Immersive Real-Time Biofeedback Optimized With Enhanced Expectancies Improves Motor Learning: A Feasibility Study.

CONTEXT: An Optimizing Performance through Intrinsic Motivation and Attention for Learning theory-based motor learning intervention delivering autonomy support and enhanced expectancies (EE) shows promise for reducing cognitive-motor dual-task costs, or the relative difference in primary task performance when completed with and without a secondary cognitive task, that facilitate adaptive injury-resistant movement response. The current pilot study sought to determine the effectiveness of an autonomy support versus an EE-enhanced virtual reality motor learning intervention to reduce dual-task costs during single-leg balance. DESIGN: Within-subjects 3 × 3 trial. METHODS: Twenty-one male and 24 female participants, between the ages of 18 and 30 years, with no history of concussion, vertigo, lower-extremity surgery, or lower-extremity injuries the previous 6 months, were recruited for training sessions on consecutive days. Training consisted of 5 × 8 single-leg squats on each leg, during which all participants mimicked an avatar through virtual reality goggles. The autonomy support group chose an avatar color, and the EE group received positive kinematic biofeedback. Baseline, immediate, and delayed retention testing consisted of single-leg balancing under single- and dual-task conditions. Mixed-model analysis of variances compared dual-task costs for center of pressure velocity and SD between groups on each limb. RESULTS: On the right side, dual-task costs for anterior-posterior center of pressure mean and SD were reduced in the EE group (mean Δ = -51.40, Cohen d = 0.80 and SD Δ = -66.00%, Cohen d = 0.88) compared with the control group (mean Δ = -22.09, Cohen d = 0.33 and SD Δ = -36.10%, Cohen d = 0.68) from baseline to immediate retention. CONCLUSIONS: These findings indicate that EE strategies that can be easily implemented in a clinic or sport setting may be superior to task-irrelevant AS approaches for influencing injury-resistant movement adaptations.

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.

Neuromechanical Considerations for Postconcussion Musculoskeletal Injury Risk Management.

Recent epidemiological studies have documented increased susceptibility to musculoskeletal injury after sport-related concussion, which raises questions about the adequacy of current clinical practices to ensure safe return to sport. A growing body of evidence derived from advanced neuroimaging and neurological assessment methods strongly suggests that mild traumatic brain injury has long-lasting adverse effects that persist beyond resolution of clinical symptoms. Plausible interrelationships among postconcussion changes in brain structure and function support the rationale for specific methods of clinical assessment and training to target the interaction of cognitive and motor function for reduction of musculoskeletal injury risk after concussion. The findings of preliminary clinical studies are presented to support suggested strategies for reduction of postconcussion musculoskeletal injury risk, and to identify novel approaches that we consider worthy areas for further research.

Assessment and Training of Perceptual-Motor Function: Performance of College Wrestlers Associated with History of Concussion.

Concussion may affect sport performance capabilities related to the visual perception of environmental events, rapid decision-making, and the generation of effective movement responses. Immersive virtual reality (VR) offers a means to quantify, and potentially enhance, the speed, accuracy, and consistency of responses generated by integrated neural processes. A cohort of 24 NCAA Division I male wrestlers completed VR assessments before and after a 3-week VR training program designed to improve their perceptual-motor performance. Prior to training, the intra-individual variability (IIV) among 40 successive task trials for perceptual latency (i.e., time elapsed between visual stimulus presentation and the initiation of movement response) demonstrated strong discrimination between 10 wrestlers who self-reported a history of concussion from 14 wrestlers who denied ever having sustained a concussion (Area Under Curve ≥ 0.750 for neck, arm, and step movements). Natural log transformation improved the distribution normality of the IIV values for both perceptual latency and response time (i.e., time elapsed between visual stimulus presentation and the completion of movement response). The repeated measures ANOVA results demonstrated statistically significant (p < 0.05) pre- and post-training differences between groups for the IIV in perceptual latency and the IIV in response time for neck, arm, and step movements. Five of the six IIV metrics demonstrated a statistically significant magnitude of change for both groups, with large effect sizes. We conclude that a VR assessment can detect impairments in perceptual-motor performance among college wrestlers with a history of concussion. Although significant post-training group differences were evident, VR training can yield significant performance improvements in both groups.

Either Autonomy Support or Enhanced Expectancies Delivered Via Virtual-Reality Benefits Frontal-Plane Single-Leg Squatting Kinematics.

Our purpose in this study was to determine the effects of a virtual reality intervention delivering specific motivational motor learning manipulations of either autonomy support (AS) or enhanced expectancies (EE) on frontal plane single-leg squatting kinematics. We allocated 45 participants (21 male, 24 female) demonstrating knee, hip, and trunk frontal plane mechanics associated with elevated anterior cruciate ligament injury risk to one of three groups (control, AS, or EE). Participants mimicked an avatar performing five sets of eight repetitions of exemplary single-leg squats. AS participants were given the added option of choosing the color of their avatar. EE participants received real-time biofeedback in the form of green highlights on the avatar that remained on as long as the participant maintained pre-determined 'safe' frontal plane mechanics. We measured peak frontal plane knee, hip, and trunk angles before (baseline) and immediately following (post) the intervention. The control group demonstrated greater increases in knee abduction angle (Δ = +2.3°) than did the AS (Δ = +0.1°) and EE groups (Δ = -0.4°) (p = .003; η2p = .28). All groups demonstrated increased peak hip adduction (p = .01, ηp2 = .18) (control Δ = +1.5°; AS Δ = +3.2°; EE Δ = +0.7°). Hip adduction worsened in all groups. AS and EE motivation strategies appeared to mitigate maladaptive frontal plane knee mechanics.

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.

A Neuro-Integrative Assessment of Perceptual-Motor Performance and Wellness in ROTC Cadets.

Resting heart rate variability (HRV) may be a useful index of both brain-based executive function and general health. Our purpose in this study was to quantify relationships among HRV, perceptual-motor performance metrics, and wellness survey responses. A cohort of 32 male Reserve Officer Training Corp (ROTC) cadets completed a dual-task upper extremity reaction time (UERT) test, two tests of whole-body reactive agility, and a 10-item wellness survey that produced a 0-100 Overall Wellness Index (OWI). We averaged participants' resting HRV measurements twice per week over 10 weeks to derive an intra-individual grand mean (HRV-IIGM) and over a series of days we calculated an intra-individual coefficient of variation (HRV-IICV). We used median values for the two HRV metrics (HRV-IIGM and HRV-IICV) to separate the cadets into equal-sized high and low HRV groups to form the dependent variable for logistic regression analyses. We found a significant inverse relationship between HRV-IIGM and HRV-IICV (r = -0.723, p < .001). Differences in UERT in the left versus right visual hemifields (L-R Diff) and OWI scores were strongly related to both HRV-IIGM ≤ 4.49 and HRV-IICV ≥ 6.95%. Logistic regression models that included L-R Diff and OWI showed 71% classification accuracy for HRV-IIGM (Model χ2 [2] = 12.47, p = .002, Nagelkerke R2 = 0.430) and 81% classification accuracy for HRV-IICV (Model χ2 [2] = 14.88, p = .001, Nagelkerke R2 = 0.496). These findings suggest that resting HRV, perceptual-motor efficiency, and overall wellness are highly interrelated, supporting a multi-factor biopsychosocial assessment to guide the design and implementation of interventions to maximize operational effectiveness for ROTC cadets and other military personnel.

Changes in dual-task cognitive performance elicited by physical exertion vary with motor task.

Background: Integrated movement and cognitive load paradigms are used to expose impairments associated with concussion and musculoskeletal injury. There is currently little information on the discriminatory nature of dual-task complexity and the relative influence of physical exertion on cognitive outcomes. Purpose: Assess cognitive performance while under motor conditions of increasing complexity before and after a standardized exercise protocol. Methods: 34 participants were recruited (17 male and 17 female; 24 ± 1.4 yrs). A modified Eriksen flanker test was used to assess cognitive performance under four conditions (seated, single-leg stance, walking, and lateral stepping) before and after a 20-min moderate-to vigorous intensity treadmill protocol. The flanker test consisted of 20 sets of 5-arrow configurations, appearing in random order. To complete the response to cognitive stimulus, participants held a smartphone horizontally and were instructed to respond as quickly and as accurately as possible by tilting the device in the direction corresponding to the orientation of the middle arrow. The metrics used for analysis included average reaction time (ms), inverse efficiency index (average reaction time penalized for incorrect responses), and conflict effect (the average time cost of responding to an incongruent repetition vs. a congruent repetition). Mixed effects (condition by time) RMANOVAs were conducted to examine the effects of motor task complexity and physical exertion on cognitive performance. Results: There was a condition by time interaction for inverse efficiency index (p < 0.001), in which participants displayed higher cognitive efficiency for the pre-activity lateral stepping condition compared to the other three conditions (Cohen's d = 1.3-1.6). For reaction time and conflict effect, there were main effects for condition (p = 0.004 and 0.006, respectively), in which performance during lateral stepping was improved in relation to the seated condition (reaction time Cohen's d = 0.68; conflict effect Cohen's d = 0.64). Conclusion: Participants tended to display better dual-task cognitive performance under more stimulating or complex motor tasks before physical exertion, likely associated with the inverted-U arousal-performance relationship. When using dual-task assessments, clinicians should be mindful of the accompanying motor task and baseline exertion levels and their potential to disrupt or optimize cognitive performance.

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.

Reliability and concurrent validity of TRAZER compared to three-dimensional motion capture.

BACKGROUND: Efficient neural processing of visuospatial and proprioceptive input appears to be crucial for avoidance of sport injury. As such, clinically-feasible tests are needed to identify deficiencies found by advanced neuroimaging and electrophysiological tests. Three-dimensional motion capture in a laboratory setting is currently the gold standard for measurement of human movement parameters but is costly and requires extensive training. Non-immersive virtual reality systems with body motion tracking, such as TRAZER, may provide a clinically-feasible and portable means of acquiring similar variables. Test-retest reliability and concurrent validity of these systems are currently lacking. AIM: The aim of the study was to assess the concurrent validity of the TRAZER single-camera system with 3D motion capture system and to assess the test-retest reliability of TRAZER's whole-body reactive agility metrics. METHODS: Participants - For validity, 13 healthy individuals (24.8±3.1 years, 170.0±7.7 cm, 70.0±14.2 kg); for reliability, 18 healthy individuals (23.3±2.5 years, 168.2±11.2 cm, 78.2±17.8 kg). Design - Validity was a single-session cross-sectional study. Reliability was a 3 consecutive day test-retest study. Setting-Controlled laboratory study. Intervention - Assessments utilized randomized movements in eight directions for forty total repetitions as designated by the TRAZER system. TRAZER protocol was simultaneously tracked by Vicon Motion Capture and the TRAZER system. Reliability data were captured on three consecutive days by the TRAZER system. Main Outcome Measures - Maximum acceleration, maximum velocity, and total distance were recorded for validation. In addition to these measures, maximum deceleration, average velocity, average acceleration, average deceleration, and average reaction time were collected for reliability. RESULTS: Overall, a lack of agreement exists between maximum outputs for TRAZER and 3D motion capture (velocity r=0.808, acceleration r=-0.090), but total distance correlation was high (r =.961). ICC values between days 1-2-3 for average measures were high (average velocity=0.847, average acceleration=0.919, and average deceleration=0.948) with the exception of average reaction time being fair (ICC=0.536). ICCs for maximum measures showed a much smaller correlation between days (velocity=0.654, acceleration=0.171, and deceleration=0.416). CONCLUSIONS: Even though there is a lack of strong concurrent validity between measures obtained from TRAZER and 3D motion capture systems, there is strong test-retest reliability of the TRAZER system. The applicability of these findings makes TRAZER clinically relevant in scenarios requiring pre- and post-testing for return to play decisions, or monitoring of a training regimen where demonstration of validation to a gold standard measurement is not relevant. RELEVANCE FOR PATIENTS: When test-retest capability is desired, such as in return-to-play protocols following an injury, Trazer is a reliable option.

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.