Acute and protracted disruptions to inhibitory control following sports-related concussion

Concussion and executive functions in combat sports: A systematic review

Concussion is a diagnosis given due to trauma caused by abrupt acceleration and deceleration of the brain. The consequences involve, among others, impairments in executive functions. Considering the high incidence of concussions in combat sports, this study investigated the impacts of this trauma on core executive functions. A systematic search was carried out until November 2023, using the PRISMA method on the Virtual Health Library (BVS), PubMed, Science Direct and Scielo platforms. 11 studies, including case studies and quantitative empirical studies, met the eligibility criteria. Risk of bias was assessed using the Cochrane Collaboration risk of bias measurement tool. The results produced high and low bias studies, evaluated by three independent evaluators. Of the 11 studies selected, 91% included samples of boxers and 27.3% included mixed samples (men and women). The total sample was 1,130, aged between 15 and 68 years. 81.9% indicate impairment of executive functions in fighters, with impacts most frequently reported on memory (36.5%) and inhibitory control (27.5%). The results suggest that concussion impairs executive functions in boxing and MMA. However, more studies are needed to relate the diagnosis of concussion to possible deficits in executive functions in combat sports.

Utilizing Augmented Reality to Evaluate Service Member Team Performance

INTRODUCTION

Decision-making is a complex process that relies on situational awareness and experience to create a potential list of actions while weighing the risks and benefits of each action. There is a paucity of data evaluating decision-making for individual service members (SM) during the performance of team-based military-relevant activities. Understanding individual performance and decision-making within the context of a team-based activity has potential to aid in the detection and management of mild traumatic brain injuries and assist with safe and timely return-to-duty decision making. The aim of this project was to evaluate cognitive and motor performance in healthy SM during an augmented reality military specific, team-based activity.

MATERIALS AND METHODS

Data from 110 SMs from Fort Moore Georgia were analyzed for this project. Service members completed 3 augmented reality room breaching and clearing scenarios (Empty Room, Civilian/Combatant, and Incorrect Position of a unit member) with 3 avatar team members. Participants wore a Microsoft HoloLens 2 (HL2) device and used a replica M4 weapon (Haptech Defense Systems) during scenarios. Three-dimensional position data from the HL2 headset was used to compute temporal measures of room breaching and clearing events while the number and timing of weapon discharge was monitored by the M4. Temporal outcomes included time to enter room, time to fire first shot, time in fatal funnel, and total trial time while motor outcomes were distance traveled and average movement velocity.

RESULTS

Pairwise comparisons between the Incorrect Position scenario and the Civilian/Combatant scenario demonstrated no difference in time to enter the room (2.36 seconds in both scenarios). Time to fire the first shot in the Civilian/Combatant scenario was longer (0.97 seconds to 0.58 seconds) while time in fatal funnel (2.58 seconds to 3.31 seconds) and time to trial completion (7.46 seconds to 8.41 seconds) were significantly longer in the Incorrect Position scenario.

CONCLUSIONS

Reaction time to fire the first shot, time in the fatal funnel, and total trial time reflect a change in information-processing and decision-making capabilities during military specific, ecological, team-based scenarios when altering the environment inside of the room and modifying avatar movements. Future studies are planned to evaluate the effects of mild traumatic brain injury on specific aspects of military team performance.

Test-Retest Reliability of Immersive Virtual Reality Measures of Perceptual-Motor Performance

The duration, accuracy, and consistency of responses to various types of stimuli are widely accepted as indirect indicators of the efficiency of brain information processing, but current clinical tests appear to lack sufficient sensitivity to detect subtle impairments. Immersive virtual reality (VR) offers a new means to acquire measures of perceptual-motor responses to moving visual stimuli that require rapid conflict resolution, but their test-retest reliability has not yet been demonstrated. Repeated measures. We analyzed data from 19 healthy young adults who performed a 40-trial VR test on three consecutive days. We focused on response time (RT) and perceptual latency (PL) for eye, neck, arm, and whole-body step displacements involved in executing a reaching/lunging movement in a right or left direction toward a peripherally located virtual target. Measures of RT and PL included a 40-trial mean, an intra-individual variability (IIV) value, and a rate correct score (RCS) that incorporated both response duration and accuracy. Most mean and IIV values for PL and RT demonstrated a positive distributional skew that was substantially reduced by natural logarithm transformation. While a learning effect was evident between sessions 1 and 2 for 7 of 8 mean PL and RT measures, 3-session intraclass correlation coefficient (ICC) values were moderate to excellent for 15 of 16 transformed PL and RT measures (range: .618 to .922). The composite RCS metric did not require transformation for either PL or RT, whose respective 3-session ICC values were .877 and .851. This moderate to excellent test-retest reliability for various VR measures of perceptual-motor function, combined with evidence of their validity from both past and future research, suggest that these measures can advance clinical detection of impaired brain processing and longitudinal assessments of potentially modifiable performance deficiencies.

Subtle impairments of perceptual-motor function and well-being are detectable among military cadets and college athletes with self-reported history of concussion

Introduction

A lack of obvious long-term effects of concussion on standard clinical measures of behavioral performance capabilities does not preclude the existence of subtle neural processing impairments that appear to be linked to elevated risk for subsequent concussion occurrence, and which may be associated with greater susceptibility to progressive neurodegenerative processes. The purpose of this observational cohort study was to assess virtual reality motor response variability and survey responses as possible indicators of suboptimal brain function among military cadets and college athletes with self-reported history of concussion (HxC).

Methods

The cohort comprised 75 college students (20.7 ± 2.1 years): 39 Reserve Officer Training Corp (ROTC) military cadets (10 female), 16 football players, and 20 wrestlers; HxC self-reported by 20 (29.2 ± 27.1 months prior, range: 3-96). A virtual reality (VR) test involving 40 lunging/reaching responses to horizontally moving dots (filled/congruent: same direction; open/incongruent: opposite direction) was administered, along with the Sport Fitness and Wellness Index (SFWI) survey. VR Dispersion (standard deviation of 12 T-scores for neck, upper extremity, and lower extremity responses to congruent vs. incongruent stimuli originating from central vs. peripheral locations) and SFWI response patterns were the primary outcomes of interest.

Results

Logistic regression modeling of VR Dispersion (range: 1.5-21.8), SFWI (range: 44-100), and an interaction between them provided 81% HxC classification accuracy (Model χ ²[2] = 26.03, p < .001; Hosmer & Lemeshow χ ²[8] = 1.86, p = .967; Nagelkerke R ²= .427; Area Under Curve = .841, 95% CI: .734, .948). Binary modeling that included VR Dispersion ≥3.2 and SFWI ≤86 demonstrated 75% sensitivity and 86% specificity with both factors positive (Odds Ratio = 17.6, 95% CI: 5.0, 62.1).

Discussion/Conclusion

Detection of subtle indicators of altered brain processes that might otherwise remain unrecognized is clearly important for both short-term and long-term clinical management of concussion. Inconsistency among neck, upper extremity, and lower extremity responses to different types of moving visual stimuli, along with survey responses suggesting suboptimal well-being, merit further investigation as possible clinical indicators of persisting effects of concussion that might prove to be modifiable.

Dynamic cognitive inhibition in the context of frustration: Increasing racial representation of adolescent athletes using mobile community-engaged EEG methods

Introduction

Concussive events and other brain injuries are known to reduce cognitive inhibition, a key aspect of cognition that supports ones' behaviors and impacts regulation of mood or affect. Our primary objective is to investigate how induction of negative affect (such as frustration) impacts cognitive inhibition and the dynamic process by which youth athletes modulate responses. Secondary objective is to address the lack of Black representation in the scientific literature that promotes brain health and investigates pediatric sports-related brain injury. In particular, neuroscience studies predominantly include White participants despite broad racial representation in sport, in part due to technological hurdles and other obstacles that challenge research access for Black participants.

Methods

Using electroencephalography (EEG), we evaluate the dynamic brain processes associated with cognitive inhibition in the context of frustration induction in adolescent athletes during pre-season conditioning (i.e., prior to contact; N = 23) and a subset during post-season (n = 17).

Results

The N2 component was sensitive to frustration induction (decreased N2 amplitude, slower N2 latency), although effects were less robust at postseason. Trial-by-trial changes indicated a steady decrease of the N2 amplitude during the frustration block during the preseason visit, suggesting that affective interference had a dynamic effect on cognitive inhibition. Lastly, exploratory analyses provide preliminary evidence that frustration induction was less effective for athletes with a previous history of concussion or migraines (trending result) yet more effective for athletes endorsing a history with mental health disorders.

Discussion

We emphasize the urgent need to improve representation in cognitive neuroscience, particularly as it pertains to brain health. Importantly, we provide detailed guides to our methodological framework and practical suggestions to improve representative participation in studies utilizing high-density mobile EEG.

Attention-Deficit/Hyperactivity Disorder-Related Self-Reported Symptoms Are Associated With Elevated Concussion Symptomatology

The aim of the present investigation was to provide insight into how postconcussion symptomatology may be altered in individuals exhibiting attention-deficit/hyperactivity disorder (ADHD)-related behaviors and examine factors that may be responsible for driving such relationships. A total of 99 individuals were assessed during the subacute phase of concussion recovery. Inattentive symptomatology, but not diagnosis of ADHD, was related to greater concussion-symptom severity and overall symptoms endorsed. Cluster and factor analyses highlighted that the relationship between ADHD symptomatology and concussion symptomatology was not a function of overlapping constructs being assessed (i.e., concussion-related symptomatology was not a proxy of ADHD-related symptomatology). These relationships were not mediated by parental observations of impairments in behaviors associated with executive functioning (i.e., executive dysfunction was not driving the greater concussion-related symptomatology associated with ADHD-related symptomatology). These findings highlight the importance of moving beyond categorical frameworks of ADHD to, instead, consider the continuum of underlying behaviors.

Sex Moderates the Relationship between Perceptual-Motor Function and Single-Leg Squatting Mechanics

To examine the isolated and combined effects of sex and perceptual-motor function on single-leg squatting mechanics in males and females. We employed a cross-sectional design in a research laboratory. Fifty-eight females (22.2 ± 3.5 yrs, 1.60 ± .07 m, 64.1 ± 13.0 kg) and 35 males (23.5 ± 5.0 yrs, 1.80 ± .06m, 84.7 ± 15.3 kg) free from time-loss injury in the six months prior, vertigo, and vestibular conditions participated in this study. Independent variables were sex, perceptual-motor metrics (reaction time, efficiency index, conflict discrepancy), and interaction effects. Dependent variables were peak frontal plane angles of knee projection, ipsilateral trunk flexion, and contralateral pelvic drop during single-leg squatting. After accounting for the sex-specific variance and perceptual-motor function effects on frontal plane squatting kinematics, female sex amplified the associations of: higher reaction time, lower efficiency index, and higher conflict discrepancy with greater right ipsilateral peak trunk lean (R² = .13; p = .05); higher reaction time, lower efficiency index, and higher conflict discrepancy with decreased right contralateral pelvic drop (R² = .22; p < .001); higher reaction time and lower conflict discrepancy with greater right frontal plane knee projection angle (R² = .12; p = .03); and higher reaction time with greater left frontal plane knee projection angle (R² = .22; p < .001). Female sex amplified the relationship between perceptual-motor function and two-dimensional frontal plane squatting kinematics. Future work should determine the extent to which perceptual-motor improvements translate to safer movement strategies.

Perceptual-Motor Efficiency and Concussion History Are Prospectively Associated With Injury Occurrences Among High School and Collegiate American Football Players

Background:

After a sport-related concussion (SRC), the risk for lower extremity injury is approximately 2 times greater, and the risk for another SRC may be as much as 3 to 5 times greater.

Purpose:

To assess the predictive validity of screening methods for identification of individual athletes who possess an elevated risk of SRC.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

Metrics derived from a smartphone flanker test software application and self-ratings of both musculoskeletal function and overall wellness were acquired from American high school and college football players before study participation. Occurrences of core or lower extremity injury (CLEI) and SRC were documented for all practice sessions and games for 1 season. Receiver operating characteristic and logistic regression analyses were used to identify variables that provided the greatest predictive accuracy for CLEI or SRC occurrence.

Results:

Overall, there were 87 high school and 74 American college football players included in this study. At least 1 CLEI was sustained by 45% (39/87) of high school players and 55% (41/74) of college players. Predictors of CLEI included the flanker test conflict effect ≥69 milliseconds (odds ratio [OR], 2.12; 90% CI, 1.24-3.62) and a self-reported lifetime history of SRC (OR, 1.70; 90% CI, 0.90-3.23). Of players with neither risk factor, only 38% (29/77) sustained CLEI compared with 61% (51/84) of players with 1 or both of the risk factors (OR, 2.56; 90% CI, 1.50-4.36). SRC was sustained by 7 high school players and 3 college players. Predictors of SRC included the Overall Wellness Index score ≤78 (OR, 9.83; 90% CI, 3.17-30.50), number of postconcussion symptoms ≥4 (OR, 8.35; 90% CI, 2.71-25.72), the Sport Fitness Index score ≤78 (OR, 5.16; 90% CI, 1.70-15.65), history of SRC (OR, 4.03; 90% CI, 1.35-12.03), and the flanker test inverse efficiency ratio ≥1.7 (OR, 3.19; 90% CI, 1.08-9.47).

Conclusion:

Survey responses and smartphone flanker test metrics predicted greater injury incidence among individual football players classified as high-risk compared with that for players with a low-risk profile.

A Novel Approach to Assessment of Perceptual-Motor Efficiency and Training-Induced Improvement in the Performance Capabilities of Elite Athletes

Standard clinical assessments of mild traumatic brain injury are inadequate to detect subtle abnormalities that can be revealed by sophisticated diagnostic technology. An association has been observed between sport-related concussion (SRC) and subsequent musculoskeletal injury, but the underlying neurophysiological mechanism is not currently understood. A cohort of 16 elite athletes (10 male, 6 female), which included nine individuals who reported a history of SRC (5 male, 4 female) that occurred between 4 months and 8 years earlier, volunteered to participate in a 12-session program for assessment and training of perceptual-motor efficiency. Performance metrics derived from single- and dual-task whole-body lateral and diagonal reactive movements to virtual reality targets in left and right directions were analyzed separately and combined in various ways to create composite representations of global function. Intra-individual variability across performance domains demonstrated very good SRC history classification accuracy for the earliest 3-session phase of the program (Reaction Time Dispersion AUC = 0.841; Deceleration Dispersion AUC = 0.810; Reaction Time Discrepancy AUC = 0.825, Deceleration Discrepancy AUC = 0.794). Good earliest phase discrimination was also found for Composite Asymmetry between left and right movement directions (AUC = 0.778) and Excursion Average distance beyond the minimal body displacement necessary for virtual target deactivation (AUC = 0.730). Sensitivity derived from Youden's Index for the 6 global factors ranged from 67 to 89% and an identical specificity value of 86% for all of them. Median values demonstrated substantial improvement from the first 3-session phase to the last 3-session phase for Composite Asymmetry and Excursion Average. The results suggest that a Composite Asymmetry value ≥ 0.15 and an Excursion Average value ≥ 7 m, provide reasonable qualitative approximations for clinical identification of suboptimal perceptual-motor performance. Despite acknowledged study limitations, the findings support a hypothesized relationship between whole-body reactive agility performance and functional connectivity among brain networks subserving sensory perception, cognitive decision-making, and motor execution. A complex systems approach appears to perform better than traditional data analysis methods for detection of subtle perceptual-motor impairment, which has the potential to advance both clinical management of SRC and training for performance enhancement.

Paired cognitive flexibility task with symptom factors improves detection of sports-related concussion in high school and collegiate athletes

Determining the sensitivity and specificity of short neurocognitive assessments to objectively detect concussion will help clinicians more confidently integrate such tools in clinical management decisions. This study quantified the sensitivity and specificity of a computerized cognitive flexibility task isolating shifts of visuospatial attention in combination with clinical symptoms acutely (< 72 h) following concussion. A total of 100 athletes (53 concussed; 47 non-injured control; 42% female) completed computerized neurocognitive testing and clinical symptom reports (Sport Concussion Assessment Tool 3rd edition: SCAT3). Separate discriminant function analyses were performed for individual, combination, and stepwise inclusion of neurocognitive and clinical symptomology assessments. Findings revealed the combination of neurocognitive outcomes (i.e., mean reaction time, response accuracy, and response accuracy cost) with clinical symptom factor scores exhibited the greatest sensitivity (95.7%) and specificity (88.7%) as well as the highest positive predictive value (95.9%) and negative predictive value (88%) relative to other approaches. Further, a stepwise approach predicting concussion status using the discriminant functions improved detection of concussion (98.2% sensitivity, 95.7% specificity, 96.4% positive predictive value, and 97.8% negative predictive value) when clinical symptom factors failed to indicate the presence of a concussion. Incorporating a cognitive flexibility task involving shifts of visuospatial attention combined with clinical symptom factor scores may improve clinical decision-making as this approach exceeds the sensitivity and specificity of widely popular neurocognitive test batteries and takes less than 10 min to administer.

Post-exercise cognitive testing to assess persisting alterations in athletes with a history of concussion

Primary Objective: To determine whether a physical exercise protocol could reveal persistent cognitive alterations in university athletes with a history of concussion (HOC). Thirty-four HOC and 34 controls participated in this study.Research Design: Cross-sectional.Methods and Procedures: The exercise protocol consisted of a 20-min bout on a stationary bike at 80% of the theoretical maximal heart rate. Before and after the exercise, participants performed a computerized switch task designed specifically to recruit executive functions. Group × Condition (pre- and post-exercise) repeated measures of ANCOVAs for accuracy, reaction time, and inverse efficiency score on the switch task were conducted. Chi-square tests were run to determine if the proportion of HOC and controls who underperformed (at least 2SD lower than the control group's average score) at rest and post-exercise were similar. Whilst no interaction or main effects were found with ANCOVAs, significantly more HOC athletes (21%) underperformed following exercise than at rest (3%) on the switch task, p = .02. The current results indicate that an acute bout of exercise can reveal persistent alterations that are not present at rest in the protracted phase of concussion. They also highlight the importance of considering inter-individual differences in recovery trajectories.

Upper-Extremity Perceptual-Motor Training Improves Whole-Body Reactive Agility Among Elite Athletes With History of Sport-Related Concussion

CONTEXT

Sport-related concussion (SRC) elevates risk for subsequent injury, which may relate to impaired perceptual-motor processes that are potentially modifiable.

OBJECTIVE

To assess a possible upper-extremity (UE) training effect on whole-body (WB) reactive agility performance among elite athletes with history of SRC (HxSRC) and without such history of SRC.

DESIGN

Cohort study.

SETTING

Residential training center.

PARTICIPANTS

Elite athletes (12 males and 8 females), including 10 HxSRC and 10 without such history of SRC.

INTERVENTION

One-minute training sessions completed 2 to 3 times per week over a 3-week period involved verbal identification of center arrow direction for 10 incongruent and 10 congruent flanker test trials with simultaneous reaching responses to deactivate illuminated buttons.

MAIN OUTCOME MEASURES

Pretraining and posttraining assessments of UE and WB reactive responses included flanker test conflict effect (incongruent minus congruent reaction time) and WB lateral average asymmetry derived from reaction time, speed, acceleration, and deceleration in opposite directions. Discrimination was assessed by receiver operating characteristic analysis, and training effect was assessed by repeated-measures analysis of variance.

RESULTS

Pretraining discrimination between HxSRC and without such history of SRC was greatest for conflict effect ≥80 milliseconds and WB lateral average asymmetry ≥18%. Each athlete completed 6 training sessions, which improved UE mean reaction time from 767 to 646 milliseconds (P < .001) and reduced mean conflict effect from 96 to 53 milliseconds (P = .039). A significant group × trial interaction was evident for WB lateral average asymmetry (P = .004), which was reduced from 24.3% to 12.5% among those with HxSRC.

CONCLUSIONS

Suboptimal perceptual-motor performance may represent a subtle long-term effect of concussion that is modifiable through UE training, which appears to improve WB reactive capabilities.

Wellness Survey Responses and Smartphone App Response Efficiency: Associations With Remote History of Sport-Related Concussion

Recent research findings have strongly suggested that sport-related concussion (SRC) increases risk for subsequent injury of any type, as well as a potential for long-term adverse effects on neurological and psychological well-being. The primary purpose of this study was to explore the reliability and discriminatory power of clinical testing procedures for detecting persisting effects of SRC. We used a cross-sectional study design to assess both self-reported symptoms commonly associated with post-concussion syndrome, and the effects of mental or physical activity on metrics derived from a smartphone app designed to test perceptual-motor responses. Among 30 physically active college students, 15 participants reported a SRC occurrence prior to testing (M time-since-injury = 4.0 years, SD = 3.1, range = 5 months to 11 years). We found good test-retest reliability for key metrics derived from the smartphone app (ICC ≥ .70); and the internal consistency for the Overall Wellness Index (OWI) for 10 categories of 82 post-concussion symptoms was ideal (Cronbach's α ≥ .80). Moderate intensity treadmill running demonstrated the strongest differential effect on perceptual-motor responses between participants with a history of SRC (HxSRC) and those with no such history (No SRC), which was best represented by the speed-accuracy trade-off quantified by the inverse efficiency index (IEI: group X trial interaction p = .055). Self-reported OWI symptoms ≥4 and post-physical activity IEI ≥ 568 ms provided the strongest discrimination between HxSRC and NoSRC participants (≥1 versus 0: OR = 9.75). Our findings suggest that persisting effects from a remote SRC occurrence can be detected by easily administered screening procedures that have the potential to identify individual athletes who might derive benefit from interventions to restore their optimal function and well-being.

Mouse Tracking to Explore Motor Inhibition Processes in Go/No-Go and Stop Signal Tasks

Response inhibition relies on both proactive and reactive mechanisms that exert a synergic control on goal-directed actions. It is typically evaluated by the go/no-go (GNG) and the stop signal task (SST) with response recording based on the key-press method. However, the analysis of discrete variables (i.e., present or absent responses) registered by key-press could be insufficient to capture dynamic aspects of inhibitory control. Trying to overcome this limitation, in the present study we used a mouse tracking procedure to characterize movement profiles related to proactive and reactive inhibition. A total of fifty-three participants performed a cued GNG and an SST. The cued GNG mainly involves proactive control whereas the reactive component is mainly engaged in the SST. We evaluated the velocity profile from mouse trajectories both for responses obtained in the Go conditions and for inhibitory failures. Movements were classified as one-shot when no corrections were observed. Multi-peaked velocity profiles were classified as non-one-shot. A higher proportion of one-shot movements was found in the SST compared to the cued GNG when subjects failed to inhibit responses. This result suggests that proactive control may be responsible for unsmooth profiles in inhibition failures, supporting a differentiation between these tasks.

Effects of Tai Chi Chuan on Inhibitory Control in Elderly Women: An fNIRS Study

Background

Inhibitory control is a sub-ability of executive function and plays an important role in the entire cognitive process. However, declines in inhibitory control during aging significantly impair the quality of life of elderly people. Investigating methods to delay the decline of inhibitory control has become a focal point in current research. Tai Chi Chuan (TCC) is one effective method used to delay cognitive declines in older adults. However, the specific effects of TCC on inhibitory control and the mechanisms through which TCC may improve cognition in older adults have not been comprehensively investigated.

Objective

The study explores possible neurological mechanisms related to the effects of TCC interventions on inhibitory control in older people using a functional near-infrared spectroscopy (fNIRS) technique and reaction times (RTs).

Methods

A total of 26 healthy, elderly people who had not received TCC training completed all study procedures. The subjects were randomized to either the TCC group or the control group. Subjects in the TCC group were taught TCC by a certified instructor and trained for 8 weeks. The control group continued to perform general daily activities. The Flanker task was administered to every participant to evaluate inhibitory control pre- and post-intervention. While participants were performing the Flanker task, fNIRS data were collected.

Results

Post-intervention, significant differences for incongruent flankers were found only for the TCC intervention group. Faster RTs were observed for the incongruent flankers in the TCC group than in the control group (p < 0.05). Analysis of the fNIRS data revealed an increase in oxy-Hb in the prefrontal cortex during the incongruent flankers after the TCC exercise intervention.

Conclusion

The TCC intervention significantly improved inhibitory control in older adults, suggesting that TCC is an effective, suitable exercise for improving executive function and neurological health in elderly people.

Clinical Trial Registration

Chinese Clinical Trial Register, ChiCTR1900028457.