Cerebral concussion in athletes: evaluation and neuropsychological testing

Top-100 Most-Cited Sports-Related Concussion Articles Focus on Symptomatology, Epidemiology, and Demographics

Purpose

To analyze the top-100 cited articles on sports-related concussions together with a bibliometric analysis to determine citations by year, level of evidence, study design, and several other factors related to the top referenced articles in sports concussions.

Methods

The Clarivate Analytics Web of Knowledge database was used to gather data using Boolean queries to capture all possible iterations of sports-related concussion research. Articles were organized in descending order based on the number of citations and included or excluded based on relevance to concussion. Collected information included author name, publication year, country of origin, journal name, article type, study focus, and the level of evidence.

Results

The top-100 articles were cited 31,197 times with an average of 312.0 citations per publication. More than one half were published in 2006 or later (52). Cohort studies and descriptive articles were the most prevalent study types (22 each). Studies with Level V evidence were the most common (33). The most common areas of study were symptomatology (short term, long term) with 17 articles, followed by epidemiology/demographics with 16 articles. The least common area of study was concussion prevention (2 articles), followed by management/treatment, diagnostics (labs, imaging) with 4 articles each.

Conclusions

We identified the most influential studies in sports-related concussion based on number of citations and citation density. A majority of these articles were published in the United States after 2006 and are most commonly cohort studies (Level IV evidence) and descriptive articles (Level V evidence). Current research focuses most heavily on the symptomatology and epidemiology/demographics of sports concussion.

Clinical Relevance

This study serves to identify the most influential articles in sports-related concussion and identify research topics with general deficiencies within the field of sports-related concussion research.

Do male and female adolescents report symptoms differently after concussion?

We investigated sex-based differences in the presence and severity of aggregated symptom indicators as well as individual concussion symptoms.Materials and Methods: A cross-sectional examination of sex differences in symptoms reported by adolescents upon initial concussion evaluation at a concussion clinic. Nine hundred and eighty-six adolescents completed the Sport Concussion Assessment Tool (SCAT5) symptom checklist. Chi-square and Mann-Whitney U tests were used for differences in the presence and severity of symptoms, respectively. Sex differences in global indices of symptom distress were compared.Results: Females endorsed more symptoms (Female: Median (M)=15, Interquartile range (IQR):9-18 vs. Male: M=11, IQR: 6-15, p<0.001) and a greater total symptom score (Female: M=37, IQR:16-45 vs. Male: M=20, IQR:8-39). After False Discovery Rate (FDR) adjustment, females endorsed the presence of 21 of 22 individual symptoms more frequently than males (p≤ 0.039), with greater symptom severity for 20 of 22 individual symptoms (p≤0.036). Moderate ESs were observed for sex-based differences in the total symptom score and the global severity index. Small ESs was observed for differences in most individual symptoms.Conclusions: The greater frequency and severity of concussion symptoms reported by female adolescents highlights the importance of considering sex as a modifier for the management of concussion.

Can Neurocognitive Function Predict Lower Extremity Injuries in Male Collegiate Athletes?

The purpose of this study is to demonstrate whether neurocognitive evaluation can confirm the association between neurocognitive level and postural control and to analyze the relationship between neurocognitive level and acute musculoskeletal injury in male non-net sports athletes. Seventy-seven male non-net sports athletes participated in this study. The Standardized Assessment of Concussion (SAC), Landing Error Scoring System (LESS), Balance Error Scoring System (BESS), and Star Excursion Balance Test (SEBT) were used for testing; we collected data related to injury history for six months after testing. Pearson's correlation analysis, logistic regression, and the independent sample t-test were used for statistical analysis. The correlation between SAC and SEBT results was weak to moderate (p < 0.05). Eleven of the seventy-seven participants experienced acute lower limb injuries. SAC, LESS, BESS, and SEBT results have no effect on the occurrence of acute lower extremity injuries (p > 0.05) and were not statistically different between the injured and non-injured groups (p > 0.05). Therefore, using the SAC score alone to determine the risk factor of lower extremity injuries, except in the use of assessment after a concussion, should be cautioned against.

Digital neuropsychological assessment: Feasibility and applicability in patients with acquired brain injury

INTRODUCTION

Digital neuropsychological assessment (d-NPA) has several advantages over paper-and-pencil tests in neuropsychological assessment, such as a more standardized stimulus presentation and response acquisition. We investigated (1) the feasibility and user-experience of a d-NPA in patients with acquired brain injury (ABI) and healthy controls; (2) the applicability of conventional paper-and-pencil norms on digital tests; and (3) whether familiarity with a tablet would affect test performance on a tablet.

METHOD

We administered a d-NPA in stroke patients (n = 59), traumatic brain injury patients (n = 61) and healthy controls (n = 159). The neuropsychological tests were presented on a tablet and participants used a pencil stylus to respond. We examined the completion rate to assess the feasibility, and a semi-structured interview was conducted to examine the user-experience. The applicability of conventional norms was examined by the number of healthy controls performing <10^th percentile, which was expected to be no more than 10%. The effect of tablet familiarity on test performance was examined with a regression-based model.

RESULTS

Overall, 94% of patients completed the d-NPA. The d-NPA was considered pleasant by patients and healthy controls. Conventional norms that exist for paper-and-pencil tests were not applicable on the digital version of the tests, as up to 34% of healthy controls showed an abnormal performance on half of the tests. Tablet familiarity did not affect test performance on a tablet, indicating that participants who were more experienced with working with a tablet did not perform better on digital tests.

CONCLUSIONS

The administration of a d-NPA is feasible in patients with ABI. Familiarity with a tablet did not impact test performance, which is particularly important in neuropsychological assessment. Future research should focus on developing norms in order to implement a d-NPA in clinical practice.

A Decade of mTBI Experience: What Have We Learned? A Summary of Proceedings From a NATO Lecture Series on Military mTBI

Mild traumatic brain injury (mTBI, also known as a concussion) as a consequence of battlefield blast exposure or blunt force trauma has been of increasing concern to militaries during recent conflicts. This concern is due to the frequency of exposure to improvised explosive devices for forces engaged in operations both in Iraq and Afghanistan coupled with the recognition that mTBI may go unreported or undetected. Blasts can lead to mTBI through a variety of mechanisms. Debate continues as to whether exposure to a primary blast wave alone is sufficient to create brain injury in humans, and if so, exactly how this occurs with an intact skull. Resources dedicated to research in this area have also varied substantially among contributing NATO countries. Most of the research has been conducted in the US, focused on addressing uncertainties in management practices. Development of objective diagnostic tests should be a top priority to facilitate both diagnosis and prognosis, thereby improving management. It is expected that blast exposure and blunt force trauma to the head will continue to be a potential source of injury during future conflicts. An improved understanding of the effects of blast exposure will better enable military medical providers to manage mTBI cases and develop optimal protective measures. Without the immediate pressures that come with a high operational tempo, the time is right to look back at lessons learned, make full use of available data, and modify mitigation strategies with both available evidence and new evidence as it comes to light. Toward that end, leveraging our cooperation with the civilian medical community is critical because the military experience over the past 10 years has led to a renewed interest in many similar issues pertaining to mTBI in the civilian world. Such cross-fertilization of knowledge will undoubtedly benefit all. This paper highlights similarities and differences in approach to mTBI patient care in NATO and partner countries and provides a summary of and lessons learned from a NATO lecture series on the topic of mTBI, demonstrating utility of having patients present their experiences to a medical audience, linking practical clinical care to policy approaches.

Executive Dysfunction after a Sport-Related Concussion Is Independent of Task-Based Symptom Burden

A sport-related concussion (SRC) results in short- and long-term deficits in oculomotor control; however, it is unclear whether this change reflects executive dysfunction and/or a performance decrement caused by an increase in task-based symptom burden. Here, individuals with a SRC - and age- and sex-matched controls - completed an antisaccade task (i.e., saccade mirror-symmetrical to a target) during the early (initial assessment ≤12 days) and later (follow-up assessment <30 days) stages of recovery. Antisaccades were used because they require top-down executive control and exhibit performance decrements following an SRC. Reaction time (RT) and directional errors were included with pupillometry, because pupil size in the antisaccade task has been shown to provide a neural proxy for executive control. In addition, the Sport-Concussion Assessment Tool (SCAT-5) symptom checklist was completed prior to and after each oculomotor assessment to identify a possible task-based increase in symptomology. The SRC group yielded longer initial assessment RTs, more directional errors, and larger task-evoked pupil dilations (TEPD) than the control group. At the follow-up assessment, RTs for the SRC and control group did not reliably differ; however, the former demonstrated more directional errors and larger TEPDs. SCAT-5 symptom severity scores did not vary from the pre- to post-oculomotor evaluation for either initial or follow-up assessments. Accordingly, an SRC imparts a persistent executive dysfunction to oculomotor planning independent of a task-based increase in symptom burden. These findings evince that antisaccades serve as an effective tool to identify subtle executive deficits during the early and later stages of SRC recovery.

Traumatic brain injury increases plasma astrocyte-derived exosome levels of neurotoxic complement proteins

Possible involvement of complement (C) systems in the pathogenesis of traumatic brain injury (TBI) was investigated by quantifying Cproteins in plasma astrocyte-derived exosomes (ADEs) of subjects with sports-related TBI (sTBI) and TBI in military veterans (mtTBI) without cognitive impairment. All sTBI subjects (n = 24) had mild injuries, whereas eight of the mtTBI subjects had moderate, and 17 had mild injuries. Plasma levels of ADEs were decreased after acute sTBI and returned to normal within months. Cprotein levels in ADEs were from 12- to 35-fold higher than the corresponding levels in neuron-derived exosomes. CD81 exosome marker-normalized ADE levels of classical pathway C4b, alternative pathway factor D and Bb, lectin pathway mannose-binding lectin (MBL), and shared neurotoxic effectors C3b and C5b-9 terminal C complex were significantly higher and those of C regulatory proteins CR1 and CD59 were lower in the first week of acute sTBI (n = 12) than in controls (n = 12). Most C abnormalities were no longer detected in chronic sTBI at 3-12 months after acute sTBI, except for elevated levels of factor D, Bb, and MBL. In contrast, significant elevations of ADE levels of C4b, factor D, Bb, MBL, C3b and C5b-9 terminal C complex, and depressions of CR1 and CD59 relative to those of controls were observed after 1-4 years in early chronic mtTBI (n = 10) and persisted for decades except for normalization of Bb, MBL, and CD59 in late chronic mtTBI (n = 15). Complement inhibitors may be useful therapeutically in acute TBI and post-concussion syndrome.

Altered levels of plasma neuron-derived exosomes and their cargo proteins characterize acute and chronic mild traumatic brain injury

Neuron-derived exosomes (NDEs) were enriched by anti-L1CAM antibody immunoabsorption from plasmas of subjects ages 18-26 yr within 1 wk after a sports-related mild traumatic brain injury (acute mTBI) ( n = 18), 3 mo or longer after the last of 2-4 mTBIs (chronic mTBI) ( n = 14) and with no recent history of TBI (controls) ( n = 21). Plasma concentrations of NDEs, assessed by counts and levels of extracted exosome marker CD81, were significantly depressed by a mean of 45% in acute mTBI ( P < 0.0001), but not chronic mTBI, compared with controls. Mean CD81-normalized NDE levels of a range of functional brain proteins were significantly abnormal relative to those of controls in acute but not chronic mTBI, including ras-related small GTPase 10, 73% decrease; annexin VII, 8.8-fold increase; ubiquitin C-terminal hydrolase L1, 2.5-fold increase; AII spectrin fragments, 1.9-fold increase; claudin-5, 2.7-fold increase; sodium-potassium-chloride cotransporter-1, 2.8-fold increase; aquaporin 4, 8.9-fold increase (3.6-fold increase in chronic mTBI); and synaptogyrin-3, 3.1-fold increase (1.3-fold increase in chronic mTBI) (all acute mTBI proteins P < 0.0001). In chronic mTBI, there were elevated CD81-normalized NDE levels of usually pathologic β-amyloid peptide 1-42 (1.6-fold, P < 0.0001), P-T181-tau (2.2-fold, P < 0.0001), P-S396-tau (1.6-fold, P < 0.01), IL-6 (16-fold, P < 0.0001), and prion cellular protein (PRPc) (5.1-fold, P < 0.0001) with lesser or greater (IL-6, PRPc) increases in acute mTBI. Increases in NDE levels of most neurofunctional proteins in acute, but not chronic, mTBI, and elevations of most NDE neuropathological proteins in chronic and acute mTBI delineated phase-specificity. Longitudinal studies of more mTBI subjects may identify biomarkers predictive of and etiologically involved in mTBI-induced neurodegeneration.-Goetzl, E. J., Elahi, F. M., Mustapic, M., Kapogiannis, D., Pryhoda, M., Gilmore, A., Gorgens, K. A., Davidson, B., Granholm, A.-C., Ledreux, A. Altered levels of plasma neuron-derived exosomes and their cargo proteins characterize acute and chronic mild traumatic brain injury.

Mild traumatic brain injury induces memory deficits with alteration of gene expression profile

Repeated mild traumatic brain injury (rmTBI), the most common type of traumatic brain injuries, can result in neurological dysfunction and cognitive deficits. However, the molecular mechanisms and the long-term consequence of rmTBI remain elusive. In this study, we developed a modified rmTBI mouse model and found that rmTBI-induced transient neurological deficits and persistent impairments of spatial memory function. Furthermore, rmTBI mice had long-lasting detrimental effect on cognitive function, exhibiting memory deficits even 12 weeks after rmTBI. Microarray analysis of whole genome gene expression showed that rmTBI significantly altered the expression level of 87 genes which are involved in apoptosis, stress response, metabolism, and synaptic plasticity. The results indicate the potential mechanism underlying rmTBI-induced acute neurological deficits and its chronic effect on memory impairments. This study suggests that long-term monitoring and interventions for rmTBI individuals are essential for memory function recovery and reducing the risk of developing neurodegenerative diseases.

A Comparative Meta-Analysis of the Effects of Concussion on a Computerized Neurocognitive Test and Self-Reported Symptoms

CONTEXT

  Meta-analyses examining construct-specific cognitive impairment concurrently with self-reported symptoms postconcussion are sparse.

OBJECTIVE

  To review the literature on the effects of concussion on construct-specific neurocognitive declines and to compare them with self-reported symptoms before 1 week and between 1 and 3 weeks postconcussion.

DATA SOURCES

  Relevant studies in PubMed, CINAHL, and PsycINFO published from January 1, 1999 through November 30, 2015.

STUDY SELECTION

  Studies were included if participants completed the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) before and after concussion and if test performance and Postconcussion Symptom Scale (PCSS) scores were reported at both times.

DATA EXTRACTION

  After reviewing the full texts, we extracted data from 17 studies consisting of 29 independent samples; therefore, this meta-analysis consisted of 1777 unique participants.

DATA SYNTHESIS

  The Hedges g effect size (ES) was estimated. A random-effects or fixed-effects model was used based on heterogeneity findings. When heterogeneity was present, we used meta-regression to assess unexplained between-studies variance. Within the first week of injury, the ESs were small to moderate for cognitive declines, ranging from -0.43 (95% confidence interval [CI] = -0.52, -0.35) to -0.67 (95% CI = -0.77, -0.58), and large for the PCSS score (Hedges g = -0.81; 95% CI = -0.91, -0.71). After 1 week, the ESs for cognitive declines (Hedges g range = -0.25 [95% CI = -0.35, -0.15] to -0.37 [95% CI = -0.55, -0.19]) and PCSS score (Hedges g = -0.38; 95% CI = -0.53, -0.22) were also small. Within 2 weeks of injury, PCSS score and time since injury weakly moderated the cognitive ES.

CONCLUSIONS

  When a neurocognitive test was administered within 1 week of injury, the ES was larger for self-reported symptoms than for ImPACT scores generated at the same session. After 1 week of injury, the ESs for ImPACT and PCSS scores were comparable. If the athlete reports symptoms within 1 week of injury, administering a cognitive test does not appear to offer additional information to the clinician. However, if the athlete does not report symptoms postconcussion, cognitive testing may inform the clinical management of the injury.

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.

Validity of the Immediate Post Concussion Assessment and Cognitive Testing (ImPACT)

BACKGROUND

The immediate post concussion assessment and cognitive testing (ImPACT) is the most widely used concussion assessment tool. Despite its popularity, it is unclear if validation studies for the ImPACT test covered all aspects of validity to support its widespread use in research and clinical practice.

OBJECTIVE

The purpose of this report is to review literature surrounding the validity and the utility of the ImPACT test.

DATA SOURCES AND APPRAISAL

A systematic review of relevant studies in PubMed, CINAHL, and PsycINFO was carried out. Studies were evaluated using the STROBE (strengthening the reporting of observational studies in epidemiology) or the STARD (standards for reporting of diagnostic accuracy) criteria.

RESULTS

The literature search yielded 5968 studies. Sixty-nine studies met the inclusion criteria and were included in the qualitative review. Although the convergent validity of ImPACT was supported, evidence of discriminant and predictive validity, diagnostic accuracy and responsiveness was inconclusive. The utility of the ImPACT test after acute symptom resolution was sparse. The review found many factors influenced the validity and utility of ImPACT scores.

CONCLUSION

Clinicians must consider the benefit of ImPACT testing for their patients on a case-by-case scenario and must take the psychometric properties of the test into account when interpreting results.

Fighting to keep a sport safe: toward a structured and sport-specific return to play protocol

Combat sports are growing in popularity, viewership, and participation. The nature of these sports involves repetitive head contact, yet unlike most other professional contact sports, there are no endorsed guidelines or mandates for graduated and systematic return to play following concussion. Here, we review the literature related to concussion and fighting sports, and propose guidelines for concussion management and safe return to play following concussion.

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.

Clinical Evaluation of the Concussed Athlete: A View From the Sideline

CONTEXT

The sideline assessment of concussion is challenging, given its variable presentations, the limited sensitivity and specificity of sideline assessment tools, and how the presentation of the injury evolves over time. In addition, the diagnostic process, as well as the tools used to assess and manage concussion, continue to progress as research and what we know about concussion advance. This paper focuses on the initial assessment on the sideline by reviewing the concussion-evaluation literature, drawing from clinical experience to emphasize a standardized approach, and underscoring the importance of both familiarity with the athlete and clinical judgment.

OBJECTIVE

To review the evidence regarding the clinical assessment of sport-related concussion on the sideline. Additional considerations included making same-day return-to-play decisions, the sensitivity and specificity of sideline testing, and the importance of ongoing assessment and follow-up of injured athletes.

DATA SOURCES

I conducted a systematic literature review of the assessment of concussion on the sideline. The PubMed and MEDLINE databases were searched using the key term athletic injuries with concussion and mild traumatic brain injury. The search was refined by adding the key terms sideline assessment and on-field assessment. In addition, select additional position statements and guidelines on concussion were included in the review.

RESULTS

The PubMed search using athletic injuries and concussion as key terms produced 1492 results. Refining the search by sideline assessment and on-field assessment produced 29 and 35 results, respectively. When athletic injuries and traumatic brain injury were combined, 1912 results were identified. Refining the search by sideline assessment and on-field assessment led to 28 and 35 results, respectively. Only papers that were English-language titles, original work, and limited to human participants and included sideline assessments of sport-related concussion in athletes older than 13 years were considered for this discussion. A total of 96 papers were reviewed, including systematic reviews, consensus guidelines, and position statements.

CONCLUSIONS

The sideline assessment of sport-related concussion is challenging given the elusiveness and variability of presentation, reliance on athlete-reported symptoms, and the varying specificity and sensitivity values of sideline assessment tools. In addition, the recognition of injury and assessment often occur in a time-pressured environment, requiring rapid disposition and decision making. Clinicians should begin the evaluation by assessing for cervical spine injury, intracranial bleeding, and other injuries that can present in a similar fashion or in addition to concussion. The sideline concussion evaluation should consist of a symptom assessment and a neurologic examination that addresses cognition (briefly), cranial nerve function, and balance. Emerging tools that assess visual tracking may provide additional information. The sensitivity and specificity of commonly implemented sideline assessment tools are generally good to very good, especially for symptom scores and cognitive evaluations performed within 48 hours of injury, and they are improved when a baseline evaluation is available for comparison. Serial assessments are often necessary as objective signs and symptoms may be delayed. A standardized assessment is paramount in evaluating the athlete with a suspected concussion, but there is no replacement for being familiar with the athlete and using clinical judgment when the athlete seems "not right" despite a "normal" sideline assessment. Ultimately, the clinician should err on the side of caution when making a return-to-play decision.

Sports-related concussions: diagnosis, complications, and current management strategies

Sports-related concussions (SRCs) are traumatic events that affect up to 3.8 million athletes per year. The initial diagnosis and management is often instituted on the field of play by coaches, athletic trainers, and team physicians. SRCs are usually transient episodes of neurological dysfunction following a traumatic impact, with most symptoms resolving in 7-10 days; however, a small percentage of patients will suffer protracted symptoms for years after the event and may develop chronic neurodegenerative disease. Rarely, SRCs are associated with complications, such as skull fractures, epidural or subdural hematomas, and edema requiring neurosurgical evaluation. Current standards of care are based on a paradigm of rest and gradual return to play, with decisions driven by subjective and objective information gleaned from a detailed history and physical examination. Advanced imaging techniques such as functional MRI, and detailed understanding of the complex pathophysiological process underlying SRCs and how they affect the athletes acutely and long-term, may change the way physicians treat athletes who suffer a concussion. It is hoped that these advances will allow a more accurate assessment of when an athlete is truly safe to return to play, decreasing the risk of secondary impact injuries, and provide avenues for therapeutic strategies targeting the complex biochemical cascade that results from a traumatic injury to the brain.

Three versus seven days to return-to-work after mild traumatic brain injury: a randomized parallel-group trial with neuropsychological assessment

Although most patients with a mild traumatic brain injury (mTBI) recover within days to weeks, some experience persistent physical, cognitive and emotional symptoms, often described as post-concussion syndrome (PCS). The optimal recovery time including return-to-work (RTW) after mTBI is unclear. In this single-centre parallel-group trial, patients assigned three days (3D-group) or seven days (7D-group) sick leave were compared with a comprehensive neuropsychological test battery including the Post-Concussion Symptom Scale (PCSS) within one week, after three and 12 months post-injury. The influence of the effective time until RTW on post-concussional symptoms and cognitive performance was analysed. The 3D-group rated significantly higher mean scores in some PCSS symptoms, tended to fulfil diagnosis criteria of PCS more often and showed better cognitive performance in several neuropsychological test scores than the 7D-group at all three time-points of follow-up. Overall, patients returned to work 11.35 d post-injury, thus distinctly above both recommended sick leaves. There was a trend for longer sick leave in patients randomized into the 3D-group. Further analyses revealed that the group with an absolute RTW within one week showed lower symptom severity in fatigue at 3 and 12 months, less PCS and faster performance in fine motor speed at 12 months than the group with an absolute RTW after one week. Our data underline the heterogeneity of mTBI and show that acute and sub-acute symptoms are not prognostic factors for neuropsychological outcome at one year. Later, ability to work seems to be prognostic for long-term occurrence of PCS.

Preliminary investigation of Brain Network Activation (BNA) and its clinical utility in sport-related concussion

Background: The clinical diagnosis and management of patients with sport-related concussion is largely dependent on subjectively reported symptoms, clinical examinations, cognitive, balance, vestibular and oculomotor testing. Consequently, there is an unmet need for objective assessment tools that can identify the injury from a physiological perspective and add an important layer of information to the clinician’s decision-making process.

Objective: The goal of the study was to evaluate the clinical utility of the EEG-based tool named Brain Network Activation (BNA) as a longitudinal assessment method of brain function in the management of young athletes with concussion.

Methods: Athletes with concussion (n = 86) and age-matched controls (n = 81) were evaluated at four time points with symptom questionnaires and BNA. BNA scores were calculated by comparing functional networks to a previously defined normative reference brain network model to the same cognitive task.

Results: Subjects above 16 years of age exhibited a significant decrease in BNA scores immediately following injury, as well as notable changes in functional network activity, relative to the controls. Three representative case studies of the tested population are discussed in detail, to demonstrate the clinical utility of BNA.

Conclusion: The data support the utility of BNA to augment clinical examinations, symptoms and additional tests by providing an effective method for evaluating objective electrophysiological changes associated with sport-related concussions.

Usability evaluation of the SMART application for youth with mTBI

OBJECTIVE

There is a dearth of evidence-based treatments available to address the significant morbidity associated with mild traumatic brain injury (mTBI). To address this gap, we designed a novel user-friendly, web-based application. We describe the preliminary evaluation of feasibility and usability of the application to promote recovery following mTBI in youth, the Self-Monitoring Activity-Restriction and Relaxation Treatment (SMART). SMART incorporates real-time recommendations for individualized symptom management and activity restriction along with training in cognitive-behavioral coping strategies.

METHODS

We conducted a usability evaluation to assess and modify the SMART system prior to further study and deployment. Children ages 11-18 years presenting to the emergency department were recruited after symptoms resolved. Usability was assessed using a 60-min think-aloud protocol of teens and parents describing their interaction with the application. Upon completion of the tasks, each participant also completed the system usability scale (SUS).

RESULTS

We performed tests with 4 parent/child dyads. The average age of the children was 13 years (standard deviation=1.8). The parents were an average of 41.5 years old (standard deviation=6.2). Research revealed that the participants were enthusiastic about the interactive portions of the tool particularly the video based sessions. Parents were concerned about the speed at which their child might move through the program and the children thought that the system required large amounts of reading. Based on user feedback, researchers modified SMART to include an audio file in every module and improved the system's aesthetic properties. The mean SUS score was 85, with high SUS scores (>68) indicating satisfactory usability.

CONCLUSION

High initial usability and favorable user feedback provide a foundation for further iterative development and testing of the SMART application as a tool for managing recovery from concussion.

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.

Abnormalities in Diffusional Kurtosis Metrics Related to Head Impact Exposure in a Season of High School Varsity Football

The purpose of this study was to determine whether the effects of cumulative head impacts during a season of high school football produce changes in diffusional kurtosis imaging (DKI) metrics in the absence of clinically diagnosed concussion. Subjects were recruited from a high school football team and were outfitted with the Head Impact Telemetry System (HITS) during all practices and games. Biomechanical head impact exposure metrics were calculated, including: total impacts, summed acceleration, and Risk Weighted Cumulative Exposure (RWE). Twenty-four players completed pre- and post-season magnetic resonance imaging, including DKI; players who experienced clinical concussion were excluded. Fourteen subjects completed pre- and post-season Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). DKI-derived metrics included mean kurtosis (MK), axial kurtosis (K axial), and radial kurtosis (K radial), and white matter modeling (WMM) parameters included axonal water fraction, tortuosity of the extra-axonal space, extra-axonal diffusivity (D_e axial and radial), and intra-axonal diffusivity (D_a). These metrics were used to determine the total number of abnormal voxels, defined as 2 standard deviations above or below the group mean. Linear regression analysis revealed a statistically significant relationship between RWE combined probability (RWE_CP) and MK. Secondary analysis of other DKI-derived and WMM metrics demonstrated statistically significant linear relationships with RWE_CP after covariate adjustment. These results were compared with the results of DTI-derived metrics from the same imaging sessions in this exact same cohort. Several of the DKI-derived scalars (D_a, MK, K axial, and K radial) explained more variance, compared with RWE_CP, suggesting that DKI may be more sensitive to subconcussive head impacts. No significant relationships between DKI-derived metrics and ImPACT measures were found. It is important to note that the pathological implications of these metrics are not well understood. In summary, we demonstrate a single season of high school football can produce DKI measurable changes in the absence of clinically diagnosed concussion.

A practical guide to evaluating sleep disturbance in concussion patients

Purpose of review

To provide an introduction and review of sleep metrics appropriate for use with an outpatient concussed population.

Recent findings

Although sleep issues are frequently identified in concussion, sleep disturbance is rarely assessed in outpatient settings. Given that sleep disturbance may be indicative of, or contribute to, delayed neurocognitive recovery, measurement tools for sleep, rest, and activity behavior may be of both practical and research utility.

Summary

Because sleep disturbance symptoms may vary between or within an individual throughout the course of recovery, it is recommended that sleep be measured at regular intervals over the entirety of recovery. Included is a discussion on how to select appropriate measures based on patient symptomology in addition to common practical concerns. Additional clinical considerations, a review of traditional pencil and paper methods of continuous sleep behavior monitoring, as well as technologies for measuring sleep and activity behavior are also included.

Are There Subconcussive Neuropsychological Effects in Youth Sports? An Exploratory Study of High- and Low-Contact Sports

This exploratory study was designed to examine the neuropsychological effects of sports-related head trauma-specifically, repetitive subconcussive impacts or head blows that do not result in a diagnosable concussion. The researchers compared the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) neurocognitive test scores of 2 groups of nonconcussed youth athletes (n = 282), grouped according to the frequency of concussions in their respective sports, with the assumption that more subconcussive impacts occur in sports in which there are more reported concussions. The results indicated that high-contact-sport (football) athletes had significantly poorer performance in processing speed and reaction time compared with athletes in low-contact sports (wrestling, soccer, baseball, judo, and basketball). This study into the effects of repetitive subconcussive head trauma tentatively raises concern that participation in high-contact sports, even without evidence of a diagnosable concussion, could result in lowered neuropsychological functioning among high school athletes. Limitations of this exploratory research effort are discussed.

Relationship Between Cognitive Assessment and Balance Measures in Adolescents Referred for Vestibular Physical Therapy After Concussion

OBJECTIVE

To examine the relationship between cognitive and balance performance in adolescents with concussion.

DESIGN

Retrospective case series.

SETTING

Tertiary.

PATIENTS

Sixty patients.

INTERVENTIONS

Correlation analyses were performed to describe the relationship between symptoms, cognitive measure, and balance measure at the time of initiation of vestibular physical therapy.

MAIN OUTCOME MEASURES

Cognitive performance was assessed using the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT). The dizziness and balance function measures included dizziness severity rating, Activities-specific Balance Confidence scale (ABC), Dizziness Handicap Inventory (DHI), Functional Gait Assessment, gait speed, Timed "UP and GO," Five Times Sit to Stand, and Sensory Organization Test (SOT). To account for multiple comparisons, the False Discovery Rate method was used.

RESULTS

Performance measures of balance were significantly correlated with cognitive measures. Greater total symptom scores were related to greater impairment in the ABC and DHI (r = 0.35-0.39, P ≤ 0.008) and worse performance in condition 2 of the SOT (r = -0.48, P = 0.004). Among the ImPACT composite scores, lower memory scores were correlated with impaired balance performance measures (r = 0.37-0.59, P ≤ 0.012). Lower visual memory was also correlated with worse ABC scores.

CONCLUSIONS

The significant relationships reported between the cognitive performance scores and balance measures may reflect that similar levels of functioning exist across domains in individuals with protracted recovery who receive vestibular physical therapy.

CLINICAL RELEVANCE

The weak-to-moderate relationships warrant the continuous use of multiple domains of assessment. A better understanding to the relationships between the domains of functioning after concussion may improve the overall management approach for adolescents with concussion.

Developing guidelines for return to play: consensus and evidence-based approaches

BACKGROUND

Sports-related concussions are commonplace at all levels of play and across all age groups. The dynamic, evolving nature of this injury coupled with a lack of objective biomarkers creates a challenging management issue for the sports medicine team. Athletes who return to play following a concussion are known to be at higher risk for an additional brain injury, which necessitates a careful, informed return to play (RTP) process.

AIM

The goal of this paper is to outline historical attempts at developing RTP guidelines and trace their evolution over time, culminating in a discussion of the process and outcomes of the most recent consensus statements/guidelines published by the international Concussion In Sport Group (CISG), the American Academy of Neurology (AAN), the National Athletic Trainers' Association, and the 2013 Team Physician Consensus Statement Update.

METHOD

An evaluation of the pros and cons of these guidelines is presented along with suggestions for future directions. In addition, the Institute of Medicine recently conducted a comprehensive report outlining the current state of evidence regarding youth concussions, which provides specific recommendations for future research.

CONCLUSIONS

The different methodologies utilized in the development of consensus statements have distinct advantages and disadvantages, and both approaches add value to the everyday management of sports concussions. Importantly, the overall approach for management of sports concussion is remarkably similar using either consensus-based or formal evidence-based methods, which adds confidence to the current guidelines and allows practitioners to focus on accepted standards of clinical care. Moving forward, careful study designs need to be utilized to avoid bias in selection of research subjects, collection of data, and interpretation of results. Although useful, clinicians must venture beyond consensus statements to examine reviews of the literature that are published in much greater frequency than consensus statements.

Developmental and gender influences on executive function following concussion in youth hockey players

BACKGROUND

Concussion is the most common athletic injury in youth who are simultaneously undergoing rapid developmental changes in the brain, specifically the development of executive functions (EF). The developing brain is more vulnerable to concussive injury with a protracted and different trajectory of recovery than that of adults. Thus, there is a critical need to enhance understanding of how concussion affects EF in youth.

OBJECTIVE

To investigate the effects of age, gender and concussion history (i.e. concussion incidence, recency, severity) on EF in youth hockey players.

METHODS

This 3-year cross-sectional and longitudinal multiple cohort study examined data from 211 hockey players of 8-15 years of age. Mixed-effects modelling was used to examine the influence of age, gender and concussion on EF in youth athletes.

FINDINGS

Baseline analyses revealed significant age and gender effects on measures of EF. Multiple effects of concussion history on measures of cognitive flexibility (F = 2.48, p = 0.03) and psychomotor speed (F = 2.59, p = 0.04) were found.

IMPLICATIONS

This study highlights the impact of age, gender and concussion on EF in youth. These findings provide foundational knowledge to better manage cognitive sequelae following sports-related concussion.

Management of persistent postconcussion symptoms in youth: a randomised control trial protocol

INTRODUCTION

Current management of concussion consists of early education, rest until symptom free, with gradual return to school and physical activity protocols. Although this management strategy is effective for most youth who sustain a concussion, it is not an appropriate strategy for youth with persistent postconcussion symptoms. Prolonged rest and periods of restricted activity may place youth at risk for secondary issues and contribute to the chronicity of postconcussion symptoms. The purpose of this study is to evaluate the efficacy of an active rehabilitation protocol for youth who are slow to recover from concussion. It is hypothesised that an active rehabilitation intervention can reduce persistent postconcussion symptoms, improve function and facilitate return to activity. This article describes the research protocol.

METHODS AND ANALYSIS

This is a randomised clinical trial with blinded outcome measurement. Participants will be recruited and randomly assigned to 1 of 2 treatment groups, an active rehabilitation intervention or a standard care education group. Both groups will receive standard care education. However, the active rehabilitation group will participate in an additional low-intensity exercise programme consisting of aerobic, coordination and visualisation exercises. Both the active rehabilitation and the standard care education interventions will be 6 weeks in duration. The primary outcome measure is postconcussion symptoms. Secondary outcome measures include functional recovery (cognitive, motor, psychosocial and emotional functioning) and return to activity. Outcome measures will be administered preintervention and postintervention. The primary outcome measure will also be repeated 2 weeks into the intervention period.

ETHICS AND DISSEMINATION

This study has been approved by the Holland Bloorview Kids Rehabilitation Hospital research ethics board (REB # 13-459). The findings from this study will be shared with the general public, sport associations, relevant brain injury organisations and healthcare professionals.

TRIAL REGISTRATION NUMBER

NCT02257749.

Cognitive function and brain structure after recurrent mild traumatic brain injuries in young-to-middle-aged adults

Recurrent mild traumatic brain injuries (mTBIs) are regarded as an independent risk factor for developing dementia in later life. We here aimed to evaluate associations between recurrent mTBIs, cognition, and gray matter volume and microstructure as revealed by structural magnetic resonance imaging (MRI) in the chronic phase after mTBIs in young adulthood. We enrolled 20 young-to-middle-aged subjects, who reported two or more sports-related mTBIs, with the last mTBI > 6 months prior to study enrolment (mTBI group), and 21 age-, sex- and education matched controls with no history of mTBI (control group). All participants received comprehensive neuropsychological testing, and high resolution T1-weighted and diffusion tensor MRI in order to assess cortical thickness (CT) and microstructure, hippocampal volume, and ventricle size. Compared to the control group, subjects of the mTBI group presented with lower CT within the right temporal lobe and left insula using an a priori region of interest approach. Higher number of mTBIs was associated with lower CT in bilateral insula, right middle temporal gyrus and right entorhinal area. Our results suggest persistent detrimental effects of recurrent mTBIs on CT already in young-to-middle-aged adults. If additional structural deterioration occurs during aging, subtle neuropsychological decline may progress to clinically overt dementia earlier than in age-matched controls, a hypothesis to be assessed in future prospective trials.

A longitudinal pilot study of depressive symptoms in concussed and injured/nonconcussed National Collegiate Athletic Association Division I student-athletes

CONTEXT

Depression, which affects millions of Americans each year, among them collegiate student-athletes, can be caused by a wide range of circumstances, including sport-related injuries.

OBJECTIVE

To longitudinally examine the extent to which National Collegiate Athletic Association Division I student-athletes demonstrated postinjury depressive symptoms.

DESIGN

Descriptive epidemiologic study.

SETTING

National Collegiate Athletic Association Division I collegiate athletics.

PATIENTS OR OTHER PARTICIPANTS

Concussed, injured/nonconcussed, and healthy Division I collegiate student-athletes (aged 18-22 years) competing in men's basketball, football, and wrestling and women's basketball, soccer, and volleyball.

MAIN OUTCOME MEASURE(S)

Participants completed the Center for Epidemiologic Studies Depression Scale at baseline and at 1 week, 1 month, and 3 months postinjury. We measured differences in depressive scores among concussed, injured/nonconcussed, and healthy participants. Longitudinal changes in postconcussion depressive symptoms were also examined.

RESULTS

No differences in baseline depressive symptoms among subgroups were noted. After an increase between baseline and 1 week (4.3, 95% confidence interval [CI] = 0.41, 8.16, P = .02), depressive symptoms in the concussion group decreased between 1 week and 1 month (-2.7, 95% CI = -4.96, -0.47, P = .01) and between 1 week and 3 months (-4.0, 95% CI = -6.50, -1.49, P = .004). The injured/nonconcussed group showed differences between baseline and 1 week (4.6, 95% CI = 1.08, 8.17, P = .009) and between baseline and 1 month (3.2, 95% CI = -0.05, 6.30, P = .03). No significant differences were present in depressive symptoms between concussed participants and injured/nonconcussed participants at any of the postinjury time points.

CONCLUSIONS

Depression may present as a postinjury sequela in Division I collegiate athletes. Athletes who sustain a concussion or other injury resulting in time lost from practice or competition need to be observed carefully for signs and symptoms that may indicate depression. Tools such as the Center for Epidemiologic Studies Depression Scale can be valuable in helping clinicians to recognize and manage depressive symptoms in these individuals.

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.

Effect of sex on symptoms and return to baseline in sport-related concussion

OBJECT

Sport-related concussions (SRCs) among youth athletes represent a significant public health concern. Prior research suggests that females fare worse symptomatically after an SRC. The authors aimed to assess sex differences in number, severity, and resolution of postconcussive symptoms using reliable change index (RCI) methodology applied to days to return to symptom baseline.

METHODS

Between 2009 and 2011, 740 youth athletes completed valid neurocognitive and symptom testing before and after an SRC using Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). A total of 122 female and 122 male athletes were matched on number of prior concussions, age, and number of days to first postconcussion test. At baseline and postconcussion, the authors compared each of the individual 22 symptoms on ImPACT to calculate individual symptom severity and aggregate symptom severity, or the Total Symptom Score (TSS). When comparing individual symptoms, the significance level for the comparison of each symptom was set at 0.05/22 = 0.0023. When comparing aggregate symptom severity, or TSS, a single value was compared, requiring an alpha set to 0.05. The number of days to return to baseline TSS was compared using RCI methods set at the 80% confidence interval, equal to a raw score point value of 9.18 on the TSS.

RESULTS

At baseline, females reported a greater severity for the symptom, "sleeping less than usual," compared with males (0.88 ± 1.49 vs 0.31 ± 0.86, p < 0.001). However, no other individual symptom severity differences were noted before or after SRC. At baseline, females exhibited a statistically significant greater aggregate symptom severity than males (7.24 ± 10.22 vs 4.10 ± 6.52, p = 0.005). Greater aggregate symptom severity for females was also found postconcussion (21.38 ± 19.02 vs 16.80 ± 17.07, p = 0.049). Females took longer to return to baseline TSS (9.1 ± 7.1 days vs 7.0 ± 5.1 days, p = 0.013).

CONCLUSIONS

The results of this retrospective study indicate that females endorse a greater severity of symptoms at baseline and postconcussion than males without significantly different symptom profiles. Furthermore, after suffering an SRC, females take longer to return to their baseline symptom level.

Does age affect symptom recovery after sports-related concussion? A study of high school and college athletes

OBJECT

Sport-related concussions (SRCs) in high school and college athletes represent a significant public health concern. Research suggests that younger athletes fare worse symptomatically than older athletes after an SRC. Using reliable change index (RCI) methodology, the authors conducted a study to determine if there are age-related differences in number, severity, and resolution of postconcussion symptoms.

METHODS

Between 2009 and 2011, baseline measures of neurocognitive functions and symptoms in high school and college athletes were entered into a regional database. Seven hundred forty of these athletes later sustained an SRC. Ninety-two athletes in the 13- to 16-year-old group and 92 athletes in the 18- to 22-year-old group were matched for number of prior concussions, sex, biopsychosocial variables, and days to first postconcussion testing and symptom assessment. A nonparametric Mann-Whitney U-test was used to compare the severity of each of 22 symptoms comprising the Total Symptom Scale (TSS) at baseline and first postconcussion test. To obtain a family-wise p value of 0.05 for each test, the significance level for each symptom comparison was set at an alpha of 0.05/22 = 0.0023. The number of days to return to baseline TSS score was compared using the RCI methodology, set at the 80% confidence interval, equal to a change in raw score of 9.18 points on the TSS.

RESULTS

There was no statistically significant difference in symptom presence, symptom severity, and total symptoms between the age groups at baseline or at postconcussion testing. There was no statistically significant difference in return to baseline symptom scores between the age groups.

CONCLUSIONS

Using RCI methodology, there was no statistically significant difference between younger and older athletes in return to baseline symptoms postconcussion.

Concussion-assessment and -management techniques used by athletic trainers

CONTEXT

Understanding concussion-assessmment and -management practices that athletic trainers (ATs) currently use will allow clinicians to identify potential strategies for enhancing the quality of care provided to patients.

OBJECTIVE

To assess current clinical concussion diagnostic and return-to-participation practices among ATs.

DESIGN

Cross-sectional study.

SETTING

Web-based survey.

PATIENTS OR OTHER PARTICIPANTS

A link to the survey was sent randomly to a convenience sample of 3222 members of the National Athletic Trainers' Association. A total of 1053 (32.7%) certified ATs (experience as an AT = 11.2 ± 9.1 years) responded to the survey.

INTERVENTION(S)

Prospective participants received electronic correspondence informing them of the purpose of the study and providing a link to the Web-based survey instrument. A reminder e-mail was sent approximately 6 weeks later, and the survey remained online for a total of 8 weeks.

MAIN OUTCOME MEASURE(S)

We collected information on the annual number of concussions assessed and tools employed to diagnose, manage, and safely return an athlete to participation. Descriptive statistics were computed for each variable.

RESULTS

Participants reported observing 10.7 ± 11.0 concussions per year. Clinical examination (n = 743, 70.6%) was the most commonly reported means for evaluating and diagnosing concussion. Less than half of our respondents employed the Standardized Assessment of Concussion (n = 467, 44.3%), any variation of the Romberg test (n = 461, 43.8%), and computerized neuropsychological testing (n = 459, 43.6%). Clinical examination (n = 773, 73.4%), return-to-participation guidelines (n = 713, 67.7%), physician recommendation (n = 660, 62.7%), or player self-report (n = 447, 42.5%) contributed to the return-to-participation decisions of ATs. Only 20.8% (n = 219) of ATs reported using all 3 recommended domains of the concussion battery.

CONCLUSIONS

Our study demonstrated a growth in the number of ATs incorporating objective clinical measures of concussion as a part of their concussion management. Conversely, fewer ATs reported using a standard clinical examination in their concussion assessment. These findings suggest ATs must continue to increase their use of both objective concussion assessment tools and the standard clinical examination.

Practice effects reveal visuomotor vulnerability in school and university rugby players

This article reports on three pre- versus post-season prospective studies in which male university and high school contact sport players predominantly of Rugby Union (hereafter rugby) were compared with age, education, and IQ equivalent non-contact sport controls on the ImPACT (Immediate Postconcussion Assessment and Cognitive Testing) test. All analyses revealed a relative absence of practice effects on the Visual Motor Speed (VMS) composite for contact sport groups compared with controls. The VMS data for rugby players from each study were pooled and subjected to additional analysis (Rugby, n = 145; Controls, n = 106). Controls revealed significant improvement over the season (p < .001), whereas no learning effect was in evidence for rugby players whose performance remained the same (interaction effect, p = .028). It is apparent that practice effects have diagnostic potential in this context, implicating vulnerability on speeded visuomotor processing in association with participation in rugby. Pointers for further research and concussion management in the individual case are explored.

Baseline neurocognitive scores in athletes with attention deficit-spectrum disorders and/or learning disability

OBJECT

Up to 16% of children in the US between the ages of 3 and 17 years have either attention deficit-spectrum disorder or a learning disability (LD). Sports-related concussions among youth athletes represent a significant public health concern, and neurocognitive testing is a method to evaluate the severity of cognitive impairment and recovery after a sports-related concussion. The goal of this study was to assess baseline neurocognitive differences between athletes with attention deficit hyperactivity disorder (ADHD) and/or LD versus those with neither disorder and to establish normative data for these special populations.

METHODS

Between August 2007 and March 2012, 6636 young athletes underwent baseline neurocognitive testing performed using the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery. Of these participants, 90 had self-reported LD only, 262 had self-reported ADHD only, and 55 reported both. Those with ADHD and/or LD were matched with 407 participants with no history of ADHD or LD by age, sex, and number of prior concussions. The mean scores and SDs were calculated for each group to obtain normative values. A pairwise comparison between each diagnostic group was done to assess whether LD and/or ADHD diagnostic status predicted participants' baseline neurocognitive scores.

RESULTS

Participants with ADHD had significantly lower verbal memory, visual memory, and visual motor processing speed scores, along with significantly higher reaction time, impulse control, and symptom scores compared with those without LD or ADHD. Participants with LD had similar results, with significantly lower verbal memory, visual memory, and visual motor processing speed scores, higher reaction time and symptom score, but did not differ in their impulse control score compared with those without LD or ADHD. Participants with both LD and ADHD had a significantly lower visual motor speed score and a significantly higher reaction time and symptom score than those without LD or ADHD, but did not differ with regard to the other composite scores.

CONCLUSIONS

Athletes with ADHD and/or LD have lower baseline ImPACT neurocognitive scores compared with athletes without ADHD and LD. Preliminary normative neurocognitive data for these special populations are provided.

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.

Magnetoencephalographic virtual recording: a novel diagnostic tool for concussion

OBJECT

Heightened recognition of the prevalence and significance of head injury in sports and in combat veterans has brought increased attention to the physiological and behavioral consequences of concussion. Current clinical practice is in part dependent on patient self-report as the basis for medical decisions and treatment. Magnetoencephalography (MEG) shows promise in the assessment of the pathophysiological derangements in concussion. The authors have developed a novel MEG-based neuroimaging strategy to provide objective, noninvasive, diagnostic information in neurological disorders. In the current study the authors demonstrate a novel task protocol and then assess MEG virtual recordings obtained during task performance as a diagnostic tool for concussion.

METHODS

Ten individuals (5 control volunteers and 5 patients with a history of concussion) were enrolled in this pilot study. All participants underwent an MEG evaluation during performance of a language/spatial task. Each individual produced 960 responses to 320 sentence stimuli; 0.3 sec of MEG data from each word presentation and each response were analyzed: the data from each participant were classified using a rule constructed from the data obtained from the other 9 participants.

RESULTS

Analysis of response times showed significant differences (p < 10(-4)) between concussed and normal groups, demonstrating the sensitivity of the task. The MEG measures enabled the correct classification of 8 of 10 individuals as concussed versus nonconcussed (p = 0.055). Analysis of single-trial data classified 70% of trials correctly (p < 10(-10)). Concussed patients showed increased activation in the occipitoparietal and temporal regions during evaluation.

CONCLUSIONS

These pilot findings are the first evidence of the utility of MEG virtual recording in diagnosing concussion. With further refinements, MEG virtual recordings may represent a noninvasive test to diagnose concussion and monitor its resolution.

Dehydration and performance on clinical concussion measures in collegiate wrestlers

CONTEXT

The effects of dehydration induced by wrestling-related weight-cutting tactics on clinical concussion outcomes, such as neurocognitive function, balance performance, and symptoms, have not been adequately studied.

OBJECTIVE

To evaluate the effects of dehydration on the outcome of clinical concussion measures in National Collegiate Athletic Association Division I collegiate wrestlers.

DESIGN

Repeated-measures design.

SETTING

Clinical research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Thirty-two Division I healthy collegiate male wrestlers (age = 20.0 ± 1.4 years; height = 175.0 ± 7.5 cm; baseline mass = 79.2 ± 12.6 kg).

INTERVENTION(S)

Participants completed preseason concussion baseline testing in early September. Weight and urine samples were also collected at this time. All participants reported to prewrestling practice and postwrestling practice for the same test battery and protocol in mid-October. They had begun practicing weight-cutting tactics a day before prepractice and postpractice testing. Differences between these measures permitted us to evaluate how dehydration and weight-cutting tactics affected concussion measures.

MAIN OUTCOME MEASURES

Sport Concussion Assessment Tool 2 (SCAT2), Balance Error Scoring System, Graded Symptom Checklist, and Simple Reaction Time scores. The Simple Reaction Time was measured using the Automated Neuropsychological Assessment Metrics.

RESULTS

The SCAT2 measurements were lower at prepractice (P = .002) and postpractice (P < .001) when compared with baseline. The BESS error scores were higher at postpractice when compared with baseline (P = .015). The GSC severity scores were higher at prepractice (P = .011) and postpractice (P < .001) than at baseline and at postpractice when than at prepractice (P = .003). The number of Graded Symptom Checklist symptoms reported was also higher at prepractice (P = .036) and postpractice (P < .001) when compared with baseline, and at postpractice when compared with prepractice (P = .003).

CONCLUSIONS

Our results suggest that it is important for wrestlers to be evaluated in a euhydrated state to ensure that dehydration is not influencing the outcome of the clinical measures.

A Case for Mental and Physical Rest in Youth Sports Concussion: It's Never too Late

Over the past decade, there has been a considerable increase in research on, and media attention to, sports-related concussion. However, despite accurate diagnosis, effective treatment and management of sports-related concussion have remained a challenge. There are approximately 1.8 million traumatic brain injuries in the United States annually (Faul et al., 2010) and emergency department pediatric visits for suspected concussion have doubled in the past decade (Bakhos et al., 2010). However, health care providers and medical researchers have yet to offer an effective, reliable evidence-based treatment for concussive brain injury. The Zurich 2008 Consensus Statement on Concussion in Sport codified the prescription for cognitive and physical rest immediately following a concussion based on clinical acumen and common sense (McCrory et al., 2009). Currently, rest is the considered the best immediate treatment for concussion. Other supportive and anecdotal treatments are often applied throughout the post-concussive recovery process to address persistent symptoms. The need for empirical research to translate current guidelines for rest into evidence-based treatment protocols is essential. A recent study evaluated the efficacy of comprehensive rest and concluded that such rest may be helpful whether applied soon after a concussion or weeks to months later (Moser et al., 2012). Here, we present a case illustrating the effectiveness of rest in a youth athlete, commenced after experiencing 13 months of post-concussion symptoms. There appears to be value in applying a specific period of cognitive and physical rest following concussion, whether immediately or later in the recovery phase.

The relationship among neurocognitive performances and biopsychosocial characteristics of elite National Football League draft picks: an exploratory investigation

Sports neuropsychology has emerged as a specialty area within the field of clinical neuropsychology. The role of the sports neuropsychologist, rooted in baseline and post-concussion testing, has evolved to include other clinical domains, including the clinical assessment of potential draft picks. There is no published information on the neurocognitive characteristics of these draft picks. We sought to determine whether elite NFL draft picks differed from NFL roster athletes on neurocognitive (ImPACT) and biopsychosocial characteristics, and given that no published data exists for this population, adopted null hypotheses. Null hypotheses were rejected for two of the four ImPACT scores, as elite draft picks scored higher on measures of visual motor speed and reaction time than roster NFL athletes. Subtle but distinct neurocognitive differences are noted when comparing elite NFL draft picks with norms from a cumulative roster of a single NFL team.

Response to acute concussive injury in soccer players: is gender a modifying factor?

OBJECT

Several studies have suggested a gender difference in response to sports-related concussion (SRC). The Concussion in Sport group did not include gender as a modifying factor in SRC, concluding that the evidence at that point was equivocal. In the present study the authors endeavored to assess acute neurocognitive and symptom responses to an SRC in equivalent cohorts of male and female soccer players. The authors hypothesized that female athletes would experience greater levels of acute symptoms and neurocognitive impairment than males.

METHODS

Baseline symptom and neurocognitive scores were determined in 40 male and 40 female soccer players by using the Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) scale prior to any SRC. After sustaining an SRC, each athlete completed postconcussion ImPACT tests and was carefully matched on a wide array of biopsychosocial variables. Baseline symptom and neurocognitive test scores were compared, and their acute symptoms and neurocognitive responses to concussive injury were assessed.

RESULTS

Specific a priori hypotheses about differences between males and females at baseline and at postconcussion measurements of verbal and visual memory ImPACT scores were evaluated according to simple main effects of the gender variable and according to baseline-to-postconcussion main effect and interaction of 2 × 2 split-plot ANOVA. Neither the interaction nor the main effects nor the simple main effects for either ImPACT variable were found to be statistically significant. Exploratory ANOVAs applied to the remaining ImPACT variables of visualmotor speed, reaction time, impulse control, and symptom total scores revealed only a single statistically significant baseline-to-postconcussion main effect for the symptom total.

CONCLUSIONS

The results failed to replicate prior findings of gender-specific baseline neurocognitive differences in verbal and visual memory. The findings also indicated no differential gender-based acute response to concussion (symptoms or neurocognitive scores) among high school soccer players. The implications of these findings for the inclusion of gender as a modifying factor in this tightly matched cohort are addressed. Potential explanations for the null findings are discussed.

Recovery from sports-related concussion: Days to return to neurocognitive baseline in adolescents versus young adults

BACKGROUND

Sports-related concussions (SRC) among high school and collegiate athletes represent a significant public health concern. The Concussion in Sport Group (CIS) recommended greater caution regarding return to play with children and adolescents. We hypothesized that younger athletes would take longer to return to neurocognitive baseline than older athletes after a SRC.

METHODS

Two hundred adolescent and young adult athletes who suffered a SRC were included in our clinical research cohort. Of the total participants, 100 were assigned to the 13-16 year age group and 100 to the 18-22 year age group and were matched on the number of prior concussions. Each participant completed baseline and postconcussion neurocognitive testing using the Immediate Post-Concussion assessment and Cognitive Testing (ImPACT) test battery. Return to baseline was defined operationally as post-concussion neurocognitive and symptom scores being equivalent to baseline using reliable change index (RCI) criteria. For each group, the average number of days to return to cognitive and symptom baseline were calculated. Independent sample t-tests were used to compare the mean number of days to return to baseline.

RESULTS

Significant differences were found for days to return to baseline between 13-16 year olds and 18-22 year olds in three out of four neurocognitive measures and on the total symptom score. The average number of days to return to baseline was greater for 13-16 year olds than for 18-22 year olds on the following variables: Verbal memory (7.2 vs. 4.7, P = 0.001), visual memory (7.1 vs. 4.7, P = 0.002), reaction time (7.2 vs. 5.1 P = 0.01), and postconcussion symptom scale (8.1 vs. 6.1, P = 0.026). In both groups, greater than 90% of athletes returned to neurocognitive and symptom baseline within 1 month.

CONCLUSIONS

Our results in this clinical research study show that in SRC, athletes 13-16 years old take longer to return to their neurocognitive and symptom baselines than athletes 18-22 years old.