The utility of post-concussion neuropsychological data in identifying cognitive change following sports-related MTBI in the absence of baseline data

The Evaluation and Management of Concussion to Optimize Safe Recovery

Concussion is a mild traumatic brain injury causing temporary neurologic dysfunction. Symptoms following concussion are variable and generally are expected to resolve within about 1 month, but some patients experience persistent and prolonged symptoms. An early return to safe, symptom-limited activity is now favored, using targeted rehabilitation and treatments. Accommodations may be needed to facilitate return-to-school and work following concussion. Athletes should not be cleared for a full return to sport until they have recovered from a concussion and completed a return-to-play progression, in addition to returning to work/school fully.

Exploring the association between cognitive activity and symptom resolution following concussion in adolescents aged 11-17 years

OBJECTIVE

As opposed to postconcussion physical activity, the potential influence of cognitive activity on concussion recovery is not well characterised. This study evaluated the intensity and duration of daily cognitive activity reported by adolescents following concussion and examined the associations between these daily cognitive activities and postconcussion symptom duration.

METHODS

This study prospectively enrolled adolescents aged 11-17 years with a physician-confirmed concussion diagnosis within 72 hours of injury from the emergency department and affiliated concussion clinics. Participants were followed daily until symptom resolution or a maximum of 45 days postinjury to record their daily cognitive activity (intensity and duration) and postconcussion symptom scores.

RESULTS

Participants (n=83) sustained their concussion mostly during sports (84%), had a mean age of 14.2 years, and were primarily male (65%) and white (72%). Participants reported an average of 191 (SD=148), 166 (SD=151) and 38 (SD=61) minutes of low-intensity, moderate-intensity and high-intensity daily cognitive activity postconcussion while still being symptomatic. Every 10 standardised minutes per hour increase in moderate-intensity or high-intensity cognitive activities postconcussion was associated with a 22% greater rate of symptom resolution (adjusted hazard ratio (aHR) 1.22, 95% CI 1.01 to 1.47). Additionally, each extra day's delay in returning to school postconcussion was associated with an 8% lower rate of symptom resolution (aHR 0.92, 95% CI 0.85 to 0.99).

CONCLUSION

In adolescents with concussion, more moderate-high intensity cognitive activity is associated with faster symptom resolution, and a delayed return to school is associated with slower symptom resolution. However, these relationships may be bidirectional and do not necessarily imply causality. Randomised controlled trials are needed to determine if exposure to early cognitive activity can promote concussion recovery in adolescents.

National Athletic Trainers' Association Bridge Statement: Management of Sport-Related Concussion

OBJECTIVE

To provide athletic trainers and team physicians with updated recommendations to the 2014 National Athletic Trainers' Association (NATA) concussion position statement regarding concussion management, specifically in the areas of education, assessment, prognostic factors, mental health, return to academics, physical activity, rest, treatment, and return to sport.

BACKGROUND

Athletic trainers have benefited from the 2 previous NATA position statements on concussion management, and although the most recent NATA position statement is a decade old, knowledge gains in the medical literature warrant updating several (but not all) recommendations. Furthermore, in various areas of the body of literature, current evidence now exists to address items not adequately addressed in the 2014 statement, necessitating the new recommendations. This document therefore serves as a bridge from the 2014 position statement to the current state of concussion evidence, recommendations from other organizations, and discrepancies between policy and practice.

RECOMMENDATIONS

These recommendations are intended to update the state of the evidence concerning the management of patients with sport-related concussion, specifically in the areas of education; assessment advances; prognostic recovery indicators; mental health considerations; academic considerations; and exercise, activity, and rehabilitation management strategies.

Neurocognitive Concussion Test Performance for Student Athletes on the Autism Spectrum

OBJECTIVE

To examine baseline neurocognitive functioning among adolescent athletes on the autism spectrum based on self-reported level of academic performance.

METHOD

Participants in this cross-sectional, observational study were 6,441 adolescent athletes with a self-reported diagnosis of autism who completed pre-season neurocognitive testing using Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT); 4,742 reported a co-occurring learning disorder (LD), and 6,612 individuals without autism or LD were included as a control group. The majority (57%) self-reported Average Academic Performance, 39% Above Average, and 4% Below Average performance.

RESULTS

Athletes with self-reported autism (with or without LD; 12.2%) were 2.74x (95% CI: 2.17-2.82) more likely to fall below cutoffs for ImPACT Embedded Invalidity Indicators (EVIs), with a significant interaction between self-reported Diagnosis and Academic Performance; individuals with co-occurring autism and LD who reported Below Average Academic Performance had the greatest likelihood of scoring below cutoffs (22%), followed by ASD without LD (14.8%) and Controls (14.6%) with Below Average Academic Performance. Analyses of variance (ANOVAs) revealed main effects of Diagnosis and Academic Performance on neurocognitive performance, with interactions on all ImPACT Composite Scores except Processing Speed.

CONCLUSION

Athletes with self-reported ASD are more likely to fall below ImPACT EVIs and score worse on ImPACT, with greater likelihood/worse performance related to level of academic functioning. Academic performance should be considered when interpreting neurocognitive testing data, to best index neuropsychological functioning associated with concussion in this population. The current findings highlight the importance of individual participant baseline neuropsychological testing for individuals on the autism spectrum.

The prevalence and correlates of scores falling below ImPACT embedded validity indicators among adolescent student athletes

Objective: Valid performance on preseason baseline neurocognitive testing is essential for accurate comparison between preseason and post-concussion test results. Immediate Post-Concussion and Cognitive Testing (ImPACT) is commonly used to measure baseline neurocognitive function in athletes. We examined the prevalence of invalid performance on ImPACT baseline testing and identified correlates of invalid performance. Method: The sample included 66,998 adolescents (ages 14-18, M = 15.51 years, SD = 1.22) who completed ImPACT baseline tests between 2009 and 2019. Invalid performance was determined by the embedded validity indicators (EVI). Associations between invalid performance, demographic characteristics, and health conditions were assessed using chi-square tests and odds ratios (ORs). Results: Overall, 7.2% of adolescents had baseline tests identified as invalid by one or more of the EVIs. Individual validity indicators classified between 0.5% and 3.7% tests as invalid. Higher frequencies of invalid scores were observed among youth with neurodevelopmental, academic, and medical conditions. Youth who reported having learning disabilities (n = 3126), receiving special education (n = 3563), or problems with attention-deficit/hyperactivity disorder (ADHD; n = 5104) obtained invalid baselines at frequencies of 16.4%, 16.0%, and 11.1%, respectively. Moreover, youth who reported receiving treatment for a substance use disorder (n = 311) or epilepsy (n = 718) obtained invalid baselines at frequencies of 17.0% and 11.1%, respectively. Conclusions: The base rate of invalid performance on ImPACT's EVIs was approximately 7%, consistent with prior research. Adolescents self-reporting neurodevelopmental conditions, academic difficulties, or a history of treatment for medical conditions obtained invalid baseline tests at higher frequencies. More research is needed to better understand invalid scores in youth with pre-existing conditions.

Psychometric Properties of Computerized Cognitive Tools and Standard Neuropsychological Tests Used to Assess Sport Concussion: A Systematic Review

Athletic programs are more frequently turning to computerized cognitive tools in order to increase efficiencies in concussion assessment. However, assessment using a traditional neuropsychological test battery may provide a more comprehensive and individualized evaluation. Our goal was to inform sport clinicians of the best practices for concussion assessment through a systematic literature review describing the psychometric properties of standard neuropsychological tests and computerized tools. We conducted our search in relevant databases including Ovid Medline, Web of Science, PsycINFO, and Scopus. Journal articles were included if they evaluated psychometric properties (e.g., reliability, sensitivity) of a cognitive assessment within pure athlete samples (up to 30 days post-injury). Searches yielded 4,758 unique results. Ultimately, 103 articles met inclusion criteria, all of which focused on adolescent or young adult participants. Test-retest reliability estimates ranged from .14 to .93 for computerized tools and .02 to .95 for standard neuropsychological tests, with strongest correlations on processing speed tasks for both modalities, although processing speed tasks were most susceptible to practice effects. Reliability was improved with a 2-factor model (processing speed and memory) and by aggregating multiple baseline exams, yet remained below acceptable limits for some studies. Sensitivity to decreased cognitive performance within 72 h of injury ranged from 45%-93% for computerized tools and 18%-80% for standard neuropsychological test batteries. The method for classifying cognitive decline (normative comparison, reliable change indices, regression-based methods) affected sensitivity estimates. Combining computerized tools and standard neuropsychological tests with the strongest psychometric performance provides the greatest value in clinical assessment. To this end, future studies should evaluate the efficacy of hybrid test batteries comprised of top-performing measures from both modalities.

Does Frequency of Baseline Testing Influence Concussion Diagnostic Decision Making Among College Athletes

OBJECTIVE

Concussion is a growing public health concern given the large number of youth and collegiate athletes participating in collision sports. Sport-related concussions can have an adverse impact on student-athletes' health and academic performance. Athletic programs within academic organizations are motivated to employ the most effective and efficient diagnostic and recovery procedures to minimize the duration and impact of these symptoms on student-athletes' functioning. The present study sought to further our understanding regarding the value and frequency of conducting baseline assessments when evaluating sport-related concussions.

METHOD

A total of 41 athletes (24 men, 17 women) between the ages of 18 and 22 were evaluated following suspected concussive injury between 2015 and 2018. Post-injury test results were compared to baselines that had been collected either 1 or 2 years prior, and to normative data, to determine consistency in diagnostic outcomes.

RESULTS

Baseline test/retest reliability using Pearson's bivariate correlations revealed modest correlations on measures of verbal and visual memory (0.437-0.569) and very strong correlations on measures of reaction time and visual-motor speed (0.811-0.821). Meanwhile, minimal if any differences in clinical decision-making regarding the diagnostic outcome was observed when comparing post-injury test results to different baselines and to normative data.

CONCLUSIONS

Findings indicate that yearly baseline testing may not improve diagnostic accuracy, and in many cases, normative data may be adequate for decision-making. Additional research should evaluate the potential benefit of baseline testing in return-to-play decision-making among broader athletic populations.

Prevalence of invalid ImPACT baseline test results among high school athletes with invalidity and sandbagging indices

Objective: The comparison of baseline neuropsychological test results with post-concussion neuropsychological test results is a common practice to assess the aftermath of a sport-related concussion. The effectiveness of this approach is compromised when invalid baseline test performances occur. The present study was designed to assess the prevalence of invalid baseline test results of high school athletes, using the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). Method: A large sample of 8938 high school athletes' baseline test data were examined, including the four ImPACT Composite scores and three sets of embedded invalid indices: five ImPACT Invalidity Indicators, four ImPACT sandbagging red flags, and two ImPACT sandbagging subtest flags. Results: There were 8394 (93.91%) Valid scorers, who failed no Invalidity Indicators; 544 (6.09%) Invalid scorers, who failed at least one Invalidity Indicator, 2718 (30.41%) Red Flag scorers, who had at least one Red Flag score; and 4154 (46.47%) Subtest Flag scorers, who had at least one Subtest Flag score. Of the entire sample, 4485 (54.65%) failed at least one of the invalid indices. Conclusions: As in prior studies of high school athletes, the Invalidity Indicators identified a low portion (6.09%) of the athletes with invalid baseline test results, while other invalidity measures found 30.41% to 46.48% of the athletes producing questionable test results. The high rate of invalid test findings suggested in this research calls for greater efforts to improve the accuracy of baseline test results.

Beyond acute concussion assessment to office management: a systematic review informing the development of a Sport Concussion Office Assessment Tool (SCOAT6) for adults and children

OBJECTIVES

To systematically review the scientific literature regarding the assessment of sport-related concussion (SRC) in the subacute phase (3-30 days) and provide recommendations for developing a Sport Concussion Office Assessment Tool (SCOAT6).

DATA SOURCES

MEDLINE, Embase, PsycINFO, Cochrane CENTRAL, CINAHL, SPORTDiscus and Web of Science searched from 2001 to 2022. Data extracted included study design, population, definition of SRC diagnosis, outcome measure(s) and results.

ELIGIBILITY CRITERIA

(1) Original research, cohort studies, case-control studies, diagnostic accuracy and case series with samples >10; (2) SRC; (3) screening/technology that assessed SRC in the subacute period and (4) low risk of bias (ROB). ROB was performed using adapted Scottish Intercollegiate Guidelines Network criteria. Quality of evidence was evaluated using the Strength of Recommendation Taxonomy classification.

RESULTS

Of 9913 studies screened, 127 met inclusion, assessing 12 overlapping domains. Results were summarised narratively. Studies of acceptable (81) or high (2) quality were used to inform the SCOAT6, finding sufficient evidence for including the assessment of autonomic function, dual gait, vestibular ocular motor screening (VOMS) and mental health screening.

CONCLUSION

Current SRC tools have limited utility beyond 72 hours. Incorporation of a multimodal clinical assessment in the subacute phase of SRC may include symptom evaluation, orthostatic hypotension screen, verbal neurocognitive tests, cervical spine evaluation, neurological screen, Modified Balance Error Scoring System, single/dual task tandem gait, modified VOMS and provocative exercise tests. Screens for sleep disturbance, anxiety and depression are recommended. Studies to evaluate the psychometric properties, clinical feasibility in different environments and time frames are needed.

PROSPERO REGISTRATION NUMBER

CRD42020154787.

Sensitivity and Specificity of the ImPACT Neurocognitive Test in Collegiate Athletes and US Military Service Academy Cadets with ADHD and/or LD: Findings from the NCAA-DoD CARE Consortium

BACKGROUND AND OBJECTIVE

Computer-based neurocognitive tests are widely used in sport-related concussion management, but the performance of these tests is not well understood in the participant population with attention-deficit/hyperactivity disorder (ADHD) and/or learning disorder (LD). This research estimates the sensitivity and specificity performance of the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) computer-based neurocognitive test in identifying concussion in this population.

METHODS

Study participants consisted of collegiate university athletes and military service academy cadets from the National Collegiate Athletic Association-Department of Defense CARE Consortium who completed the ImPACT test between 2014 and 2021. Participants who self-identified as belonging to one of the subgroups of interest (ADHD with or without LD [ADHD:LD+/-], LD with or without ADHD [LD:ADHD+/-], ADHD and/or LD [ADHD a/o LD]) and completed a baseline (1874 ADHD:LD+/-, 779 LD:ADHD+/-, 2338 ADHD a/o LD) or 24-48 h post-concussion (175 ADHD:LD+/-, 77 LD:ADHD+/-, 216 ADHD a/o LD) ImPACT assessment were included. Sensitivity and specificity were calculated using a normative data method and three machine learning classification methods: logistic regression, classification and regression tree, and random forest.

RESULTS

Using the four methods, participants with ADHD:LD+/- had sensitivities that ranged from 0.474 to 0.697, and specificities that ranged from 0.538 to 0.686. Participants with LD:ADHD+/- had sensitivities that ranged from 0.455 to 0.688, and specificities that ranged from 0.456 to 0.588. For participants with ADHD a/o LD, sensitivities ranged from 0.542 to 0.755, and specificities ranged from 0.451 to 0.724.

CONCLUSIONS

For all subgroups and analytical methods, the results illustrate sensitivity and specificity values below typically accepted levels indicative of clinical utility. These findings support that using ImPACT alone may be insufficient to inform concussion diagnoses and encourages the use of a multi-dimensional concussion assessment.

Recovery of symptoms, neurocognitive and vestibular-ocular-motor function and academic ability after sports-related concussion (SRC) in university-aged student-athletes: a systematic review

BACKGROUND

Physiological differences between a maturing and matured brain alters how Sports-Related Concussion (SRC) affects different age groups; therefore, a review specific to university-aged student-athletes is needed.

OBJECTIVES

Determine time to recovery for symptom burden, neurocognitive and Vestibular-Ocular-Motor (VOM) function and academic impact in university-aged student-athletes.

METHODS

Searches were conducted in PubMed, SpringerLink, PsycINFO, Science Direct, Scopus, Cochrane, Web of Science and EMBASE. Articles were included if they contained original data collected within 30 days in university-aged student-athletes, analysed SRC associated symptoms, neurocognitive or VOM function or academic ability and published in English. Two reviewers independently reviewed sources, using the Oxford Classification of Evidence-Based Medicine (CEBM) and the Downs and Black checklist, and independently extracting data before achieving consensus.

RESULTS

58 articles met the inclusion criteria. Recovery of symptoms occurred by 7 and 3-5.3 days for neurocognition. The evidence base did not allow for a conclusion on recovery time for VOM function or academic ability. Few papers investigated recovery times at specified re-assessment time-points and have used vastly differing methodologies.

CONCLUSIONS

To fully understand the implication of SRC on the university-aged student-athlete' studies using a multi-faceted approach at specific re-assessments time points are required.Systematic review registration number: CRD42019130685.

Determining Sport Concussion Assessment Tool fifth Edition (SCAT5) reliable change in male professional hockey players

OBJECTIVES

The purpose of this paper is to provide reliable change metrics and assess the test-retest psychometrics of the Sport Concussion Assessment Tool fifth Edition (SCAT5) in a multilingual sample of professional ice hockey players.

METHODS

The SCAT5 was administered to National Hockey League and American Hockey League male professional ice hockey players as part of the 2018 and 2019 season medical evaluations. We extracted data from an existing clinical database of players who were administered two consecutive baseline evaluations and had no intervening concussions to assess psychometric properties (eg, test-retest reliability) and develop reliable change metrics.

RESULTS

Overall, 1007 players met inclusion criteria. Players were reassessed on average 344.52 (±62.52) days following their first baseline. Test-retest reliability ranged from r=0.3 to r=0.5. Reliable change metrics for Immediate Memory varied considerably dependent on form order. Significant differences were found between English versus non-English language preference on Immediate Memory and Concentration but not Delayed Memory or the modified Balance Error Scoring System (mBESS). Reliable change indices at the 90% CI were: Symptom Severity (5), Total Symptoms (3), Immediate Memory (3-8), Concentration (2), mBESS (5) and Delayed Memory (2-4).

CONCLUSIONS

Our findings highlight the importance of considering form differences and language preference when determining reliable change from baseline on the SCAT5 in male professional hockey players. The relatively modest test-retest reliability of the measures leaves room for improved psychometric properties and increased sensitivity to concussion in future iterations of the SCAT.

Utility of VOMS, SCAT3, and ImPACT Baseline Evaluations for Acute Concussion Identification in Collegiate Athletes: Findings From the NCAA-DoD Concussion Assessment, Research and Education (CARE) Consortium

BACKGROUND

The Vestibular/Ocular-Motor Screening (VOMS) is a valuable component of acute (<72 hours) sports-related concussion (SRC) assessments and is increasingly used with the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) instrument and the third edition of the Sport Concussion Assessment Tool (SCAT3). Research has suggested that VOMS acute postinjury scores are useful in identifying acute concussion. However, the utility of preseason baseline measurements to improve diagnostic accuracy remains ambiguous. To this end, there is a need to determine how reliable VOMS baseline assessments are across years and whether incorporating individuals' baseline performance improves diagnostic yield for acute concussions.

PURPOSE

To analyze VOMS, SCAT3, and ImPACT to evaluate the test-retest reliability of consecutive-year preseason baseline assessments to directly compare the diagnostic utility of these tools when incorporating baseline assessments versus using postinjury data alone to identify acute SRC.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

Preseason and postinjury VOMS, SCAT3, ImPACT Post-Concussion Symptom Scale (PCSS), and ImPACT composite scores were analyzed for 3958 preseason (47.7% female) and 496 acute (≤48 hours) SRC (37.5% female) collegiate athlete evaluations in the National Collegiate Athletic Association-Department of Defense Concussion Assessment Research and Education Consortium. Descriptive statistics, Kolmogorov-Smirnov significance, and Cohen d effect size were calculated. Consecutive-year baseline reliability was evaluated for a subset of 447 athlete encounters using Pearson r, Cohen κ, Cohen d, and 2-way mixed intraclass correlation coefficients (ICCs). Wilcoxon signed rank tests were used to determine the statistical significance between population performances, and the 90% reliable change index (RCI) was calculated from the test-retest results. Preseason to postinjury change scores were then calculated from each tool's RCI. Finally, receiver operating characteristic (ROC) curve analyses were conducted, and DeLong method was used to compare the area under the curve (AUC) of raw postinjury scores versus change scores from preseason baseline assessments. Potential effects of sex, medical history (learning disorders or attention-deficit/hyperactivity disorder), and outlier data were also explored.

RESULTS

Effect sizes were large, and overall predictive utilities were clinically useful for postinjury VOMS Total (d = 2.44; AUC = 0.85), the SCAT3 Symptom Evaluation total severity score (d = 1.74; AUC = 0.82), and the ImPACT PCSS total severity score (d = 1.67; AUC = 0.80). Comparatively, effect sizes were small and predictive utilities were poor for Standardized Assessment of Concussion (SAC), modified Balance Error Scoring System (mBESS), and all ImPACT composites (d = 0.11-0.46; AUC = 0.48-0.59). Preseason baseline test-retest reliability was poor to moderate (r = 0.23-0.52; κ = 0.32-0.36; ICC = 0.36-0.68) for all assessments except ImPACT Visual Motion Sensitivity (r = 0.73; ICC = 0.85). Incorporating baseline scores for VOMS Total, SCAT3 (Symptom Evaluation, SAC, mBESS), ImPACT PCSS, or ImPACT composites did not significantly improve AUCs.

CONCLUSION

VOMS Total and symptom severity (SCAT3, PCSS) total scores had large effect sizes and clinically useful AUCs for identifying acute concussion. However, all tools demonstrated high within-patient test-retest variability, resulting in poor reliability. The findings in this sample of collegiate athletes suggest that incorporating baseline assessments does not significantly increase diagnostic yield for acute concussion.

Improved post-injury cognitive test results: examining invalid baseline ImPACT testing

OBJECTIVE

Evidence suggests that Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) validity thresholds may not be adequately sensitive to baseline performances that are not representative of an athlete's full, uninjured cognitive abilities. The true prevalence of this occurrence is unknown. This study used improvement on post-injury testing (i.e., better performance after the athlete has been removed from play due to suspected concussion than at baseline) to assess the frequency of unrepresentative baseline ImPACT assessments.

METHOD

Post-injury ImPACT assessments by NCAA athletes with preceding baseline performance that was considered valid using traditional indices were included. Published reliable change indices (RCI) identified acute post-injury composite scores that improved from baseline.

RESULTS

Of 155 post-injury assessments, 68 (43.9%) exhibited reliable improvement from baseline on at least 1 composite score, even after excluding persons with invalid protocols.

CONCLUSIONS

Prevalence of ImPACT unrepresentative baseline ImPACT performances may be higher than previously estimated, and many individuals may not be detected by current validity indices. Further research is needed to refine assessment and promote player safety.

A Neuropsychological Perspective on Defining Cognitive Impairment in the Clinical Study of Alzheimer’s Disease: Towards a More Continuous Approach

The global fight against Alzheimer’s disease (AD) poses unique challenges for the field of neuropsychology. Along with the increased focus on early detection of AD pathophysiology, characterizing the earliest clinical stage of the disease has become a priority. We believe this is an important time for neuropsychology to consider how our approach to the characterization of cognitive impairment can be improved to detect subtle cognitive changes during early-stage AD. The present article aims to provide a critical examination of how we define and measure cognitive status in the context of aging and AD. First, we discuss pitfalls of current methods for defining cognitive impairment within the context of research shifting to earlier (pre)symptomatic disease stages. Next, we introduce a shift towards a more continuous approach for identifying early markers of cognitive decline and characterizing progression and discuss how this may be facilitated by novel assessment approaches. Finally, we summarize potential implications and challenges of characterizing cognitive status using a continuous approach.

Annual Baseline King-Devick Oculomotor Function Testing Is Needed Due to Scores Varying by Age

Objective: To document baseline King-Devick (K-D) oculomotor function scores for male and female participants aged between 4 and 20 years old. Methods: Utilising a cross section of schools, rugby clubs and gymnastic clubs, 1936 participants (1300 male, 636 female) completed the spiral-bound K-D test for the identification of disturbed oculomotor function. Results: This study identified that overall, the baseline scores of the K-D test became faster by 1.4 (0.3 to 4.5) s per year, when compared with the previous age group in the same number of reading card groups. When comparing normative values of the original K-D validation study with the same age groups of the current cohort, participants aged 6 to 11 years recorded a faster baseline time (range 3.5 to 8.6 s), while those in the 12 to 14 years. age group recorded slower baseline times (range −3.9 to −7.9 s). Discussion: In general, there were age group differences, but not sex differences, for K-D test times in the current cohort. Analysis of single card times, across all age groups, showed changes likely due to improved reading time. Conclusion: The results support the need for individualised annual pre-injury baseline testing of the K-D test.

A much needed metric: Defining reliable and statistically meaningful change of the oral version Symbol Digit Modalities Test (SDMT)

BACKGROUND

The Symbol Digit Modalities Test (SDMT) has been recommended for use in clinical trials and outcome studies to monitor cognitive change. However, defining what is a meaningful change has been elusive for several years.

OBJECTIVE

The present investigation aimed to develop methods for assessing individual-level statistically significant change on the SDMT - reliable change indices (RCIs) and standardized regression-based (SRB) equations.

METHODS

A total of 219 healthy individuals completed the oral version SDMT at baseline, 6-month and 1-year follow-up.

RESULTS

The SDMT demonstrated high reliability across all time points (r's = 0.83 to 0.86). Reliable change scores of 7, 8, and 10 points for the 6-month intervals represented statistically meaningful change at the 0.70, 0.80, and 0.90 confidence intervals, respectively. Over 1-year, a difference of 8, 10, and 12 was statistically meaningful at the 0.70, 0.80, and 0.90 confidence intervals, respectively. SRB equations are also provided taking into account additional factors found to be predictive of SDMT scores over time.

CONCLUSION

Clinicians frequently denote a decline of 4 points on the SDMT as meaningful. Results in this large normative sample show that higher cut-points are needed to demonstrate statistically significant decline at the individual level. RCIs are provided for 6 month and one year assessment, which is typical in clinical practice and trials. SRB equations are also provided for use when applicable and may provide a more precise assessment of meaningful change.

Brain function associated with reaction time after sport-related concussion

Concussion is associated with significant functional disturbances in the first week post-injury. Computerized neurocognitive testing tools have become widely adopted in concussion management, to identify specific domains of impairment and obtain more objective measures of recovery. Reaction time (RT) slowing is a common sequela of concussion, however, the functional brain networks that underlie RT performance remain under-studied in both healthy and concussed athletic cohorts. This study used blood-oxygenation-level-dependent function magnetic resonance imaging (BOLD fMRI) to evaluate resting brain function of 45 university-level athletes with concussion in the first week post-injury, along with a control cohort of 102 athletes without recent concussion. We evaluated the main effects of concussion and RT on functional connectivity, along with concussion × RT interactions, using multivariate analysis techniques. Concussion was associated with reduced connectivity throughout the brain, whereas RT slowing was associated with elevated connectivity in parietal and temporal regions, for both control and concussed groups. For the concussed group, RT slowing was also associated with disrupted connectivity between fronto-insular and default mode networks. For concussed athletes, the brain networks associated with slower post-injury RT also showed similar but non-significant associations with longitudinal changes in RT performance relative to pre-injury baseline. These study findings provide new insights into the effects of concussion on neurocognitive function and suggest the presence of functional brain networks that are specific to concussion-related RT slowing.

A cross-sectional cohort study of post-concussive symptoms and their relationships with depressive symptoms in youth with and without concussion

OBJECTIVES

To evaluate the frequency and severity of post-concussive symptoms in youth with a history of concussion relative to youth without concussion who had another medical diagnosis, as well as compare the correlations between post-concussive and depressive symptoms between groups. We hypothesized comparable symptom reporting and correlations in each group.

METHODS

A total of 564 youth ages 8-18 years were assessed regarding post-concussive symptoms. A subset of youth (n = 360) were compared on correlations between post-concussive and depressive symptoms. Non-parametric statistics were used for most analyses.

RESULTS

Youth with concussion reported a comparable number of post-concussive and depressive symptoms as youth with another medical condition without concussion. However, those with concussion reported greater post-concussive symptom severity (but small effect sizes). Relationships between post-concussive and depressive symptoms were comparable for both groups, but for those who sustained a concussion, the correlation was significantly stronger for females than males.

CONCLUSIONS

This study further demonstrates that post-concussive symptoms are nonspecific and provide little functional utility. Post-concussive and depressive symptoms are strongly correlated, particularly in females with concussion. Psychiatric comorbidities and other medical diagnoses should be assessed pre-injury because both affect interpretation of post-concussive symptom reports.

A Novel Neuropsychological Tool for Immersive Assessment of Concussion and Correlation with Subclinical Head Impacts

Mild traumatic brain injury (mTBI) remains a diagnostic challenge and therefore strategies for objective assessment of neurological function are key to limiting long-term sequelae. Current assessment methods are not optimal in austere environments such as athletic fields; therefore, we developed an immersive tool, the Display Enhanced Testing for Cognitive Impairment and mTBI (DETECT) platform, for rapid objective neuropsychological (NP) testing. The objectives of this study were to assess the ability of DETECT to accurately identify neurocognitive deficits associated with concussion and evaluate the relationship between neurocognitive measures and subconcussive head impacts. DETECT was used over a single season of two high school and two college football teams. Study participants were instrumented with Riddell Head Impact Telemetry (HIT) sensors and a subset tested with DETECT immediately after confirmed impacts for different combinations of linear and rotational acceleration. A total of 123 athletes were enrolled and completed baseline testing. Twenty-one players were pulled from play for suspected concussion and tested with DETECT. DETECT was 86.7% sensitive (95% confidence interval [CI]: 59.5%, 98.3%) and 66.7% specific (95% CI: 22.3%, 95.7%) in correctly identifying athletes with concussions (15 of 21). Weak but significant correlations were found between complex choice response time (processing speed and divided attention) and both linear (Spearman rank correlation coefficient 0.262, p = 0.02) and rotational (Spearman coefficient 0.254, p = 0.03) acceleration on a subset of 76 players (113 DETECT tests) with no concussion symptoms. This study demonstrates that DETECT confers moderate to high sensitivity in identifying acute cognitive impairment and suggests that football impacts that do not result in concussion may negatively affect cognitive performance immediately following an impact. Specificity, however, was not optimal and points to the need for additional studies across multiple neurological domains. Given the need for more objective concussion screening in triage situations, DETECT may provide a solution for mTBI assessment.

Insular Connectivity Is Associated With Self-Appraisal of Cognitive Function After a Concussion

Concussion is associated with acute cognitive impairments, with declines in processing speed and reaction time being common. In the clinical setting, these issues are identified via symptom assessments and neurocognitive test (NCT) batteries. Practice guidelines recommend integrating both symptoms and NCTs into clinical decision-making, but correlations between these measures are often poor. This suggests that many patients experience difficulties in the self-appraisal of cognitive issues. It is presently unclear what neural mechanisms give rise to appraisal mismatch after a concussion. One promising target is the insula, which regulates aspects of cognition, particularly interoception and self-monitoring. The present study tested the hypothesis that appraisal mismatch is due to altered functional connectivity of the insula to frontal and midline structures, with hypo-connectivity leading to under-reporting of cognitive issues and hyper-connectivity leading to over-reporting. Data were collected from 59 acutely concussed individuals and 136 normative controls, including symptom assessments, NCTs and magnetic resonance imaging (MRI) data. Analysis of resting-state functional MRI supported the hypothesis, identifying insular networks that were associated with appraisal mismatch in concussed athletes that included frontal, sensorimotor, and cingulate connections. Subsequent analysis of diffusion tensor imaging also determined that symptom over-reporting was associated with reduced fractional anisotropy and increased mean diffusivity of posterior white matter. These findings provide new insights into the mechanisms of cognitive appraisal mismatch after a concussion. They are of particular interest given the central role of symptom assessments in the diagnosis and clinical management of concussion.

Developing Insights for Possible and Probable Acute Concussions Using Cluster Analysis

Few studies have analyzed the Sport Concussion Assessment Tool's (SCAT) utility among athletes whose concussion assessment is challenging. Using a previously published algorithm, we identified possible and probable concussions at <6 h (n = 393 males, n = 265 females) and 24-48 h (n = 323 males, n = 236 females) post-injury within collegiate student-athletes and cadets from the Concussion Assessment, Research, and Education (CARE) Consortium. We applied cluster analysis to characterize performance on the Standard Assessment of Concussion (SAC), Balance Error Scoring System (BESS), and the SCAT symptom checklist for these athletes. Among the cluster sets that best separated acute concussions and normal performances, total symptom number raw score and change and post-traumatic migraine raw score and change score were the most frequent clustering variables across males and females at <6 h and 24-48 h. Similarly, total symptom number raw score and change score and post-traumatic migraine raw score and change score were most significantly different between clusters for males and females at <6 h and 24-48 h. Our results suggest that clinicians should focus on total symptom number, post-traumatic migraine symptoms, and cognitive-fatigue symptoms when assessing possible and probable concussions, followed by the SAC and BESS scores.

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.

Optimizing Components of the Sport Concussion Assessment Tool for Acute Concussion Assessment

BACKGROUND

The Sport Concussion Assessment Tool (SCAT) could be improved by identifying critical subsets that maximize diagnostic accuracy and eliminate low information elements.

OBJECTIVE

To identify optimal SCAT subsets for acute concussion assessment.

METHODS

Using Concussion Assessment, Research, and Education (CARE) Consortium data, we compared student-athletes' and cadets' preinjury baselines (n = 2178) with postinjury assessments within 6 h (n = 1456) and 24 to 48 h (n = 2394) by considering demographics, symptoms, Standard Assessment of Concussion (SAC), and Balance Error Scoring System (BESS) scores. We divided data into training/testing (60%/40%) sets. Using training data, we integrated logistic regression with an engineering methodology-mixed integer programming-to optimize models with ≤4, 8, 12, and 16 variables (Opt-k). We also created models including only raw scores (Opt-RS-k) and symptom, SAC, and BESS composite scores (summary scores). We evaluated models using testing data.

RESULTS

At <6 h and 24 to 48 h, most Opt-k and Opt-RS-k models included the following symptoms: do not feel right, headache, dizziness, sensitivity to noise, and whether physical or mental activity worsens symptoms. Opt-k models included SAC concentration and delayed recall change scores. Opt-k models had lower Brier scores (BS) and greater area under the curve (AUC) (<6 h: BS = 0.072-0.089, AUC = 0.95-0.96; 24-48 h: BS = 0.085-0.093, AUC = 0.94-0.95) than Opt-RS-k (<6 h: BS = 0.082-0.087, AUC = 0.93-0.95; 24-48 h: BS = 0.095-0.099, AUC = 0.92-0.93) and summary score models (<6 h: BS = 0.14, AUC = 0.89; 24-48 h: BS = 0.15, AUC = 0.87).

CONCLUSION

We identified SCAT subsets that accurately assess acute concussion and improve administration time over the complete battery, highlighting the importance of eliminating "noisy" elements. These findings can direct clinicians to the SCAT components that are most sensitive to acute concussion.

Validation of a Machine Learning Brain Electrical Activity-Based Index to Aid in Diagnosing Concussion Among Athletes

IMPORTANCE

An objective, reliable indicator of the presence and severity of concussive brain injury and of the readiness for the return to activity has the potential to reduce concussion-related disability.

OBJECTIVE

To validate the classification accuracy of a previously derived, machine learning, multimodal, brain electrical activity-based Concussion Index in an independent cohort of athletes with concussion.

DESIGN, SETTING, AND PARTICIPANTS

This prospective diagnostic cohort study was conducted at 10 clinical sites (ie, US universities and high schools) between February 4, 2017, and March 20, 2019. A cohort comprising a consecutive sample of 207 athletes aged 13 to 25 years with concussion and 373 matched athlete controls without concussion were assessed with electroencephalography, cognitive testing, and symptom inventories within 72 hours of injury, at return to play, and 45 days after return to play. Variables from the multimodal assessment were used to generate a Concussion Index at each time point. Athletes with concussion had experienced a witnessed head impact, were removed from play for 5 days or more, and had an initial Glasgow Coma Scale score of 13 to 15. Participants were excluded for known neurologic disease or history within the last year of traumatic brain injury. Athlete controls were matched to athletes with concussion for age, sex, and type of sport played.

MAIN OUTCOMES AND MEASURES

Classification accuracy of the Concussion Index at time of injury using a prespecified cutoff of 70 or less (total range, 0-100, where ≤70 indicates it is likely the individual has a concussion and >70 indicates it is likely the individual does not have a concussion).

RESULTS

Of 580 eligible participants with analyzable data, 207 had concussion (124 male participants [59.9%]; mean [SD] age, 19.4 [2.5] years), and 373 were athlete controls (187 male participants [50.1%]; mean [SD] age, 19.6 [2.2] years). The Concussion Index had a sensitivity of 86.0% (95% CI, 80.5%-90.4%), specificity of 70.8% (95% CI, 65.9%-75.4%), negative predictive value of 90.1% (95% CI, 86.1%-93.3%), positive predictive value of 62.0% (95% CI, 56.1%-67.7%), and area under receiver operator characteristic curve of 0.89. At day 0, the mean (SD) Concussion Index among athletes with concussion was significantly lower than among athletes without concussion (75.0 [14.0] vs 32.7 [27.2]; P < .001). Among athletes with concussion, there was a significant increase in the Concussion Index between day 0 and return to play, with a mean (SD) paired difference between these time points of -41.2 (27.0) (P < .001).

CONCLUSIONS AND RELEVANCE

These results suggest that the multimodal brain activity-based Concussion Index has high classification accuracy for identification of the likelihood of concussion at time of injury and may be associated with the return to control values at the time of recovery. The Concussion Index has the potential to aid in the clinical diagnosis of concussion and in the assessment of athletes' readiness to return to play.

A quick assessment of reliable change in fatigue: Reliable change indices of the modified fatigue impact scale - 5 item (MFIS-5)

BACKGROUND

Reliably monitoring changes in fatigue is an ongoing concern.

OBJECTIVE

Evaluate reliable change using the Modified Fatigue Impact Scale 5-item version (MFIS-5) in people with MS (PwMS).

METHODS

The MFIS-5 was administered at three time points in 157 PwMS. Test-retest reliability and reliable change scores were calculated at the 0.70, 0.80, 0.90, and 0.95 confidence intervals.

RESULTS

Difference scores of 3, 4, 5, and 6 represent statistically meaningful change at the 0.70, 0.80, 0.90, and 0.95 confidence intervals, respectively.

CONCLUSION

Cut points derived from this study and prior work can help reliably assess changes in fatigue over time.

Sensitivity and Specificity of Computer-Based Neurocognitive Tests in Sport-Related Concussion: Findings from the NCAA-DoD CARE Consortium

BACKGROUND

To optimally care for concussed individuals, a multi-dimensional approach is critical and a key component of this assessment in the athletic environment is computer-based neurocognitive testing. However, there continues to be concerns about the reliability and validity of these testing tools. The purpose of this study was to determine the sensitivity and specificity of three common computer-based neurocognitive tests (Immediate Post-Concussion Assessment and Cognitive Testing [ImPACT], CNS Vital Signs, and CogState Computerized Assessment Tool [CCAT]), to provide guidance on their clinical utility.

METHODS

This study analyzed assessments from a cohort of collegiate athletes and non-varsity cadets from the NCAA-DoD CARE Consortium. The data were collected from 2014-2018. Study participants were divided into two testing groups [concussed, n = 1414 (baseline/24-48 h) and healthy, n = 8305 (baseline/baseline)]. For each test type, change scores were calculated for the components of interest. Then, the Normative Change method, which used normative data published in a similar cohort, and the Reliable Change Index (RCI) method were used to determine if the change scores were significant.

RESULTS

Using the Normative Change method, ImPACT performed best with an 87.5%-confidence interval and 1 number of components failed (NCF; sensitivity = 0.583, specificity = 0.625, F1 = 0.308). CNS Vital Signs performed best with a 90%-confidence interval and 1 NCF (sensitivity = 0.587, specificity = 0.532, F1 = 0.314). CCAT performed best when using a 75%-confidence interval and 2 NCF (sensitivity = 0.513, specificity = 0.715, F1 = 0.290). When using the RCI method, ImPACT performed best with an 87.5%-confidence interval and 1 NCF (sensitivity = 0.626, specificity = 0.559, F1 = 0.297).

CONCLUSION

When considering all three computer-based neurocognitive tests, the overall low sensitivity and specificity results provide additional evidence for the use of a multi-dimensional assessment for concussion diagnosis, including symptom evaluation, postural control assessment, neuropsychological status, and other functional assessments.

Clinical Reaction-Time Performance Factors in Healthy Collegiate Athletes

CONTEXT

In the absence of baseline testing, normative data may be used to interpret postconcussion scores on the clinical reaction-time test (RTclin). However, to provide normative data, we must understand the performance factors associated with baseline testing.

OBJECTIVE

To explore performance factors associated with baseline RTclin from among candidate variables representing demographics, medical and concussion history, self-reported symptoms, sleep, and sport-related features.

DESIGN

Cross-sectional study.

SETTING

Clinical setting (eg, athletic training room).

PATIENTS OR OTHER PARTICIPANTS

A total of 2584 National Collegiate Athletic Association student-athletes (n = 1206 females [47%], 1377 males [53%], and 1 unreported (<0.1%); mass = 76.7 ± 18.7 kg; height = 176.7 ± 11.3 cm; age = 19.0 ± 1.3 years) from 3 institutions participated in this study as part of the Concussion Assessment, Research and Education Consortium.

MAIN OUTCOME MEASURE(S)

Potential performance factors were sex; race; ethnicity; dominant hand; sport type; number of prior concussions; presence of anxiety, learning disability, attention-deficit disorder or attention-deficit/hyperactivity disorder, depression, or migraine headache; self-reported sleep the night before the test; mass; height; age; total number of symptoms; and total symptom burden at baseline. The primary study outcome measure was mean baseline RTclin.

RESULTS

The overall RTclin was 202.0 ± 25.0 milliseconds. Female sex (parameter estimate [B] = 8.6 milliseconds, P < .001, Cohen d = 0.54 relative to male sex), black or African American race (B = 5.3 milliseconds, P = .001, Cohen d = 0.08 relative to white race), and limited-contact (B = 4.2 milliseconds, P < .001, Cohen d = 0.30 relative to contact) or noncontact (B = 5.9 milliseconds, P < .001, Cohen d = 0.38 relative to contact) sport participation were associated with slower RTclin. Being taller was associated with a faster RTclin, although this association was weak (B = -0.7 milliseconds, P < .001). No other predictors were significant. When adjustments are made for sex and sport type, the following normative data may be considered (mean ± standard deviation): female, noncontact (211.5 ± 25.8 milliseconds), limited contact (212.1 ± 24.3 milliseconds), contact (203.7 ± 21.5 milliseconds); male, noncontact (199.4 ± 26.7 milliseconds), limited contact (196.3 ± 23.9 milliseconds), contact (195.0 ± 23.8 milliseconds).

CONCLUSIONS

Potentially clinically relevant differences existed in RTclin for sex and sport type. These results provide normative data adjusting for these performance factors.

Assessing the Long-Term Impact of Concussion upon Cognition: A 5-Year Prospective Investigation

OBJECTIVE

Jockeys have high rates of concussion, with 5% of jockeys receiving at least one concussion annually. The impact of acute concussion upon cognition is well understood, but less is known about the long-term effects of concussion upon cognition. Our aim was to assess the impact of concussion upon jockeys who had provided pre-concussion assessments of cognition using a prospective design.

METHOD

In this study, over a 5-year period, we assessed the cognitive performance of jockeys with ≥1 medically diagnosed concussion (MDC; n = 17, months since concussion, M = 29.18), against those who had not been concussed (NC; n = 41). Jockeys who had not been concussed in the preceding 6 months completed four computer-based cognitive assessments from the CogSport battery.

RESULTS

Unlike the majority of the small existing literature, there was no difference (p ≥ .05) between the MDC and NC groups after controlling for age and baseline performance. Additionally, we used a measure of reliable change to assess for clinically meaningful decrements from baseline in each test and composite score 5 years later. None of the jockeys in the MDC group recorded significant decrements on any CogSport measure from baseline (z > -1.65).

CONCLUSIONS

The findings suggest that the presence of concussion does not result in persistent decrements in cognitive performance and that when findings are considered collectively, assessing factors beyond medically diagnosed concussion (e.g., chronic stress, undiagnosed concussion) may improve the interpretation of our current findings.

CDC Guideline on Mild Traumatic Brain Injury in Children: Important Practice Takeaways for Sports Medicine Providers

OBJECTIVES

The Centers for Disease Control and Prevention (CDC) published an evidence-based guideline on the diagnosis and management of pediatric mild traumatic brain injury (mTBI) in 2018. This commentary provides key practice takeaways for sports medicine providers outlined in the Guideline recommendations.

DATA SOURCES

The CDC Pediatric mTBI Guideline was developed through a rigorous scientific process using a modified Grading of Recommendations, Assessment, Development and Evaluations (GRADE) methodology. A systematic review of the scientific literature published over a 25-year period for all causes of pediatric mTBI formed the basis of the Guideline.

MAIN RESULTS

The key practice takeaways for sports medicine providers focus on preseason evaluations, neuroimaging, symptom-based assessment, managing recovery, monitoring for persistent symptoms, and return to activity, including sport and school.

CONCLUSIONS

Sports medicine providers play an integral part in the implementation of evidence-based practices that promote appropriate diagnosis and management of mTBI in children. This commentary highlights key practice takeaways that sports medicine providers can implement.

A Cohort Study of the Temporal Stability of ImPACT Scores Among NCAA Division I Collegiate Athletes: Clinical Implications of Test-Retest Reliability for Enhancing Student Athlete Safety

OBJECTIVE

In this study we examined the temporal stability of the Immediate Post-Concussion Assessment and Cognitive Test (ImPACT) within NCAA Division I athletes across various timepoints using an exhaustive series of statistical models.

METHODS

Within a cohort design, 48 athletes completed repeated baseline ImPACT assessments at various timepoints. Intraclass correlation coefficients (ICC) were calculated using a two-way mixed effects model with absolute agreement.

RESULTS

Four ImPACT composite scores (Verbal Memory, Visual Memory, Visual Motor Speed, and Reaction Time) demonstrated moderate reliability (ICC = 0.51-0.66) across the span of a typical Division I athlete's career, which is below previous reliability recommendations (0.90) for measures used in individual decision-making. No evidence of fixed bias was detected within Verbal Memory, Visual Motor Speed, or Reaction Time composite scores, and minimal detectable change values exceeded the limits of agreement.

CONCLUSIONS

The demonstrated temporal stability of the ImPACT falls below the published recommendations, and as such, fails to provide robust support for the NCAA's recommendation to obtain a single preparticipation cognitive baseline for use in sports-related concussion management throughout an athlete's career. Clinical interpretation guidelines are provided for clinicians who utilize baseline ImPACT scores for later performance comparisons.

Institutionally Based ImPACT Test® Normative Values May Differ from Manufacturer-Provided Normative Values

OBJECTIVE

The necessity for pre-injury baseline computerized neurocognitive assessments versus comparing post-concussion outcomes to manufacturer-provided normative data is unclear. Manufacturer-provided norms may not be equivalent to institution-specific norms, which poses risks for misclassifying the presence of impairment when comparing individual post-concussion performance to manufacturer-provided norms. The objective of this cohort study was to compare institutionally derived normative data to manufacturer-provided normative values provided by ImPACT® Applications, Incorporated.

METHOD

National Collegiate Athletic Association Division 1 university student athletes (n = 952; aged 19.2 ± 1.4 years, 42.5% female) from one university participated in this study by completing pre-injury baseline Immediate Post-Concussion Assessment and Cognitive Test (ImPACT) assessments. Participants were separated into 4 groups based on ImPACT's age and gender norms: males <18 years old (n = 186), females <18 years old (n = 165), males >19 years old (n = 361) or females >19 years old (n = 240). Comparisons were made between manufacturer-provided norms and institutionally derived normative data for each of ImPACT's clinical composite scores: Verbal (VEM) and Visual (VIM) Memory, Visual Motor Speed (VMS), and Reaction Time (RT). Outcome scores were compared for all groups using a Chi-squared goodness of fit analysis.

RESULTS

Institutionally derived normative data indicated above average performance for VEM, VIM, and VMS, and slightly below average performance for RT compared to the manufacturer-provided data (χ2 ≥ 20.867; p < 0.001).

CONCLUSIONS

Differences between manufacturer- and institution-based normative value distributions were observed. This has implications for an increased risk of misclassifying impairment following a concussion in lieu of comparison to baseline assessment and therefore supports the need to utilize baseline testing when feasible, or otherwise compare to institutionally derived norms rather than manufacturer-provided norms.

Using Variance to Explore the Diagnostic Utility of Baseline Concussion Testing

The Graded Symptom Checklist (GSC), Standardized Assessment of Concussion (SAC), Balance Error Scoring System (BESS), and King-Devick Test (KDT) are considered important components of concussion assessment. Whether baseline testing improves the diagnostic utility of these tests remains unclear. We performed an observational cohort study to investigate the within-subject and between-subjects variability of these tests over repeated assessments during two football seasons to examine whether baseline testing reduces variability in test performance. Thirty-five male collegiate football players completed weekly clinical concussion assessments over two seasons. Within-subject (week-to-week) and between-subjects (player-to-player) variability for each test were compared using a bootstrap analysis. Within-subject and between-subjects proportions of overall variance for each test score were calculated. Mixed-model analyses were used to quantify practice effects resulting from repeated testing. For the GSC and BESS, within-subject and between-subjects variability did not significantly differ. For the KDT, the proportion of within-subject variance (20.2%) was significantly less than the between-subjects variance (79.8%). For SAC, however, the proportion of within-subject variance (66.8%) was significantly greater than the between-subjects variance (33.8%). A small, but significant, practice effect was observed for the BESS and KDT tests. When athletes are evaluated during a football season for concussion using the GSC, SAC, and BESS, comparing their scores to baseline performance is likely no more beneficial than comparing them to normative population data for identifying neurological changes associated with concussion. For the KDT, comparison to baseline testing is likely beneficial because of significantly higher between-subjects variability.

Normal variability within a collegiate athlete sample: A rationale for comprehensive baseline testing

OBJECTIVE

Sport-related concussions continue to garner attention as research emerges about the effects of these injuries. Many have advocated for cognitive baselines; however, there is no uniform practice of neuropsychological baseline testing at the collegiate level leading to variance in administration and interpretation. Continuing clarification on best practices is essential for the field, especially considering previous research highlighting normal variability on cognitive tests in other populations, but also the need for separate normative sources for those with attention and learning problems. This study aimed to evaluate the range of normal variability in a diverse sample of collegiate athletes administered a traditional neuropsychological baseline.

METHOD

Neuropsychological baseline measures were collected on 236 Division 1 University student athletes over 4 years. Frequency of scores that fell at 1, 1.5, and 2 or greater standard deviations were reviewed. Student athletes were further evaluated for likelihood of factors which could impact results (i.e. Attention-Deficit/Hyperactivity Disorder [ADHD], Specific Learning Disorder [SLD], and psychiatric distress).

RESULTS

The results demonstrated high rates of variability in most test scores for the collective sample. Student athletes at risk for ADHD, SLD, and/or psychiatric distress appeared to demonstrate a higher degree of variability relative to individuals with minimal risk.

CONCLUSION

Baseline evaluation data revealed the presence of normal variability in a student athlete population. Left unrecognized, this can lead to errors in clinical recommendations given the nature of concussion. Certain individuals have risk factors which may increase the range of variability, and this should be explored further in future research.

The Effect of Traumatic Brain Injury (TBI) on Cognitive Performance in a Sample of Active Duty U.S. Military Service Members

Introduction

Traumatic brain injury (TBI) is considered a signature injury from the fighting in Iraq and Afghanistan. Since the year 2000, over 370,000 U.S. active duty service members have been diagnosed with TBI. Although prior research has shown that even mild forms of TBI are associated with impaired cognitive performance, it is not clear which facets of cognition (computation, memory, reasoning, etc.) are impacted by injury.

Method

In the present study, we compared active duty military volunteers (n = 88) with and without TBI on six measures of cognition using the Automated Neuropsychological Assessment Metric software.

Results

Healthy volunteers exhibited significantly faster response times on the matching-to-sample, mathematical processing, and second round of simple reaction time tasks and had higher throughput scores on the mathematical processing and the second round of the simple reaction time tasks (P &lt; 0.05).

Conclusion

In this population, cognitive impairments associated with TBI influenced performance requiring working memory and basic neural processing (speed/efficiency).

ImPACT Normative Data of Ethnically Diverse Adolescent Athletes

OBJECTIVE

The aim of this research was to develop preliminary norms for the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) administered to a large sample of adolescent athletes from diverse ethnic backgrounds.

DESIGN

A retrospective records review.

SETTING

Middle and high school athletic departments.

PARTICIPANTS

A total of 5741 male and female adolescent athletes in Hawaii, aged 13 to 18 years, in grades 9 to 12 were included in the study.

INDEPENDENT VARIABLES

Age, sex, ethnicity, and sport.

MAIN OUTCOME MEASURES

ImPACT Composite scores (Verbal Memory, Visual Memory, Visual Motor Speed, Reaction Time, and Impulse Control) and Total Symptom score from baseline testing.

RESULTS

The results indicated statistically significant differences between age and sex groups, as well as between ethnic and sport groups.

CONCLUSIONS

The findings support the continued use of stratified norms for age and sex for ethnically diverse adolescent athletes. Comparisons of ethnic and sport groups deserve further investigation. When baseline scores are not available for postconcussion comparison, present observations tentatively support the cautious use of standard ImPACT norms with ethnically diverse athletes.

Invalid Baseline Testing with ImPACT: Does Sandbagging Occur with High School Athletes?

The aim of this large-scale research was to determine the frequency of valid, invalid, and sandbagging results in ImPACT baseline testing of high school athletes. This retrospective study identified valid, invalid (identified by five embedded Invalidity Indicators), and sandbagging (identified by three "red flags") results in the ImPACT baseline test scores of 6,346 high school athletes. In addition, the ImPACT postconcussion scores of 266 athletes who sustained a concussion during the school year were evaluated to compare the baseline-to-postconcussion changes of valid versus a combined group of invalid and sandbagging scorers. There were 3,299 (51.99%) athletes who had valid baseline scores, 269 (4.24%) had invalid scores, and 3,009 (47.42%) had sandbagging scores. (There were 231 who obtained both invalidity and sandbagging scores.) The overall difference in baseline-to-postconcussion changes between the valid scorers and the combined group of invalid and sandbagging scorers was statistically significant. The high rate of athletes who had invalid and sandbagging scores raised concern that the underperformance of baseline testing occurs more commonly than is probably realized by those who utilize computerized neuropsychological testing with high school athletes. Accordingly, efforts are needed to improve test administration procedures so that maximal attention and effort can be maintained among the test takers. In the meantime, increased caution is called for in employing the baseline-to-postconcussion paradigm when return-to-play decisions are made.

Neurocognitive Performance of 425 Top-Level Football Players: Sport-specific Norm Values and Implications

OBJECTIVE

Concussion diagnosis and management in sports largely relies on neurocognitive testing. In the absence of baseline assessment, only norm values of the general population are available for comparison with scores of concussed athletes. To evaluate whether (elite) sport specific norm values are needed, cognitive performance was compared between top-level football players and the general population.

METHODS

Cognitive performance of 425 top-level football players was evaluated using the computerized test battery CNS Vital Signs. Players were split into two age groups (15-19 and 20-29 years) and test results were compared with a norm sample (n = 268) by means of age-standardized scores using Cohen's d effect size statistics.

RESULTS

The younger age group outperformed the norm sample in all domains, with small to moderate effects on tests of processing speed (d = 0.58, 95% CI = 0.31,0.85), cognitive flexibility (d = 0.27, 95% CI = 0.01,0.53) and psychomotor speed (d = 0.97, 95% CI = 0.69,1.24). In the older age group, no differences were found on four out of six domains; a moderate positive effect was found for psychomotor speed (d = 0.74, 95% CI = 0.54,0.93), a small negative effect for reaction time (d = -0.47, 95% CI = -0.66,-0.28). Relative to the norm, older football players scored lower than younger football players on all test domains.

CONCLUSION

Cognitive performance of elite football players may be different from the general population. It is recommended to use football-specific norm scores for comparison with test results of concussed players, and to choose an adequate control group when investigating effects of contact sport on cognition. Studies with older/retired football players are needed to further analyze potential sport-specific age effects.

Sensitivity of the Cogstate Test Battery for Detecting Prolonged Cognitive Alterations Stemming From Sport-Related Concussions

OBJECTIVE

To determine if the Cogstate test battery contains the requisite sensitivity to detect prolonged cognitive alterations.

METHODS

One hundred twenty collegiate athletes (71 with a history of concussion; 49 controls) completed the Cogstate test battery, to which we added a 2-back condition. In addition to the Cogstate clinical (transformed variables), we analyzed the raw data.

RESULTS

The clinical variables failed to reveal any group differences. Further, although the raw data failed to reveal group differences for tasks measuring lower-level cognition, group differences were observed for accuracy on the 1- and 2-back tasks, which require multiple aspects of higher cognition. The overall classification accuracy was higher using the raw data than the clinical variables. The combined sensitivity of the 1- and 2-back task was moderate and specificity was high.

CONCLUSIONS

These results suggest that using the raw scores over clinical variables increases the sensitivity of the test battery. Moreover, these results add another piece of evidence suggesting that concussive injuries are associated with subtle long-term alterations in aspects of higher cognition. Importantly, these deficits would have gone unobserved if we had relied solely on automated clinical variables. The current results further our scientific understanding of concussion and may be used to advance clinical practices.

Using concurrent gait and cognitive assessments to identify impairments after concussion: a narrative review

Understanding how a concussion affects an individual is oftentimes difficult for clinicians due to the varying symptom profiles reported by the patient and the multifaceted and heterogeneous nature of the injury. Accordingly, the interpretation of postconcussion performance can be challenging, because many different testing paradigms have been reported as potentially useful in the literature. Among the types of tests clinicians use to understand how concussion affects an individual, both gait and neurocognitive evaluations have demonstrated utility. Our purpose is to describe how combined gait and cognitive (i.e., dual task), as well as single-task gait and computerized neurocognitive examinations can assist clinical decision-making.

Comparison of baseline ImPACT performance in amateur motocross riders to football and basketball athletes

PRIMARY OBJECTIVE

The American Motorcyclist Association requires professional riders to undergo baseline computerized neurocognitive testing (CNT) using the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) test for concussion management. It is recommended this practice be expanded to the amateur level, but limited research has explored whether baseline testing is necessary for youth when normative data is available. This study evaluates the utility of baseline testing for amateur riders by comparing their performance to those of traditional youth sports comprising normative datasets.

DESIGN/METHODS

An cross-sectional study comparing amateur motocross (N = 100) riders matched by age and sex to football (N = 100) and basketball (N = 100) athletes performance on baseline ImPACT testing.

RESULTS

ANCOVAs revealed a significant medium effect of group on measures of visual motor speed (F = 11.25, p < 0.001) and reaction time (F = 13.61, p < 0.001). Post hoc analyses revealed that motocross riders were significantly slower compared to football and basketball athletes. There were no significant differences (p > .05) between sport on measures of memory or symptoms.

CONCLUSIONS

Youth motocross riders performed significantly slower on speed measures compared to football and basketball athletes, providing preliminary support for the expansion of baseline ImPACT testing to the amateur level.

Descriptive Values for Dancers on Baseline Concussion Tools

CONTEXT

  Capturing baseline data before a concussion can be a valuable tool in individualized care. However, not all athletes, including dancers, have access to baseline testing. When baseline examinations were not performed, clinicians consult normative values. Dancers are unique athletes; therefore, describing values specific to dancers may assist those working with these athletes in making more informed decisions.

OBJECTIVE

  To describe values for key concussion measures of dancers. Our secondary aim was to examine whether differences existed between sexes and professional status. Finally, we explored factors that may affect dancers' scores.

DESIGN

  Cross-sectional study.

SETTING

  Professional dance companies and a collegiate dance conservatory.

PATIENTS OR OTHER PARTICIPANTS

  A total of 238 dancers (university = 153, professional = 85; women = 171; men = 67; age = 21.1 ± 4.8 years).

MAIN OUTCOME MEASURE(S)

  We calculated the total symptom severity from the Sport Concussion Assessment Tool-3rd edition; the Standardized Assessment of Concussion score; the modified Balance Error Scoring System score; and the King-Devick score for each participant. Group differences were analyzed with Mann-Whitney or t tests, depending on the data distribution. We used bivariate correlations to explore the effects of other potential influencing factors.

RESULTS

  Participants demonstrated the following baseline outcomes: symptom severity = 16.6 ± 12.8; Standardized Assessment of Concussion = 27.5 ± 1.8; modified Balance Error Scoring System = 3.2 ± 3.1 errors; and King-Devick = 41.5 ± 8.2 seconds. A Mann-Whitney test revealed differences in King-Devick scores between female (40.8 ± 8.0 seconds) and male (43.4 ± 8.4 seconds) dancers ( P = .04). An independent-samples t test also demonstrated a difference in modified Balance Error Scoring System scores between female (2.95 ± 3.1 errors) and male (3.8 ± 3.1 errors) dancers ( P = .02). Age, hours of sleep, height, and history of concussion, depression, or injury did not display moderate or strong associations with any of the outcome measures.

CONCLUSIONS

  Dancers' symptom severity scores appeared to be higher than the values reported for other athletes. Additional studies are needed to establish normative values and develop a model for predicting baseline scores.

Neuropsychological Screening of Sport-Related Concussion

Neuropsychological assessment is a key component of the multidimensional approach recommended by international consensus guidelines for evaluation of athletes affected by sport-related concussion (SRC). Over the past 2 decades, a number of conventional and computerized neuropsychological test batteries have been developed for the assessment of SRC. Standardized neurocognitive assessment tools are now commonly used across the continuum of concussion care, ranging from the sports sideline to critical care setting and the outpatient concussion clinic. We provide a brief, high-level overview of current approaches to best practice in neuropsychological assessment of SRC.