Baseline Neurocognitive Performance and Symptoms in Those With Attention Deficit Hyperactivity Disorders and History of Concussion With Previous Loss of Consciousness

Self-reported concussion history is not related to cortical volume in college athletes

The long-term consequences of concussion are still being uncovered but have been linked to disruptions in cognition and psychological well-being. Previous studies focusing on the association between concussion history and structural changes in the brain have reported inconsistent results. We sought to examine the effect of concussion history on cortical volume with a focus on functional networks. These networks are associated with many of the functions that can be disrupted in those with an extensive concussion history. We collected baseline behavioral data including the Immediate Post-Concussion Assessment and Cognitive Testing, a self-report measure of the number of diagnosed concussions, and structural MRI in college athletes (n=296; 263 men and 33 women, age range 17-24). Behavioral measures were collected by members of the Department of Athletics concussion management team using a standardized protocol as part of their on-boarding process. Collegiate athletes in the present study who self-reported concussion history did not report different baseline symptoms and did not exhibit consistent differences in cognitive performance relative to those who reported no concussion history. We found that concussion history was not related to cortical volume at the network or region level, even when we compared participants with two or more concussions to those with no concussion history. We did identify relationships between cortical volume in the visual network and dorsal attention network with cognitive performance. In addition to comparing cortical volume between individuals with and without reported concussion history, we also examined whether cortical volume changes could be observed within individuals from baseline to acutely following concussion. We found that network level cortical volume did not change within subjects from baseline measurement to acutely post-concussion. Together, these results suggest that both self-reported concussion history and acute concussion effects are not associated with changes in cortical volume in young adult athletes.

Effect of Sleep Duration and Concussion History on Neurocognitive Testing Symptoms for Post-injury States

OBJECTIVE

Evaluate the influence of sleep duration and concussion history on postconcussion symptoms in adolescent athletes.

DESIGN

Observational retrospective study using the Immediate Post-Concussion Assessment and Cognitive Testing and Post-Concussion Symptom Scale (PCSS). Multivariable linear regression assessed sleep hours against 22 PCSS symptoms, controlling for demographic and health variables.

SETTING

Urban concussion centers in Colorado and Florida, 2009 to 2019.

PARTICIPANTS

11 564 student-athletes aged 12 to 22, categorized by concussion history.

INTERVENTIONS

Analysis of sleep duration and concussion history in relation to neurocognitive and psychiatric symptom severity.

MAIN OUTCOME MEASURES

Primary outcomes included neurocognitive, psychiatric, and total symptom scores. Secondary outcomes were specific PCSS symptoms.

RESULTS

Among 5349 student-athletes, 2671 (49.9%) had no prior concussions and 2678 (50.1%) had 1 or more. For those without prior concussions, sleep was negatively associated with age (β = -0.18, 95% confidence interval [CI], -0.22 to -0.13, P < 0.0001), vomiting (β = -0.22, 95% CI, -0.38 to -0.05, P = 0.012), and difficulty concentrating (β = -0.11, 95% CI, -0.19 to -0.35, P = 0.005). In athletes with a history of concussion, less sleep correlated with decreased age (β = -0.11, 95% CI, -0.14 to -0.07, P < 0.0001), headache (β = -0.065, 95% CI, -0.12 to -0.01, P = 0.031), irritability (β = -0.08, 95% CI, -0.15 to -0.01, P = 0.021), and difficulty concentrating (β = -0.08, 95% CI, -0.15 to -0.01, P = 0.031) but increased sensitivity to light (β = 0.10, 95% CI, 0.001-0.137, P = 0.048), numbness/tingling (β = 0.15, 95% CI, 0.04-0.26, P = 0.008), and feeling slowed down (β = 0.13, 95% CI, 0.05-0.21, P = 0.001).

CONCLUSION

Sleep duration and concussion history are associated with variations in postconcussion symptom severity among adolescent athletes. This data underscore the need for individualized management strategies based on sleep patterns and concussion history.

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.

Baseline Evaluation of Concussion-Like Symptoms and Modifying Factors in Collegiate Club-Sport Athletes

CONTEXT

Collegiate club-sport athletes participate in a variety of competitive sports and have been understudied in the concussion literature. Baseline performance measures are warranted to better understand assessment and management.

OBJECTIVE

To quantify normative values and the effects of modifying factors sex, concussion history, diagnosed attention disabilities (attention-deficit/hyperactivity disorder [ADHD]), and sport type on baseline symptom evaluation among collegiate club-sport athletes.

DESIGN

Cross-sectional study.

SETTING

Retrospective chart review.

PATIENTS OR OTHER PARTICIPANTS

A total of 1034 collegiate club-sport athletes (N = 649 males, 62.7%) from 29 sports at a single institution.

MAIN OUTCOME MEASURE(S)

Chart reviews were conducted for club-sport athletes who completed athlete background and symptom information on the Sport Concussion Assessment Tool-5th edition as a baseline concussion assessment during a single academic year. Demographics (eg, age, sex, sport), background medical information (eg, concussion history, ADHD), and symptom evaluation, consisting of individual 22-item symptom reports, the total number of symptoms, symptom severity scores, and symptom factors (eg, physical, cognitive, insomnia, and emotional), were analyzed.

RESULTS

On baseline symptom reporting, 68% of club-sport athletes were asymptomatic, with mild symptoms described by 3% to 12% and moderate or severe symptoms by ≤4%. Modifier groups differed with a higher total number of symptoms and symptom severity in females (P < .001), individuals reporting a history of concussion (P < .001), and those with ADHD (total number P = .04, symptom severity P = .02). Similar significant findings were noted for females and the history of concussion group on all 4 symptom factors; however, those in collision or contact sports also indicated greater cognitive (P = .03) and insomnia (P = .02) factors. Those with ADHD endorsed more cognitive (P < .001) factors.

CONCLUSIONS

Normative symptoms for a collegiate club-sport sample revealed approximately 70% were asymptomatic. Higher total number of symptoms and symptom severity were demonstrated by females and those with a history of concussion. Cognitive-specific symptoms were greater in those diagnosed with ADHD and those who participated in collision or contact sports.

Neurodiversity in elite sport: a systematic scoping review

The objective of this systematic scoping review is to understand the extent and scope of evidence regarding neurodiversity in elite sport. This systematic scoping review considered epidemiological studies, com mentary and viewpoints papers, systematic review and meta-analyses, and any intervention or clinical treatment, management and practice studies in relation to neurodiversity in elite sport. Case studies and grey literature were ineligible for review. Neurodivergence included neurodevelopmental disorders such as autism spectrum disorder, attention-deficit hyperactivity disorder (ADHD) and specific learning disorders. Elite sport was defined as Olympic, Paralympic, national, international, professional and semiprofessional sport. The final 23 studies included in this review comprised 10 observational studies, 4 systematic/narrative reviews, 6 commentary/position statements and 3 qualitative studies. The literature reflected a major focus on ADHD as a risk factor for concussion and prognosis for postconcussion recovery. Further, there was a focus on the medical management of ADHD, regarding adherence to sporting antidoping regulations. One study focused on the experience of autism in athletes in elite sport settings through qualitative interviews. One study focused on anxiety disorders in elite athletes, with ADHD emerging as a major risk factor. There is a strong rationale for future research to build on the evidence for neurodiversity in elite sport to foster supportive and inclusive elite sporting environments.

Athletes With Attention-Deficit/Hyperactivity Disorder: Position Statement of the American Medical Society for Sports Medicine

ABSTRACT

Athletes of all ages may be affected by medical and mental health issues. Sports medicine physicians should be familiar with common conditions that may affect the well-being of athletes, such as attention-deficit/hyperactivity disorder (ADHD). ADHD behaviors have the potential to affect a person's ability to concentrate. It is likely that social and cognitive therapies combined with pharmacotherapy will be the most effective way to treat ADHD in athletes. Medications used for ADHD, especially stimulant types, are known to improve alertness, reaction time, anaerobic performance, and endurance, which would potentially improve athletic performance. Furthermore, stimulant medications may enable student athletes with ADHD to focus on academic studies for longer periods of time, beyond usual levels of fatigue, important for those who may be exhausted after practices and games. The purported performance enhancement effects and potential adverse effects of stimulant medications have prompted many sports governing bodies to ban prescription stimulants or establish strict rules for their use. Athletes taking physician-prescribed stimulants to treat ADHD need to provide the appropriate documentation for approval before competition or risk punitive measures. Physicians should strive to provide a high quality of care to athletes with ADHD through early diagnosis, appropriate and careful multidisciplinary treatment, and complete and timely documentation to facilitate continued sports participation.

Nicotine and the developing brain: Insights from preclinical models

Use of tobacco products during pregnancy is associated with increased risk for neurodevelopmental disorders in the offspring. Preclinical models of developmental nicotine exposure have offered valuable insights into the neurobiology of nicotine's effects on the developing brain and demonstrated lasting effects of developmental nicotine exposure on brain structure, neurotransmitter signaling and behavior. These models have facilitated discovery of novel compounds as candidate treatments for attention deficit hyperactivity disorder, a neurodevelopmental disorder associated with prenatal nicotine exposure. Using these models the significance of heritability of behavioral phenotypes from the nicotine-exposed pregnant female or adult male to multiple generations of descendants has been demonstrated. Finally, research using the preclinical models has demonstrated synergistic interactions between developmental nicotine exposure and repetitive mild traumatic brain injury that contribute to "worse" outcomes from the injury in individuals with attention deficit hyperactivity disorder associated with developmental nicotine exposure.

Repetitive Mild Traumatic Brain Injury in an Awake, Unanesthetized Mouse Model of Perinatal Nicotine Exposure Produces Transient Novelty-Seeking and Depression-Like Behaviors

Attention deficit hyperactivity disorder (ADHD) can be a risk factor for repetitive mild traumatic brain injury (mTBI) or concussions such as those that can occur in contact sports. Individuals with ADHD also appear to have a higher risk of poor neurocognitive outcomes after repetitive mTBI. Findings from clinical studies examining the interactions between ADHD and repetitive mTBI vary, likely because of variabilities in experimental design and outcome measures. We used a mouse model of perinatal nicotine exposure (PNE), which displays behavioral, neuroanatomical, and neurotransmitter features consistent with ADHD and subjected the mice to repetitive mTBI. We used a closed head model of mTBI in awake, unanesthetized mice to mimic concussions in humans. The mTBI was repeated three times daily for seven days. The mice in the PNE-mTBI group took longer to regain consciousness after the mTBI and showed transient novelty-seeking and depression-like behaviors. Before the repetitive mTBI, the mice in the PNE group showed attention deficit, which persisted after the mTBI. The mice in the control (non-PNE) group showed a transient attention deficit after the repetitive mTBI but not any of the other behavioral changes seen in the PNE-mTBI group. These findings from an unanesthetized mouse model with a pre-existing condition show that ADHD and repetitive mTBI together contribute to transient novelty-seeking and depression-like behavior supporting the notion that untreated ADHD may be a risk factor for poor neurocognitive outcomes after concussions.

Severity of Ongoing Post-Concussive Symptoms as a Predictor of Cognitive Performance Following a Pediatric Mild Traumatic Brain Injury

OBJECTIVE

This study aimed to examine the predictors of cognitive performance in patients with pediatric mild traumatic brain injury (pmTBI) and to determine whether group differences in cognitive performance on a computerized test battery could be observed between pmTBI patients and healthy controls (HC) in the sub-acute (SA) and the early chronic (EC) phases of injury.

METHOD

203 pmTBI patients recruited from emergency settings and 159 age- and sex-matched HC aged 8-18 rated their ongoing post-concussive symptoms (PCS) on the Post-Concussion Symptom Inventory and completed the Cogstate brief battery in the SA (1-11 days) phase of injury. A subset (156 pmTBI patients; 144 HC) completed testing in the EC (~4 months) phase.

RESULTS

Within the SA phase, a group difference was only observed for the visual learning task (One-Card Learning), with pmTBI patients being less accurate relative to HC. Follow-up analyses indicated higher ongoing PCS and higher 5P clinical risk scores were significant predictors of lower One-Card Learning accuracy within SA phase, while premorbid variables (estimates of intellectual functioning, parental education, and presence of learning disabilities or attention-deficit/hyperactivity disorder) were not.

CONCLUSIONS

The absence of group differences at EC phase is supportive of cognitive recovery by 4 months post-injury. While the severity of ongoing PCS and the 5P score were better overall predictors of cognitive performance on the Cogstate at SA relative to premorbid variables, the full regression model explained only 4.1% of the variance, highlighting the need for future work on predictors of cognitive outcomes.

Influence of Special Education, ADHD, Autism, and Learning Disorders on ImPACT Validity Scores in High School Athletes

OBJECTIVE

The Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) is commonly used to assist with post-concussion return-to-play decisions for athletes. Additional investigation is needed to determine whether embedded indicators used to determine the validity of scores are influenced by the presence of neurodevelopmental disorders (NDs).

METHOD

This study examined standard and novel ImPACT validity indicators in a large sample of high school athletes (n = 33,772) with or without self-reported ND.

RESULTS

Overall, 7.1% of athletes' baselines were judged invalid based on standard ImPACT validity criteria. When analyzed by group (healthy, ND), there were significantly more invalid ImPACT baselines for athletes with an ND diagnosis or special education history (between 9.7% and 54.3% for standard and novel embedded validity criteria) when compared to athletes without NDs. ND history was a significant predictor of invalid baseline performance above and beyond other demographic characteristics (i.e., age, sex, and sport), although it accounted for only a small percentage of variance. Multivariate base rates are presented stratified for age, sex, and ND.

CONCLUSIONS

These data provide evidence of higher than normal rates of invalid baselines in athletes who report ND (based on both the standard and novel embedded validity indicators). Although ND accounted for a small percentage of variance in the prediction of invalid performance, negative consequences (e.g., extended time out of sports) of incorrect decision-making should be considered for those with neurodevelopmental conditions. Also, reasons for the overall increase noted here, such as decreased motivation, "sandbagging", or disability-related cognitive deficit, require additional investigation.

Repetitive Mild Traumatic Brain Injury in a Perinatal Nicotine Exposure Mouse Model of Attention Deficit Hyperactivity Disorder

Attention deficit hyperactivity disorder (ADHD) increases the risk for concussion or mild traumatic brain injury (mTBI). At the same time, recommendations for the management of ADHD include participation in sports and other organized physical activities, including those that carry an increased risk of mTBI. Very little work has been done to determine the extent to which untreated ADHD adversely impacts behavioral outcomes of repeated mild concussions. Here, we used a perinatal nicotine exposure (PNE) mouse model of ADHD combined with a closed-head, repetitive mTBI model. The PNE mouse model carries significant construct, face, and predictive validity as a preclinical model of ADHD. Two-month-old PNE and control mice were subjected to closed-head repetitive mTBI or sham procedure once daily for 5 days. Object-based attention, novel object recognition memory, spatial working memory, and depression-like behavior were analyzed 1 day and 2 weeks following repeated mTBI. Consistent with our previous reports, mice in the PNE group showed significant deficits in object-based attention and working memory prior to mTBI. These deficits persisted following the repeated mTBI. Repeated mTBI produced a transient attention deficit in the control group but did not exacerbate the attention deficit that is characteristic of the PNE group. Although neither PNE nor repetitive mTBI alone influenced immobility in the tail suspension test, when PNE mice were subjected to mTBI, there was a transient increase in this measurement suggesting a synergistic effect of ADHD and mTBI on depression-like behavior. Thus, our data using the PNE mouse model suggest that ADHD may be a risk factor for transient depression following repeated mTBI and that repeated mTBI may be a risk factor for transient attention deficit.

Utility of a novel perceptual-motor control test for identification of sport-related concussion beyond current clinical assessments

Clinically feasible metrics, that can inform the concussion recovery decision making process by evaluating a unique domain beyond current testing domains (e.g., balance, neurocognition, symptoms, vestibular/ocular function) are still in need. The purpose of this study was to compare perceptual-motor control in adolescent athletes ≤21 days of sport-related concussion and healthy controls and evaluate the association of perceptual-motor control to the outcomes of commonly-used sport-related concussion clinical assessments. Athletes (age: 12-18 years) with sport-related concussion (n = 48) and healthy controls (n = 24) completed the Perception-Action Coupling Task (PACT), whose outcomes are mean reaction, movement, initiation, response time, and accuracy. ImPACT outcomes are verbal/visual memory scores, motor processing speed, and reaction time. Vestibular-Ocular Motor Screen (VOMS) outcomes are symptoms from: smooth pursuit, horizontal/vertical saccades, near-point of convergence, horizontal/vestibular ocular-reflex, and visual motion sensitivity. CONCUSSED demonstrated ~5% deficit in overall perceptual-motor accuracy during PACT compared to CONTROLS (p = 0.03). PACT accuracy negatively correlated with smooth pursuits(r = -0.29), and horizontal (r = -0.35)/vertical (r = -0.30) saccades. The C5.0 decision tree determined PACT accuracy was the most relevant predictor of sport-related concussion when no visual motion sensitivity symptoms were reported and Visual Memory was >66. Perceptual-motor control tests may complement current sport-related concussion assessments when neurocognition and vestibular/ocular motor system are not grossly impaired.

Investigating the Range of Symptom Endorsement at Initiation of a Graduated Return-to-Play Protocol After Concussion and Duration of the Protocol: A Study From the National Collegiate Athletic Association-Department of Defense Concussion, Assessment, Research, and Education (CARE) Consortium

BACKGROUND

Organizations recommend that athletes should be asymptomatic or symptom-limited before initiating a graduated return-to-play (GRTP) protocol after sports-related concussion, although asymptomatic or symptom-limited is not well-defined.

HYPOTHESES

(1) There will be a range (ie, beyond zero as indicator of "symptom-free") in symptom severity endorsement when athletes are deemed ready to initiate a GRTP protocol. (2) Baseline symptom severity scores and demographic/preinjury medical history factors influence symptom severity scores at the commencement of the GRTP protocol. (3) Greater symptom severity scores at GRTP protocol initiation will result in longer protocol duration. (4) Symptom severity scores will not differ between those who did and did not sustain a repeat injury within 90 days of their initial injury.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Across 30 universities, athletes (N = 1531) completed assessments at baseline and before beginning the GRTP protocol, as determined by local medical staff. Symptom severity scores were recorded with the symptom checklist of the Sport Concussion Assessment Tool-3rd Edition. Nonparametric comparisons were used to examine the effect of medical, demographic, and injury factors on symptom endorsement at GRTP protocol initiation, as well as differences in symptom severity scores between those who did and did not sustain a repeat injury within 90 days. A Cox regression was used to examine the association between symptom severity scores at GRTP protocol initiation and protocol duration.

RESULTS

Symptom severity scores at the time when the GRTP protocol was initiated were as follows: 0 to 5 (n = 1378; 90.0%), 6 to 10 (n = 76; 5.0%), 11 to 20 (n = 42; 3.0%), and ≥21 (n = 35; 2.0%). Demographic (sex and age), medical (psychiatric disorders, attention-deficit/hyperactivity disorder, learning disorder), and other factors (baseline symptom endorsement and sleep) were significantly associated with higher symptom severity scores at the GRTP initiation (P < .05). The 4 GRTP initiation time point symptom severity score groups did not significantly differ in total time to unrestricted RTP, χ²(3) = 1.4; P = .73. When days until the initiation of the GRTP protocol was included as a covariate, symptom severity scores between 11 and 20 (P = .02; hazard ratio = 1.44; 95% CI, 1.06-1.96) and ≥21 (P < .001; hazard ratio = 1.88; 95% CI, 1.34-2.63) were significantly associated with a longer GRTP protocol duration as compared with symptom severity scores between 0 and 5. Symptom severity scores at GRTP initiation did not significantly differ between those who sustained a repeat injury within 90 days and those who did not (U = 29,893.5; P = .75).

CONCLUSION

A range of symptom severity endorsement was observed at GRTP protocol initiation, with higher endorsement among those with higher baseline symptom endorsement and select demographic and medical history factors. Findings suggest that initiation of a GRTP protocol before an absolute absence of all symptoms is not associated with longer progression of the GRTP protocol, although symptom severity scores >10 were associated with longer duration of a GRTP protocol. Results can be utilized to guide clinicians toward optimal GRTP initiation (ie, balancing active recovery with avoidance of premature return to activity).