Assessing Brain Processing Deficits Using Neuropsychological and Vision-Specific Tests for Concussion

INTRODUCTION

Since verbal memory and visual processing transpire within analogous cerebral regions, this study assessed (i) if a visual function can predict verbal memory performance. It also hypothesized whether neurocognitive (e.g., ImPACT) tests focusing on the Visual Memory and Cognitive Efficacy Index will predict Verbal Memory scores and (ii) if vision metrics and age can identify individuals with a history of concussion. Finally, it also hypothesized that King-Devick and near point of convergence scores alongside age considerations will identify candidates with a prior reported history of concussion.

MATERIALS AND METHODS

This observational cohort assessed 25 collegiate ice hockey players prior to the competitive season considering age (19.76 ± 1.42 years) and BMI (25.9 ± 3.0 kg/cm2). Hypothesis 1 was assessed using a hierarchical (sequential) multiple regression analysis, assessing the predictive capacity of Visual Memory and Cognitive Efficacy Index scores in relation to Verbal Memory scores. Hypothesis 2 utilized a binomial logistic regression to determine if King-Devick and near point of convergence scores predict those with a prior history of concussion.

RESULTS

Hypothesis 1 developed two models, where Model 1 included Visual Memory as the predictor, while Model 2 added the Cognitive Efficacy Index as a predictor for verbal memory scores. Model 1 significantly explained 41% of the variance. Results from Model 2 suggest that the Cognitive Efficacy Index explained an additional 24.4%. Thus, Model 2 was interpreted where only the Cognitive Efficacy Index was a significant predictor (p = 0.001). For every 1 unit increase in the Cognitive Efficacy Index, Verbal Memory increased by 41.16. Hypothesis 2's model was significant, accounting for 37.9% of the variance in those with a history of concussion. However, there were no significant unique predictors within the model as age (Wald = 1.26, p = 0.261), King-Devick (Wald = 2.31, p = 0.128), and near point of convergence (Wald = 2.43, p = 0.119) were not significant predictors individually.

CONCLUSIONS

The conflicting findings of this study indicate that baseline data for those with a history of concussion greater than one year may not be comparable to the same metrics during acute concussion episodes. Young athletes who sustain a concussion may be able to overcompensate via the visual system. Future prospective studies with larger sample sizes are required using the proposed model's objective metrics.

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.

Efficacy of aerobic exercise following concussion: a narrative review

Concussion is a type of mild traumatic brain injury which results in symptoms within the physical, cognitive, emotional, and sleep domains. Historically, guidelines established by expert opinion have recommended rest during the initial stages of recovery following a concussion until symptom resolution. However, recent recommendations have shifted to advise an initial period of 24-48 h of rest immediately following concussion with the gradual introduction of light-to-moderate intensity aerobic exercise thereafter. Given the relatively recent transition in recommendations, the aim of this review is to provide an overview of the current literature on the efficacy of aerobic exercise following concussion. The current literature is limited to studies assessing the impact of standardized aerobic exercise following concussion. Upon review, literature suggests participating in aerobic exercise below the point of symptom exacerbation is safe in both the acute and chronic post-concussion symptom stages of recovery and does not delay time to medical clearance. Future large-scale randomized controlled trials assessing the impact of aerobic exercise and differences between males and females would help support the current evidence suggesting aerobic exercise could improve time to recovery following concussion and identify any sex differences in response. As well, future studies with the purpose of identifying optimal aerobic exercise volume and intensity in the treatment of concussion could improve the specificity of the current guidelines.

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.

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

OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Concussion Incidence and Impact on Player Performance in Major League Baseball Players Before and After a Standardized Concussion Protocol

Background:

Sports-related concussions have garnered significant attention in recent years because of the negative effects they can have on a player’s cognitive health and performance. In response to this growing concern, Major League Baseball (MLB) introduced a standardized concussion protocol during the 2011-2012 season.

Purpose/Hypothesis:

The purpose of this study was to compare the reported incidence of concussions and the subsequent performance of MLB players before and after the introduction of the standardized concussion protocol. We hypothesized that the introduction of the standardized concussion protocol would not have an impact on player performance postconcussion.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Players who suffered a concussion between 2001 and 2018 were identified from the MLB transactions page. Incidence and player performance were compared before and after the introduction of the standardized concussion protocol. Player performance was evaluated using traditional data and sabermetric data, which are advanced statistics used in conjunction with standard statistics to better compare players and teams. Player averages were calculated and compared using paired t tests for 30 days before and after concussion, 1 year before and after concussion, and career before and after concussion. Averages were also compared before and after the institution of the standardized concussion protocol using independent-measures t tests.

Results:

There were a total of 114 players who suffered 142 concussions, with 77% of those occurring after the introduction of the concussion protocol (32 before, 110 after). The average time missed because of concussion significantly decreased from 33.7 days (range, 10-122 days) to 18.9 days (range, 6-111 days) after the concussion protocol (P = .0005). There was no difference in player performance (including batting average, on-base percentage, and slugging for batters; earned run average, fielding-independent pitching, and walks plus hits per inning pitched for pitchers) after concussion at any time point (30 days, 1 year, or career) when comparing these statistics before versus after the MLB concussion protocol. However, batter performance was significantly poorer 1 year after concussion and over the remainder of the players' careers (P < .05).

Conclusion:

The number of reported concussions increased after the introduction of the MLB concussion protocol. However, players spent significantly less time on the disabled list without any adverse effect on player performance. Despite these changes, long-term batting performance was significantly poorer after concussion.

Risk and recovery among high school athletes who sustained at least one sports-related concussion

Aim:

Evidence of factors explaining sports-related concussion (SRC) risk and recovery among high school athletes remains inconclusive.

Materials & methods:

Prospective study of a real-world sample of high school athletes (n = 77) who sustained ≤1 SRC. Among those with multiple SRCs, recovery time between events was investigated. To investigate concussion risk, baseline characteristics of athletes with a single versus multiple SRC(s) were compared.

Results:

Recovery time did not differ across events. There were no differences between those with a single versus multiple SRCs.

Conclusion:

Recovery time between initial and subsequent concussive events did not differ, suggesting that prior concussion may not prolong recovery. Baseline characteristics did not explain heightened concussion risk. Investigation of these relationships using more representative samples is needed.

Evidence that prior concussions and pre-injury symptoms explain sports-related concussion (SRC) risk and recovery among high school (HS) athletes remains inconclusive. This may be due to studies investigating HS athletes in medical settings. These athletes may experience more severe SRC, and therefore may not represent risk and recovery in real-world settings. We used a real-world sample of HS athletes to investigate whether prior concussion prolongs recovery for subsequent concussive events. To investigate heightened risk for concussion during the study period, we also examined differences between athletes who sustained a single versus multiple SRC during the study period. There were no differences between those with single versus multiple SRC(s). Based on our real-world sample of HS athletes, recovery time across concussive events during the study period did not differ, suggesting that a prior concussion may not prolong recovery.

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.

The Natural History of Postconcussion Recovery Among High School Athletes

OBJECTIVE

Evaluate postconcussive symptom reporting and recovery.

SETTING

Public high school.

PARTICIPANTS

Unmatched controls (n = 760); students who sustained a sports-related concussion (n = 77); matched controls (gender, grade, sport) (n = 77).

DESIGN

Prospective longitudinal cohort study.

OUTCOME MEASURE

Immediate Postconcussion Assessment and Cognitive Testing.

RESULTS

At baseline, athletes who went on to sustain concussions were more likely than unmatched controls to be younger (P = .02), male (P = .001), and participate in different sports (P < .0001) such as football (concussed = 52%, unmatched controls = 20%). Differences were also noted regarding a previous history of concussion (P = .045; concussed athletes = 26%; unmatched control athletes = 16%) and lifetime number of concussions (P = .05). At baseline, those whose sustained concussions during the study period were more likely than matched controls to report numbness (P = .01) and concentration problems (P = .01) and more likely than unmatched controls to report dizziness (P = .02), sensitivity to light (P = .01), sensitivity to noise (P = .002), and numbness (P = .02). However, when data were reanalyzed and those with a previous history of concussion were removed, differences between those who sustained concussions during the study period and matched controls were no longer significant; when compared to unmatched controls, sensitivity to light (P = .01) and vision problems (P = .04) remained significant. Among those who sustained concussions, median time to recovery was 6 days (95% confidence interval: 4-9), and 71 out of 77 (92%) recovered by the fourth postinjury evaluation (median: 20 days postinjury).

CONCLUSIONS

Course and time frame of recovery were variable. Data also suggest that a previous history of concussion may be contributing to baseline symptom reporting and highlight the potential enduring impact of history of concussion on sensorimotor function. However, further research as to whether preinjury measures of sensorimotor function may increase understanding regarding concussion risk is warranted.