Possible lingering effects of multiple past concussions

[Repeated mild traumatic brain injury in the parietal cortex inhibits expressions of NLG-1 and PSD-95 in the medulla oblongata of mice]

OBJECTIVE

To assess the effects of repeated mild traumatic brain injury (rmTBI) in the parietal cortex on neuronal morphology and synaptic plasticity in the medulla oblongata of mice.

METHODS

Thirty-two male ICR mice were randomly divided into sham operation group (n=8) and rmTBI group (n=24). The mice in the latter group were subjected to repeated mild impact injury of the parietal cortex by a free-falling object. The mice surviving the injuries were evaluated for neurological deficits using neurological severity scores (NSS), righting reflex test and forced swimming test, and pathological changes of the neuronal cells in the medulla oblongata were observed with HE and Nissl staining. Western blotting and immunofluorescence staining were used to detect the expressions of neuroligin 1(NLG-1) and postsynaptic density protein 95(PSD-95) in the medulla oblongata of the mice that either survived rmTBI or not.

RESULTS

None of the mice in the sham-operated group died, while the mortality rate was 41.67% in rmTBI group. The mice surviving rmTBI showed significantly reduced NSS, delayed recovery of righting reflex, increased immobility time in forced swimming test (P < 0.05), and loss of Nissl bodies; swelling and necrosis were observed in a large number of neurons in the medulla oblongata, where the expression levels of NLG-1 and PSD-95 were significantly downregulated (P < 0.05). The mice that did not survive rmTBI showed distorted and swelling nerve fibers and decreased density of neurons in the medulla oblongina with lowered expression levels of NLG-1 and PSD-95 compared with the mice surviving the injuries (P < 0.01).

CONCLUSION

The structural and functional anomalies of the synapses in the medulla oblongata may contribute to death and neurological impairment following rmTBI in mice.

Sports-Related Concussion Affects Cognitive Function in Adolescents: A Systematic Review and Meta-analysis

BACKGROUND

Rates of sports-related concussion (SRC) are high in adolescents. Ambiguity exists regarding the effect of SRC on cognitive function in adolescents.

PURPOSE

To rigorously examine adolescents' cognitive function after SRC.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

Web of Science, Scopus, and PubMed were searched from database inception until September 2021. Studies were included if participants were adolescents aged 13 to 18 years, if the definition of SRC was fully consistent with the Berlin Consensus Statement on Concussion in Sport, if the study included a control group or in-group baseline test, and if the study reported cognitive outcomes (eg, visual memory, processing speed) that could be separately extracted.

RESULTS

A total of 47 studies were included in the systematic review, of which 31 were included in the meta-analysis, representing 8877 adolescents with SRC. Compared with individuals in the non-SRC group, individuals with SRC had worse performance in cognitive function and reported more symptoms not only in the acute phase but also in the prolonged phase (1-6 months after injury) (visual memory: d = -0.21, 95% CI, -0.37 to -0.05, P = .012; executive function: d = -0.56, 95% CI, -1.07 to -0.06, P = .028; and symptoms: d = 1.17, 95% CI, 0.13 to 2.22, P = .028). Lower scores in most of the outcomes of cognitive function were observed at <3 days and at 3 to 7 days, but higher scores for verbal memory (d = 0.10; 95% CI, 0.03 to 0.17; P = .008) and processing speed (d = 0.17; 95% CI, 0.10 to 0.24; P < .001) were observed at 7 to 14 days after SRC relative to baseline. The effects of SRC on cognitive function decreased over time (100% of the variance in reaction time, P < .001; 99.94% of the variance in verbal memory, P < .001; 99.88% of the variance in visual memory, P < .001; 39.84% of the variance in symptoms, P = .042) in control group studies. Study design, participant sex, measurement tools, and concussion history were found to be modulators of the relationship between cognitive function and SRC.

CONCLUSION

This study revealed that adolescent cognitive function is impaired by SRC even 1 to 6 months after injury. Results of this study point to the need for tools to measure cognitive function with multiple parallel versions that have demographically diversiform norms in adolescents. Effective prevention of SRC, appropriate treatment, and adequate evaluation of cognitive function before return to play are needed in adolescent SRC management. Moreover, caution is warranted when using the baseline-to-postconcussion paradigm in return-to-play decisions.

Back from the sideline, but back to baseline? A pediatric case study examining neuropsychological functioning after sustaining multiple sport-related concussions

Most individuals recover quickly from a concussion; however, youth who sustain multiple concussions may be at risk for long-term cognitive impairments. This case study examines the neuropsychological performance of a 13-year-old malewith five head injuries. After his first concussion during study participation (fourth injury overall), several improvements were observed, likely due to practice effects, yet after sustaining another concussion <2 years later,declines were observed in visuoconstruction, verbal memory, and intellectual functioning. Across serial re-evaluation, his vocabulary knowledge declined, and fewer improvements were observed than anticipated when accounting for serial practice effects, highlighting the possible cumulative impact of multiple concussions.

Long-term effects of multiple concussions on prefrontal cortex oxygenation during repeated squat-stands in retired contact sport athletes

BACKGROUND

This study investigated the long-term effects of multiple concussions on prefrontal cortex oxygenation using near-infrared spectroscopy (NIRS) during a squat-stand maneuver that activated dynamic cerebral autoregulation.

METHODS

Active male retired contact sport athletes with a history of 3+ concussions (mTBI; n = 55), and active retired athletes with no concussion history (CTRL; n = 29) were recruited. Participants completed a 5-min squat-stand maneuve (10-s squat, 10-s stand, 0.05 Hz; 15 times). Oxygenated (O₂Hb), deoxygenated (HHb), total (tHb) hemoglobin, and hemoglobin difference (HbDiff) were analyzed through the change in maximal and minimal values during the test (∆MAX), Z-scores, and standard deviations.

RESULTS

mTBI group showed left prefrontal cortex O₂Hb ∆MAX (p = 0.046) and HbDiff ∆MAX (p = 0.018) were significantly higher. Within-group analyses showed significantly higher left HHb ∆MAX (p = 0.003) and lower left HbDiff Z-scores (p = 0.010) only in the mTBI group. The CTRL group demonstrated significantly lower left HbDiff SD (p = 0.039), tHb Z-scores (p = 0.030), and HbDiff ∆MAX (p = 0.037) compared to right prefrontal cortex response.

CONCLUSION

These preliminary results suggest changes in prefrontal cortex oxygenation potentially affecting the brain's ability to adapt to changing cerebral perfusion pressure after multiple previous concussions.

A Normative Reference vs. Baseline Testing Compromise for ImPACT: The CARE Consortium Multiple Variable Prediction (CARE-MVP) Norms

BACKGROUND

Sports medicine clinicians routinely use computerized neurocognitive testing in sport-related concussion management programs. Debates continue regarding the appropriateness of normative reference comparisons versus obtaining individual baseline assessments, particularly for populations with greater likelihood of having below- or above-average cognitive abilities. Improving normative reference methods could offer alternatives to perceived logistical and financial burdens imposed by universal baseline testing.

OBJECTIVES

To develop and validate the Concussion Assessment, Research, and Education (CARE) Consortium Multiple Variable Prediction (MVP) norms for the Immediate Postconcussion Assessment and Cognitive Testing (ImPACT).

METHODS

We developed the CARE-MVP norms for ImPACT composite scores using regression-based equations. Predictor variables included sex, race (white/Caucasian, black/African American, Asian, or Multiple Races), medical history [attention-deficit/hyperactivity disorder (ADHD), learning disorder (LD), prior concussion(s), prior psychiatric diagnosis], and an estimate of premorbid intellect (Wechsler Test of Adult Reading). CARE-MVP norms were first validated in an independent sample of healthy collegiate athletes by comparing predicted and actual baseline test scores using independent-samples t-tests and Cohen's d effect sizes. We then evaluated base rates of low scores in athletes self-reporting ADHD/LD (vs. non-ADHD/LD) and black/African American race (vs. white/Caucasian) across multiple normative reference methods (Chi square, Cramer's V effect size). Lastly, we validated the CARE-MVP norms in a concussed sample (dependent samples t test, Cohen's d effect size).

RESULTS

A total of 5233 collegiate athletes (18.8 ± 1.2 years, 70.5% white/Caucasian, 39.1% female) contributed to the CARE-MVP norms (development N = 2616; internal validation N = 2617). Race and WTAR score were the strongest and most consistent ImPACT score predictors. There were negligible mean differences between observed and predicted (CARE-MVP) baseline scores (Cohen's d < 0.1) for all ImPACT composite scores except Reaction Time (predicted ~ 20 ms faster than observed, d = - 0.28). Low score base rates were similar for athletes across subpopulations when using CARE-MVP norms (ADHD/LD, V = 0.017-0.028; black/African American, V = 0.043-0.053); while, other normative reference methods resulted in disproportionately higher rates of low scores (ADHD/LD, V = 0.062-0.101; black/African American race, V = 0.163-0.221). Acute (24-48 h) postconcussion ImPACT scores were significantly worse than CARE-MVP norms but notably varied as a function of concussion symptom severity.

CONCLUSIONS

Results support CARE-MVP norm use in populations typically underrepresented or not adjusted for in traditional normative reference samples, such as those self-reporting ADHD/LD or black/African American race. CARE-MVP norms improve upon prior normative methods and may offer a practical, simple alternative for collegiate institutions concerned about logistical and financial burden associated with baseline testing. An automated scoring program is provided.

Concussion in collegiate athletics: A link to academic achievement

Context

After concussion, many different symptoms can occur and persist that can affect daily functioning. Many of these symptoms could have implications in an athlete’s ability to return to academics. Unlike return to play, return to academics is less studied and less regulated. There is little research examining the effects of concussion on grade point average (GPA) and results have been inconsistent.

Objective

To examine the effects of concussion on college GPA.

Design

Retrospective observational study

Setting

University laboratory

Participants

Division I athletes after their first concussion (n = 26) and Division I athletes without a history of concussion (n = 30).

Main Outcome Measures

GPA and demographic information was obtained for the semester before injury, the semester of injury, and the semester after injury.

Results

Statistical analysis using generalized linear mixed model analysis revealed a significant interaction ( p < 0.05) of group (concussion vs. control) by time, with the concussed group having a significant decrease in GPA from semester before injury to semester of injury, and a significant main effect for sex ( p < 0.05) with females having higher GPAs than males.

Conclusions

Since the cognitive demands of academics can potentially exacerbate symptomology of concussion, the identification of students at risk for difficulties is critical.

Return to Sport Following Adolescent Concussion: Epidemiologic Findings From a High School Population

High school athletes sustaining a concussion require careful attention when determining return-to-sport (RTS) readiness. The purpose of this study was to determine epidemiological and RTS data of a large cohort of high school athletes who sustained 1 or more concussions. Records of 357 consecutive youth patients who sustained concussions and presented to a single health care system between September 2013 and December 2016 were reviewed. Demographic data, RTS, and concussion-related variables were obtained via chart review. Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) scores at baseline and following concussions were performed by neuropsychologists. The average age at injury was 15.5 years (range, 14-18 years), 61.9% of patients were male, 6.7% reported a loss of consciousness, and 14.3% reported amnesia, requiring 30.4±23.3 days of recovery prior to RTS. The most common sport of injury was football (27.7%). There was a high incidence of previous concussion (33.1%), and 32 athletes sustained a recurrent concussion. A multivariate model demonstrated that females, players with a history of concussion, and those diagnosed in-clinic rather than in-game required increased time to RTS. Memory ImPACT scores were found to increase as players had recurrent concussions. Visual motor speed and reaction time scores decreased with recurrent concussions. [Orthopedics. 2020;43(4):e306-e310.].

Functional magnetic resonance imaging study of working memory several years after pediatric concussion

PRIMARY OBJECTIVE

The neurophysiological effects of pediatric concussion several years after injury remain inadequately characterized. The objective of this study was to determine if a history of concussion was associated with BOLD response differences during an n-back working memory task in youth.

RESEARCH DESIGN

Observational, cross-sectional.

METHODS AND PROCEDURES

Participants include 52 children and adolescents (M = 15.1 years, 95%CI = 14.4-15.8, range = 9-19) with past concussion (n = 33) or orthopedic injury (OI; n = 19). Mean time since injury was 2.5 years (95%CI = 2.0-3.0). Measures included postconcussion symptom ratings, neuropsychological testing, and blood-oxygen-dependent-level (BOLD) functional magnetic resonance imaging (fMRI) during an n-back working memory task.

MAIN OUTCOMES AND RESULTS

Groups did not differ on accuracy or speed during the three n-back conditions. They also did not differ in BOLD signal change for the 1- vs. 0-back or 2- vs. 0-back contrasts (controlling for task performance).

CONCLUSIONS

This study does not support group differences in BOLD response during an n-back working memory task in youth who are on average 2.5 years post-concussion. The findings are encouraging from the perspective of understanding recovery after pediatric concussion.

Remote concussion history does not affect visually-guided reaching in young adult females

Aim:

We examined the long-term effects of concussions in young adult females on visuomotor behavior during a visually-guided reaching task of various complexities.

Materials & methods:

20 females with a history of longer than 6 months since a concussion and 20 healthy females quickly and accurately performed a delayed reach to a previously cued target.

Results:

As both cognitive and motor load increased, task performance decreased for both groups (p < 0.05). However, contrary to our primary hypothesis, no differences in task performance were found between the two experimental groups (p > 0.05).

Conclusion:

The young adult females with a remote history of concussion demonstrated no deficits in visuomotor behavior on an attention-mediated reaching task as compared with control participants.

Current literature is inconclusive regarding the long-term effects of concussion. Some have argued that the differing results are due to many uncontrolled factors in study design. In this study, 20 females with a history of concussion more than 6 months ago and 20 healthy females performed a reaching task under different levels of difficulty. As the reaching task got harder, both groups had greater difficulty doing the task quickly and accurately (p < 0.05). Surprisingly, however, no differences in reaching performance existed between the two groups (p > 0.05). Young adult females with a remote history of concussion demonstrated no greater problems with complicated reaching tasks when compared with control participants when experimental conditions are tightly controlled.

Utility of the Brain Injury Screening Index in Identifying Female Prisoners With a Traumatic Brain Injury and Associated Cognitive Impairment

There is a high prevalence of traumatic brain injury (TBI) in prisoners, but screening tools for identifying TBI in female prisoners are not readily available. Using a cross-sectional design, the psychometric properties of the Brain Injury Screening Index (BISI) were investigated in a closed United Kingdom female prison. Purposive sampling comprised 56 females. Assessment included clinical interview, the BISI, self-report measures of mood, and a battery of measures of cognitive functioning. Seven of the 10 clinical indicators on the BISI met test-retest reliability criteria. Two of the three BISI summary variables demonstrated correlations with questionnaires in the hypothesized directions; however, only two BISI variables were associated with cognitive functioning. Findings support further investigation into the validity and reliability of the BISI with a larger sample.

Mild Traumatic Brain Injury Burden Moderates the Relationship Between Cognitive Functioning and Suicidality in Iraq/Afghanistan-Era Veterans

OBJECTIVES

Suicidal ideation (SI) is highly prevalent in Iraq/Afghanistan-era veterans with a history of mild traumatic brain injury (mTBI), and multiple mTBIs impart even greater risk for poorer neuropsychological functioning and suicidality. However, little is known about the cognitive mechanisms that may confer increased risk of suicidality in this population. Thus, we examined relationships between neuropsychological functioning and suicidality and specifically whether lifetime mTBI burden would moderate relationships between cognitive functioning and suicidal ideation.

METHODS

Iraq/Afghanistan-era Veterans with a history of mTBI seeking outpatient services (N = 282) completed a clinical neuropsychological assessment and psychiatric and postconcussive symptom questionnaires.

RESULTS

Individuals who endorsed SI reported more severe post-traumatic stress disorder (PTSD), depression, and postconcussive symptoms and exhibited significantly worse memory performance compared to those who denied SI. Furthermore, mTBI burden interacted with both attention/processing speed and memory, such that poorer performance in these domains was associated with greater likelihood of SI in individuals with a history of three or more mTBIs. The pattern of results remained consistent when controlling for PTSD, depression, and postconcussive symptoms.

CONCLUSIONS

Slowed processing speed and/or memory difficulties may make it challenging to access and use past experiences to solve current problems and imagine future outcomes, leading to increases in hopelessness and SI in veterans with three or more mTBIs. Results have the potential to better inform treatment decisions for veterans with history of multiple mTBIs. (JINS, 2019, 25, 79-89).

Effects of concussions on visually guided motor actions: A literature review

Athletes must be able to successfully navigate the soccer pitch or hockey rink to win the game, requiring maximal cognitive resources to successfully compete. Concussions potentially deplete these resources, and the long-term impact of concussions on an individual's goal-directed visually guided behavior continues to elude the scientific community. While the acute effects on cognition and the motor system have been elucidated elsewhere, long-term effects on performance have been less clear. Additionally, most investigations into long-term postinjury motor behaviors have focused on balance and gait, with little focus on functional upper extremity movements. These arm movements require both cognitive and motor functions to successfully complete the task, such as visually guided reaching, and have received little attention. This review examines the current state of the literature to date on the long-term effects of concussions on cognitive and motor deficits affecting visuomotor behavior.

A Description and Evaluation of the Concussion Education Application HEADS UP Rocket Blades

BACKGROUND

Concussions are responsible for numerous emergency department visits and hospitalizations among children annually. However, there remains a great deal of confusion about how to prevent and manage concussions in youth. To teach children aged 6 to 8 years about concussion safety, the Centers for Disease Control and Prevention (CDC) created a mobile gaming application called HEADS UP Rocket Blades. This report introduces the game and presents findings on its evaluation.

METHODS

The aim of the game is to teach children what a concussion is, its commons signs and symptoms, how to prevent one, and what to do if one occurs. An early version of the game went through two rounds of usability testing with children and parents to obtain initial impressions and make improvements.

RESULTS

The first round of usability testing focused on the mechanics of the game. Based on feedback from this session, CDC and the developers simplified the messaging and adjusted the game's level of difficulty. The second round focused on the gaming experience. The children indicated that they enjoyed playing, and nearly all were able to relay at least one learning objective.

CONCLUSIONS

Parents and children rated Rocket Blades as a good learning tool and indicated that they would download it for personal use.

Population-based cohort study of the impacts of mild traumatic brain injury in adults four years post-injury

There is increasing evidence that some people can experience persistent symptoms for up to a year following mild TBI. However, few longitudinal studies of mild TBI exist and the longer-term impact remains unclear. The purpose of this study is to determine if there are long-term effects of mild traumatic brain injury (TBI) four-years later. Adults (aged ≥16 years) identified as part of a TBI incidence study who experienced a mild-TBI four-years ago (N = 232) were compared to age-sex matched controls (N = 232). Sociodemographic variables, prior TBI and symptoms were assessed at the time of injury. Four years post-injury participants completed the Rivermead Post-Concussion Symptom Questionnaire, Hospital Anxiety and Depression Scale, Pittsburgh Sleep Quality Index and the Participation Assessment with Recombined Tools. Analysis of covariance was used to compare differences between TBI cases four years post-injury and controls, controlling for prior TBI and depression. A multiple regression model was used to identify the predictors of increased symptoms and reduced participation. The mild-TBI sample experienced significantly increased self-reported cognitive symptoms (F = 19.90, p = <0.01) four years post-injury than controls. There were no differences between the groups for somatic (F = 0.02, p = 0.89) or emotional symptoms (F = 0.31, p = 0.58). Additionally, the mild-TBI group reported significantly poorer community participation across all three domains: productivity (F = 199.07, p = <0.00), social relations (F = 13.93, p = <0.00) and getting out and about (F = 364.69, p = <0.00) compared to controls. A regression model accounting for 41% of the variance in cognitive symptoms in TBI cases revealed a history of TBI, receiving acute medical attention and baseline cognitive symptoms, sleep quality, anxiety and depression were predictive of outcome. The results indicate that whilst somatic and emotional symptoms resolve over time, cognitive symptoms can become persistent and that mild TBI can impact longer-term community participation. Early intervention is needed to reduce the longer-term impact of cognitive symptoms and facilitate participation.

Epidemiology of recurrent traumatic brain injury in the general population: A systematic review

OBJECTIVE

To comprehensively assess recurrent traumatic brain injury (rTBI) risk and risk factors in the general population.

METHODS

We systematically searched MEDLINE, EMBASE, and the references of included studies until January 16, 2017, for general population observational studies reporting rTBI risk or risk factors. Estimates were not meta-analyzed due to significant methodologic heterogeneity between studies, which was evaluated using meta-regression.

RESULTS

Twenty-two studies reported recurrence risk and 11 reported on 27 potential risk factors. rTBI risk was heterogeneous and varied from 0.43% (95% confidence interval [CI] 0.19%-0.67%) to 41.92% (95% CI 34.43%-49.40%), with varying follow-up periods (3 days-55 years). Median time to recurrence ranged from 0.5 to 3.8 years. In studies where cases were ascertained from multiple points of care, at least 5.50% (95% CI 4.80%-6.30%) of patients experienced a recurrence after a 1-year follow-up. Studies that used administrative data/self-report surveys to ascertain cases tended to report higher risk. Risk factors measured at time of index traumatic brain injury (TBI) that were significantly associated with rTBI in more than one study were male sex, prior TBI before index case, moderate or severe TBI, and alcohol intoxication. Risk factors reported in a single study that were significantly associated with rTBI were epilepsy, not seeking medical care, and multiple factors indicative of low socioeconomic status.

CONCLUSIONS

rTBI is an important contributor to the general population TBI burden. Certain risk factors can help identify individuals at higher risk of these repeated injuries. However, higher quality research that improves on rTBI surveillance methodology is needed.

Talking with young children about concussions: an exploratory study

BACKGROUND

Concussion education for children early in their participation in organized sport may help shape lasting attitudes about concussion safety. However, existing programming and research focus on older ages.

METHODS

Qualitative interviews about concussions were conducted with twenty children between the ages of six and eight. Structural, descriptive and pattern coding were used to organize the transcribed interviews and identify emergent themes.

RESULTS

Eighteen of the participants indicated that they had heard of the word concussion, with 12 describing the injury as related to the brain or head. The most frequently described mechanisms of injury were impacts to the head or falls, and symptoms tended to be somatic, such as generalized pain. The most frequently endorsed strategy to avoid sustaining a concussion was to 'follow the rules.' Multiple participants referenced parents as an informal source of information about concussions.

CONCLUSIONS

While most participants demonstrated some awareness about concussions, there were clear knowledge gaps that can be addressed with developmentally appropriate concussion education programming. Consistent with their developmental stage, interventions targeted at children in this age range may be most successful if they use basic logic, concrete ideas, provide rules to be followed and engage parents in dissemination.

Cumulative Effects of Concussion History on Baseline Computerized Neurocognitive Test Scores: Systematic Review and Meta-analysis

Context:

It is unclear whether individuals with a history of single or multiple clinically recovered concussions exhibit worse cognitive performance on baseline testing compared with individuals with no concussion history.

Objective:

To analyze the effects of concussion history on baseline neurocognitive performance using a computerized neurocognitive test.

Data sources:

PubMed, CINAHL, and psycINFO were searched in November 2015. The search was supplemented by a hand search of references.

Study Selection:

Studies were included if participants completed the Immediate Post-concussion Assessment and Cognitive Test (ImPACT) at baseline (ie, preseason) and if performance was stratified by previous history of single or multiple concussions.

Study Design:

Systematic review and meta-analysis.

Level of Evidence:

Level 2.

Data Extraction:

Sample size, demographic characteristics of participants, as well as performance of participants on verbal memory, visual memory, visual-motor processing speed, and reaction time were extracted from each study.

Results:

A random-effects pooled meta-analysis revealed that, with the exception of worsened visual memory for those with 1 previous concussion (Hedges g = 0.10), no differences were observed between participants with 1 or multiple concussions compared with participants without previous concussions.

Conclusion:

With the exception of decreased visual memory based on history of 1 concussion, history of 1 or multiple concussions was not associated with worse baseline cognitive performance.

Increased Symptom Reporting in Young Athletes Based on History of Previous Concussions

Research documents increased symptoms in adolescents with a history of two or more concussions. This study examined baseline evaluations of 2,526 younger athletes, ages 10 to 14. Between-groups analyses examined Post Concussion Symptom Scale symptoms by concussion history group (None, One, Two+) and clusters of Physical, Cognitive, Emotional, and Sleep symptoms. Healthy younger athletes with a concussion history reported greater physical, emotional, and sleep-related symptoms than those with no history of concussion, with a greater endorsement in physical/sleep symptom clusters. Findings suggest younger athletes with a history of multiple concussions may experience residual symptoms.

A case matched study examining the reliability of using ImPACT to assess effects of multiple concussions

BACKGROUND

Approximately 3.8 million sport and recreational concussions occur per year, creating a need for accurate diagnosis and management of concussions. Researchers and clinicians are exploring the potential dose-response cumulative effects of concussive injuries using computerized neuropsychological exams, however, results have been mixed and/or contradictory. This study starts with a large adolescent population and applies strict inclusion criteria to examine how previous mild traumatic brain injuries affect symptom reports and neurocognitive performance on the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) computerized tool.

METHODS

After applying exclusion criteria and case matching, 204 male and 99 female participants remained. These participants were grouped according to sex and the number of previous self-reported concussions and examined for overall differences on symptoms reported and scores obtained on the ImPACT neurocognitive battery composites. In an effort to further reduce confounding factors due to the varying group sizes, participants were then case matched on age, sex, and body mass index and analyzed for differences on symptoms reported and scores obtained on the ImPACT neurocognitive battery composites.

RESULTS

Case matched analysis demonstrated males with concussions experience significantly higher rates of dizziness (p = .027, η² = .035), fogginess (p = .038, η² = .032), memory problems (p = .003, η² = .055), and concentration problems (p = .009, η² = .046) than males with no reported previous concussions. No significant effects were found for females, although females reporting two concussions demonstrated a slight trend for experiencing higher numbers of symptoms than females reporting no previous concussions.

CONCLUSIONS

The results suggest that male adolescent athletes reporting multiple concussions have lingering concussive symptoms well after the last concussive event; however, these symptoms were found to be conflicting and better explained by complainer versus complacent attitudes in the population examined. Our results conflict with a significant portion of the current literature that uses relatively lenient inclusion and exclusion criteria, providing evidence of the importance of strict inclusion and exclusion criteria and examination of confounding factors when assessing the effects of concussions.

Persistent problems 1 year after mild traumatic brain injury: a longitudinal population study in New Zealand

BACKGROUND

Mild traumatic brain injury (mTBI) is a common problem in general practice settings, yet previous research does not take into account those who do not attend hospital after injury. This is important as there is evidence that effects may be far from mild.

AIM

To determine whether people sustain any persistent effects 1 year after mTBI, and to identify the predictors of health outcomes.

DESIGN AND SETTING

A community-based, longitudinal population study of an mTBI incidence cohort (n = 341) from a mixed urban and rural region (Hamilton and Waikato Districts) of the North Island of New Zealand (NZ).

METHOD

Adults (>16 years) completed assessments of cognitive functioning, global functioning, post-concussion symptoms, mood, and quality of life over the year after injury.

RESULTS

Nearly half of participants (47.9%) reported experiencing four or more post-concussion symptoms 1 year post-injury. Additionally, 10.9% of participants revealed very low cognitive functioning. Levels of anxiety, depression, or reduced quality of life were comparable with the general population. Having at least one comorbidity, history of brain injury, living alone, non-white ethnic group, alcohol and medication use, and being female were significant predictors of poorer outcomes at 12 months.

CONCLUSION

Although some people make a spontaneous recovery after mTBI, nearly half continue to experience persistent symptoms linked to their injury. Monitoring of recovery from mTBI may be needed and interventions provided for those experiencing persistent difficulties. Demographic factors and medical history should be taken into account in treatment planning.

Concussion reporting, sex, and conformity to traditional gender norms in young adults

This study assessed whether between-sex differences in concussion reporting intention and behavior among young adults are explained by the extent to which the individual conforms to traditional masculine norms that often characterize contemporary sport culture. A survey of college athletes in the United States (n = 328) found greater symptom reporting intention among females as compared to males, but no difference in their likelihood continued play while experiencing symptoms of a possible concussion. Greater conformity to the norms of risk-taking was associated with greater likelihood of continued play while symptomatic among female athletes but not among male athletes. These findings suggest that gendered behavior, rather than biologically determined sex, is an important consideration for concussion safety in this age group. Addressing elements of the contemporary sport ethos that reinforce risk taking in service of athletic achievement may be a relevant direction for interventions aimed at improving injury reporting among all athletes.

Multiple Past Concussions in High School Football Players: Are There Differences in Cognitive Functioning and Symptom Reporting?

BACKGROUND

There is increasing concern about the possible long-term effects of multiple concussions, particularly on the developing adolescent brain. Whether the effect of multiple concussions is detectable in high school football players has not been well studied, although the public health implications are great in this population.

PURPOSE

To determine if there are measureable differences in cognitive functioning or symptom reporting in high school football players with a history of multiple concussions.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Participants included 5232 male adolescent football players (mean [±SD] age, 15.5 ± 1.2 years) who completed baseline testing between 2009 and 2014. On the basis of injury history, athletes were grouped into 0 (n = 4183), 1 (n = 733), 2 (n = 216), 3 (n = 67), or ≥4 (n = 33) prior concussions. Cognitive functioning was measured by the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery, and symptom ratings were obtained from the Post-Concussion Symptom Scale.

RESULTS

There were no statistically significant differences between groups (based on the number of reported concussions) regarding cognitive functioning. Athletes with ≥3 prior concussions reported more symptoms than did athletes with 0 or 1 prior injury. In multivariate analyses, concussion history was independently related to symptom reporting but less so than developmental problems (eg, attention or learning problems) or other health problems (eg, past treatment for psychiatric problems, headaches, or migraines).

CONCLUSION

In the largest study to date, high school football players with multiple past concussions performed the same on cognitive testing as those with no prior concussions. Concussion history was one of several factors that were independently related to symptom reporting.

Consistency of Self-Reported Concussion History in Adolescent Athletes

Relying on self-reported concussion injury history is common in both clinical care and research. However, young athletes may not provide consistent medical information. To date, little is known about the reliability of self-reported concussion history in high school students. This study examined whether student athletes reported their lifetime history of concussions consistently over time. Self-reported concussion history was examined in 4792 student athletes (ages 13-18) from Maine who completed a preseason health survey on two occasions (median re-test interval = 23.7 months; standard deviation = 7.3; interquartile range = 12.4-24.5). Consistency of self-reported concussion history was determined by differences in the number of concussions reported during the second survey. Inconsistent concussion history was defined primarily by a decrease in the number of lifetime concussions reported at the second testing, compared with at the first testing. The majority of the sample (80.3%) reported no change in the number of concussions between the two baseline assessments. A minority (15.9%; n = 763) reported more concussions during the second assessment. Only 3.8% (n = 181) of student athletes provided inconsistent concussion histories, defined as fewer concussions at the second assessment. Boys provided inconsistent concussion histories a little more frequently, compared with girls (5.3% and 2.0%, respectively; p < 0.001). Similarly, athletes with self-reported attention-deficit hyperactivity disorder (ADHD) provided inconsistent concussion histories somewhat more frequently, compared with those without ADHD (7.8% and 3.5%, respectively; p < 0.001). Of the athletes with inconsistent concussion histories, greater degree of inconsistency was associated with a greater number of concussions initially reported at baseline (r_s = 0.54; p < 0.001). Only a small proportion of student athletes provided inconsistent concussion histories. Male gender, ADHD, and greater number of baseline concussions were significantly associated with inconsistency in reporting. Overall, these findings suggest that student athletes are quite consistent when reporting their concussion history when surveyed twice during high school.

Concussion in the National Hockey League: a systematic review of the literature

Players in the National Hockey League (NHL) are often sidelined by injuries, including concussion. The acute, intermediate and long-term effects of repetitive head trauma remain a concern of many. In 1997, the NHL and NHL Players Association established the NHL-NHL Players Association Concussion Program to diagnose, assess and treat concussion via a standardized and scientific approach. Documenting and analyzing the trends, incidence and underlying mechanisms of concussion may help in devising future prevention and treatment plans for concussion in hockey in general and the NHL in particular. The purpose of this study, therefore, was to systematically review and summarize the existing published literature on the trends, incidence rates and underlying mechanisms of concussion in the NHL.

Imaging Correlates of Memory and Concussion History in Retired National Football League Athletes

IMPORTANCE

To our knowledge, this is the first study to show an association between concussion, cognition, and anatomical structural brain changes across the age spectrum in former National Football League athletes.

OBJECTIVE

To assess the relationship of hippocampal volume, memory performance, and the influence of concussion history in retired National Football League athletes with and without mild cognitive impairment (MCI).

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study assessed differences between groups, mean hippocampal volumes, and memory performance by computing age quintiles based on group-specific linear regression models corrected for multiple comparisons for both athletes and control participants. The study was conducted starting in November 2010 and is ongoing at a research center in the northern region of Texas. This current analysis was conducted from October 9, 2013, to August 21, 2014. Participants included 28 retired National Football League athletes, 8 of whom had MCI and a history of concussion, 21 cognitively healthy control participants, and 6 control participants with MCI without concussion.

MAIN OUTCOMES AND MEASURES

Hippocampal volume, age, California Verbal Learning Test scores, and the number of grade 3 (G3) concussions. In addition, the number of games played was examined as an objective variable pertaining to football history.

RESULTS

The mean (SD) age was 58.1 (13) years for the 28 former athletes and 59.0 (12) years for the 27 control participants. Retired athletes with concussion history but without cognitive impairment had normal but significantly lower California Verbal Learning Test scores compared with control participants (mean [SD], 52.5 [8] vs 60.24 [7]; P = .002); those with a concussion history and MCI performed worse (mean [SD], 37 [8.62]) compared with both control participants (P < .001) and athletes without memory impairment (P < .001). Among the athletes, 17 had a G3 concussion and 11 did not. Older retired athletes with at least 1 G3 concussion had significantly smaller bilateral hippocampal volumes compared with control participants at the 40th age percentile (left, P = .04; right, P = .03), 60th percentile (left, P = .009; right, P = .01), and 80th percentile (left, P = .001; right, P = .002) and a smaller right hippocampal volume compared with athletes without a G3 concussion at the 40th percentile (P = .03), 60th percentile (P = .02), and 80th percentile (P = .02). Athletes with a history of G3 concussion were more likely to have MCI (7 of 7) compared with retired athletes without a history of G3 concussion (1 of 5) older than 63 years (P = .01). In addition, the left hippocampal volume in retired athletes with MCI and concussion was significantly smaller compared with control participants with MCI (P = .03).

CONCLUSION AND RELEVANCE

Prior concussion that results in loss of consciousness is a risk factor for increased hippocampal atrophy and the development of MCI. In individuals with MCI, hippocampal volume loss appears greater among those with a history of concussion.

Engaging Teammates in the Promotion of Concussion Help Seeking

Concussion underreporting contributes to the substantial public health burden of concussions from sport. Teammates may be able to play an important role in encouraging injury identification and help seeking. This study assessed whether there was an association between beliefs about the consequences of continued play with a concussion and intentions to engage as a proactive bystander in facilitating or encouraging teammate help seeking for a possible concussion. Participants were 328 (male and female) members of 19 U.S. collegiate contact or collision sports teams. Athletes who believed that there were negative health or performance consequences of continued play with a concussion were significantly more likely than their peers to intend to encourage teammate help seeking, but not more likely to alert a coach or medical personnel. Additionally, athletes who believed that their teammates were more supportive of concussion safety were more likely to intend to engage as proactive bystanders in encouraging teammate help seeking. Exploring how to encourage bystander promotion of concussion safety is an important direction for future programming and evaluation research and may provide an opportunity to improve the effectiveness of concussion education.

Characterization of acute stress reaction following an IED blast-related mild traumatic brain injury

PRIMARY OBJECTIVE

To characterize an acute stress reaction (ASR) following an improvised explosive device (IED) blast-related mild traumatic brain injury (mTBI).

RESEARCH DESIGN

Participants were male, US military personnel treated in Afghanistan within 4 days following an IED-related mTBI event (n = 239).

METHODS AND PROCEDURES

Demographics, diagnosis of ASR, injury history and self-reported mTBIs, blast exposures and psychological health histories were recorded.

MAIN OUTCOMES AND RESULTS

In total, 12.5% of patients met ASR criteria. Patients with ASR were significantly younger and junior in rank (p < 0.05). Patients with ASR were more likely to experience the IED-blast while dismounted, report a loss of consciousness (LOC) and higher pain levels (p < 0.05). Adjusting for age and rank, multivariate logistic regression showed an association between mTBI history and ASR (AOR = 1.405; 95% CI = 1.105-1.786, p < 0.01). Adjusting for mechanism of injury (dismounted vs. mounted), LOC and pain, multivariate logistic regression showed an association between mTBI history and ASR (AOR = 1.453; 95% CI = 1.132-1.864, p < 0.01). Prior blast exposure and past psychological health issues were not associated with ASR.

CONCLUSIONS

A history of multiple mTBIs is associated with increased risk of ASR. Future research is warranted.

Baseline Neurocognitive Performance in Professional Lacrosse Athletes

Background:

Concussions have become a major public health concern for both youth and professional athletes. The long-term consequences of concussion can be debilitating or even life threatening. To reduce these concerns, baseline neurocognitive performance can aid decision making in postconcussion recovery and return to play for athletes sustaining concussions. To date, these data are not available for lacrosse athletes.

Purpose:

To present baseline neurocognitive performance for Major League Lacrosse (MLL) players and to determine differences between athletes with and without a history of concussion.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

A retrospective review was conducted of Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) scores from MLL players who completed baseline testing from June 2010 to June 2011. Inclusion required a valid baseline test and no history of concussion in the 3 months prior to testing. Means ± standard deviations were computed for all demographic variables and ImPACT composite scores including visual and verbal memory, reaction time, and visual motor processing speed. Independent-samples t tests were used to determine differences between athletes with and without a history of concussion.

Results:

Valid baseline ImPACT testing was available for 235 MLL athletes (mean age, 25.1 ± 3.0 years). Forty percent of MLL athletes (n = 94) reported a history of concussion, with 14% of those (n = 13) reporting a history of 3 or more previous concussions. There were no differences on any demographic variables between MLL athletes with and without a history of concussion. MLL athletes with a history of concussion had lower ImPACT composite scores than those without a history of concussion, although only the verbal memory composite was found to be statistically significant (MLL with concussion, 83.2 ± 10.8 vs MLL without concussion, 86.9 ± 9.5; P = .007).

Conclusion:

This study establishes baseline ImPACT scores for MLL and demonstrates that athletes with a history of concussion have poorer neurocognitive performance compared with MLL athletes without a history of concussion.

Clinical Relevance:

These data can serve as normative values for subsequent testing following concussion to assess neurocognitive recovery.

Multiple prior concussions are associated with symptoms in high school athletes

Objectives

The purpose of this study was to evaluate the association of prior concussion on baseline computerized neurocognitive testing in a large cohort of high school athletes.

Methods

This is a retrospective cohort study of student athletes from 49 Maine High Schools in 2010 who underwent baseline computerized neurocognitive evaluation with Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT®). As part of the ImPACT®, subjects reported a prior history of concussion as well as demographic information and a symptom questionnaire. We used linear regression to evaluate the association of prior concussion with baseline: (1) ImPACT® composite scores; and (2) symptom scores.

Results

Six thousand seventy-five subjects were included in the study, of whom 57% were boys. The majority of student athletes (85.3%) reported no prior history of concussion while 4.6% reported having sustained two or more prior concussions. On simple linear regression, increasing number of concussions was related to worse performance in verbal memory (P = 0.039) and greater symptoms scores (P < 0.001). On multivariate modeling, only the association with baseline symptoms remained (P < 0.001). Other factors associated with baseline symptom reporting in the multivariate model included mental health history, headache/migraine history, gender, developmental and/or learning problems, and number of prior concussions.

Interpretation

In this large-scale, retrospective survey study, history of multiple prior concussions was associated with higher symptom burden but not baseline computerized neurocognitive testing. The association between baseline symptom reporting and clinical and demographic factors was greater than the association with a history of multiple concussions.

Relationship between concussion history and neurocognitive test performance in National Football League draft picks

BACKGROUND

There are limited empirical data available regarding the relationship between concussion history and neurocognitive functioning in active National Football League (NFL) players in general and NFL draft picks in particular. Potential NFL draft picks undergo 2 neurocognitive tests at the National Invitational Camp (Scouting Combine) every year: the Wonderlic and, since 2011, the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT). After conclusion of the combine and before the draft, NFL teams invite potential draft picks to their headquarters for individual visits where further assessment may occur.

PURPOSE

To examine the relationship between concussion history and neurocognitive performance (ImPACT and Wonderlic) in a sample of elite NFL draft picks.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Over 7 years, 226 potential draft picks were invited to visit a specific NFL team's headquarters after the combine. The athletes were divided into 3 groups based on self-reported concussion history: no prior concussions, 1 prior concussion, and 2 or more prior concussions. Neurocognitive measures of interest included Wonderlic scores (provided by the NFL team) and ImPACT composite scores (administered either at the combine or during a visit to the team headquarters). The relationship between concussion history and neurocognitive scores was assessed, as were the relationships among the 2 neurocognitive tests.

RESULTS

Concussion history had no relationship to neurocognitive performance on either the Wonderlic or ImPACT.

CONCLUSION

Concussion history did not affect performance on either neurocognitive test, suggesting that for this cohort, a history of concussion may not have adverse effects on neurocognitive functioning as measured by these 2 tests. This study reveals no correlation between concussion history and neurocognitive test scores (ImPACT, Wonderlic) in soon-to-be active NFL athletes.

A narrative review of sports-related concussion and return-to-play testing with asymptomatic athletes

OBJECTIVE

The purpose of this literature review was to demonstrate, through examples in the current literature, the cumulative and long-term effects of multiple concussions, postinjury protocols, and the efficacy of current and past return-to-play guidelines.

METHODS

A PUBMED SEARCH WAS PERFORMED USING THE KEYWORDS AND KEY PHRASES: concussions and long-term effects, concussions and return to play, and multiple concussions. We limited the search to articles that had been published from August 2007 to August 2012 and were specific to human participants. Of the 450 total articles that the search returned, we selected studies specifically demonstrating athletes who were symptom-free, passed neuropsychological testing, returned to play, and were tested in measures of postural control, transcranial magnetic stimulation, electroencephalographic studies, and magnetic resonance imaging spectroscopy.

RESULTS

Selected studies show evidence that, although a previously concussed athlete may be symptom-free and returned to a neuropsychological baseline, the athlete may continue to have prolonged neurological abnormalities that could disqualify them from being ready to return to play.

CONCLUSION

It appears that some neurological deficits persist beyond the current return-to-play standards and that discrepancy exists between common practices of returning athletes to competition and new standards of published research.

Epidemiology of concussion in sport: a literature review

OBJECTIVE

The purpose of this study was to summarize sport concussion incidence data, identify sports that present higher injury frequency, reveal the degree of risk in some lesser-known sports, and outline specific details within the sports literature that raise additional concerns, such as helmet-to-helmet contact and player positions that experience frequent impact.

METHODS

A systematic literature review of Pub Med using keyword search on injury, concussion, and sports was performed through May 2012. Abstracts were identified, selections were made based upon inclusion criteria, and full-length articles were obtained. Additional articles were considered following review of reference sections. Articles were reviewed and tabulated according to sport.

RESULTS

Two hundred eighty-nine articles were screened, and 62 articles were reviewed. The overall incidence of concussion in sport ranged from 0.1 to 21.5 per 1000 athletic exposures. The lowest incidence was reported in swimming and diving. Concussion incidence was highest in Canadian junior ice hockey, but elevated incidence in American football remains a concern because of the large number of participants.

CONCLUSIONS

The literature reviewed included incidence of concussion on the field of play under real-world conditions and influenced by the current culture of sport. The studies examined in this article show that there is risk of concussion in nearly every sport. Some sports have higher concussion frequency than others, which may depend upon the forces and roles of the positions played in these sports. Younger athletes have a higher incidence of concussion, and female incidence is greater than male in many comparable sports. Headgear may reduce concussion in some sports but may also give athletes a false sense of protection.

Subjective, but not objective, lingering effects of multiple past concussions in adolescents

The existing literature on lingering effects from concussions in children and adolescents is limited and mixed, and there are no clear answers for patients, clinicians, researchers, or policy makers. The purpose of this study was to examine whether there are lingering effects of past concussions in adolescent athletes. Participants in this study included 643 competitive Bantam and Midget hockey players (most elite 20% by division of play) between 13 and 17 years of age (mean age=15.5, SD=1.2). Concussion history at baseline assessment was retrospectively documented using a pre-season questionnaire (PSQ), which was completed at home by parents and players in advance of baseline testing. Players with English as a second language, self-reported attention or learning disorders, a concussion within 6 months of baseline, or suspected invalid test profiles were excluded from these analyses. Demographically adjusted standard scores for the five composites/domains and raw symptom ratings from the brief Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) computerized battery were analyzed. Adolescent athletes with one or two or more prior concussions did not have significantly worse neurocognitive functioning on ImPACT than did those with no previous concussions. There were significantly more symptoms reported in those with two or more prior concussions than in those with no or one prior concussion. Adolescents with multiple previous concussions had higher levels of baseline symptoms, but there were not group differences in neurocognitive functioning using this brief computerized battery.

Sport-related concussion: "how many is too many?"

The long-term effects of multiple sport-related concussions are currently at the center of debate in the popular press and scientific community. The question, "How many concussions are too many," is frequently asked in the competitive sport environment by parents, athletes, and coaches. While research suggests that a history of concussion influences the risk and recovery from subsequent concussion, studies investigating the long-term effects of multiple concussions are less conclusive. This paper reviews the literature on multiple concussions and the potential long-term consequences of these injuries. Furthermore, this paper addresses how concussion history can inform clinical and return-to-play decisions. Recent studies incorporating novel brain imaging and electrophysiological technology for assessing residual impairment from multiple concussions are reviewed and the clinical implications of this work are discussed.