, stratified by gender and preexisting conditions (ie, attention-deficit/hyperactivity disorder, mental health history, headache/migraine history, learning disability/dyslexia, academic problems, and concussion history).

RESULTS

The 4-factor model of the PCSS replicated in the full sample (comparative fit index [CFI] = 0.959) and in both gender groups (boys: CFI = 0.961; girls: CFI = 0.960). The total PCSS score at the 84th percentile varied by preexisting conditions as follows: healthy participants = 8, attention-deficit/hyperactivity disorder = 18, mental health history = 26, headache/migraine history = 18, learning disability = 19, and academic problems = 17. On all PCSS subscales, participants with a mental health history had the highest scores, and high scores were associated with having >1 preexisting condition. Girls had higher scores than boys for each stratification.

CONCLUSION

The 4-factor model of the PCSS replicates for adolescent student-athletes. Gender, number of preexisting conditions, and mental health history are important factors to account for when interpreting PCSS symptom severity. The normative data provided herein could assist clinicians in determining whether an adolescent student-athlete is presenting with persistent postconcussion symptoms or a typical symptom experience based on their gender and personal health history.

Investigating the structure of trait rumination in autistic adults: A network analysis

LAY ABSTRACT

Autistic adults are substantially more likely to develop depression than individuals in the general population, and recent research has indicated that certain differences in thinking styles associated with autism may play a role in this association. Rumination, the act of thinking about the same thing over and over without a functional outcome, is a significant risk factor for depression in both autistic and non-autistic adults. However, little is known about how different kinds of rumination relate to each other and to depressive symptoms in the autistic population specifically. To fill this gap in knowledge, we recruited a large online sample of autistic adults, who completed questionnaire measures of both the tendency to ruminate and symptoms of depression. By examining the interacting network of rumination and depression symptoms, this study was able to identify particular aspects of rumination-such as thinking repetitively about one's guilty feelings or criticizing oneself-that may be particularly important in maintaining these harmful thought patterns in autistic adults. Although further study is needed, it is possible that the symptoms identified as most "influential" in the network may be particularly good targets for future interventions for mood and anxiety disorders in the autistic population.

The structure of post-concussion symptoms in adolescent student athletes: confirmatory factor analysis and measurement invariance

Objective: This study examined factor models for the Post-Concussion Symptom Scale (PCSS) at baseline and after suspected sport-related concussion, and measurement invariance from pre-injury to post-injury assessments and across age, gender, and health history groups (e.g., attention-deficit/hyperactivity disorder, psychiatric history). Methods: Adolescent student athletes (ages 13-18) completed a baseline PCSS (n = 39,015; 54.3% boys) and a subsample within 21 days of a suspected concussion (n = 1,554; 56.7% boys) completed a post-injury PCSS. Five models were evaluated for fit and invariance. Results: Confirmatory factor analyses showed good baseline and post-injury model fit for a previously supported four-factor model (i.e., cognitive-sensory, sleep-arousal, vestibular-somatic, and affective), an alternative four-factor model (i.e., cognitive, sleep-arousal, physical, and affective), and an incomplete bifactor model with vestibular-somatic and affective specific factors, along with partial invariance from pre-injury to post-injury assessments. Partial-to-full invariance was established for each model at baseline across demographic and health history groups. Conclusions: Results showed empirical and conceptual support for both PCSS subscales (i.e., cognitive, sleep-arousal, physical, and affective) and a total score for use in pre-injury to post-injury assessments and across demographic and health history groups at baseline. Future normative data, stratified by demographics and health history, could provide more precise symptom assessments for concussion management.