The Effect of Exercise on a Novel Dual-Task Assessment for Sport Concussion

PURPOSE

This study aimed to determine the effect of exercise on cognitive and motor performance and the subsequent test-retest reliability of a novel dual-task (DT) assessment in nonconcussed college students.

METHODS

Sixty nonconcussed college students (53.3% female) with an average age (±SD) of 20.5 ± 1.34 yr, height of 171.7 ± 9.33 cm, and mass of 69.3 ± 12.23 kg were included in the study. Participants were assigned to an exercise ( n = 30) or rest ( n = 30) intervention group and completed two study visits that were separated by a 2-wk test-retest interval. At each visit, participants completed a novel DT assessment that consisted of the concurrent administration of the Standardized Assessment of Concussion (SAC) and tandem gait (TG) before the exercise or rest intervention. After the DT assessment at the first visit, participants in the exercise group performed moderate-intensity exercise, whereas the rest group sat quietly for 30 min. After the intervention, both groups were readministered the DT assessment. At the second visit, the same procedures were followed, except that each group was administered the opposite intervention (e.g., the exercise group completed the rest intervention). A composite TG (cTG) score was calculated by summing the average time to complete the TG pattern during each SAC domain (immediate memory, digits backwards, months in reverse order, delayed recall). An ANCOVA was conducted to assess postintervention differences while controlling for preintervention performance. Test-retest reliability was assessed using intraclass correlation coefficients (ICC 3,2 ) with 95% confidence intervals, with all analyses performed with α = 0.05.

RESULTS

SAC and cTG performance was similar ( P values > 0.05) from preintervention to postintervention for the rest or exercise protocols. Good (rest: ICC = 0.77 (0.62-0.87); exercise: ICC = 0.84 (0.73-0.90)) and excellent (rest: ICC = 0.97 (0.94-0.98); exercise: ICC = 0.93 (0.88-0.96)) test-retest reliabilities were observed for the SAC composite score and cTG score, respectively.

CONCLUSIONS

Our DT assessment was robust to the influence of moderate-intensity exercise and demonstrated good-to-excellent test-retest reliability in a healthy collegiate sample.

The Clinical Utility of the Child SCAT5 for Acute Concussion Assessment

Background

The Child Sport Concussion Assessment Tool 5th Edition (Child SCAT5) was developed to evaluate children between 5 and 12 years of age for a suspected concussion. However, limited empirical evidence exists demonstrating the value of the Child SCAT5 for acute concussion assessment. Therefore, the purpose of our study was to examine differences and assess the diagnostic properties of Child SCAT5 scores among concussed and non-concussed middle school children on the same day as a suspected concussion.

Methods

Our participants included 34 concussed (21 boys, 13 girls; age = 12.8 ± 0.86 years) and 44 non-concussed (31 boys, 13 girls; age = 12.4 ± 0.76 years) middle school children who were administered the Child SCAT5 upon suspicion of a concussion. Child SCAT5 scores were calculated from the symptom evaluation (total symptoms, total severity), child version of the Standardized Assessment of Concussion (SAC-C), and modified Balance Error Scoring System (mBESS). The Child SCAT5 scores were compared between the concussed and non-concussed groups. Non-parametric effect sizes (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r=\frac{Z}{\sqrt{n}}$$\end{document}r=Zn) were calculated to assess the magnitude of difference for each comparison. The diagnostic properties (sensitivity, specificity, diagnostic accuracy, predictive values, likelihood ratios, and diagnostic odds ratio) of each Child SCAT5 score were also calculated.

Results

Concussed children endorsed more symptoms (p < 0.001, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.45), higher symptom severity (p < 0.001, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.44), and had higher double leg (p = 0.046, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.23), single leg (p = 0.035, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.24), and total scores (p = 0.022, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$r$$\end{document}r=0.26) for the mBESS than the non-concussed children. No significant differences were observed for the SAC-C scores (p’s ≥ 0.542). The quantity and severity of endorsed symptoms had the best diagnostic accuracy (AUC = 0.76–0.77), negative predictive values (NPV = 0.84–0.88), and negative likelihood ratios (-LR = 0.22–0.31) of the Child SCAT5 scores.

Conclusions

Clinicians should prioritize interpretation of the symptom evaluation form of the Child SCAT5 as it was the most effective component for differentiating between concussed and non-concussed middle school children on the same day as a suspected concussion.

Reevaluating clinical assessment outcomes after unrestricted return to play following sport-related concussion

PRIMARY OBJECTIVE

The objective of this study was to examine neurocognition, postural control, and symptomology at multiple timepoints following concussion. We hypothesized that collegiate athletes would perform similar to or better than their baseline in terms of each outcome at both timepoints.

RESEARCH DESIGN

This was a retrospective study of 71 collegiate athletes (18.3 ± 0.89 years old; 182.2 ± 10.05 cm; 84.2 ± 20.07 kg) to observe changes in outcomes from a previously established clinical protocol.

METHODS AND PROCEDURES

Participants were administered ImPACT™, the Sensory Organization Test (SOT), and the revised head injury scale (HIS-r) prior to their seasons (baseline); upon reporting symptom-free following concussion (post-injury); and approximately 8-months after return-to-play to establish a new baseline.

MAIN OUTCOMES AND RESULTS

There were no changes in ImPACT scores or HIS-r reporting over time. ImPACT total symptom score (TSS) decreased over time (p = .002, η_p² = 0.08). Significant main effects occurred for the SOT equilibrium score (p < .01, η_p² = 0.34) and Vestibular sensory ratio (p < .001, η_p² = 0.22).

CONCLUSIONS

Our data suggest no decline in neurocognition, balance, or symptom burden approximately eight months post-injury. As clinicians continue to explore "best practices" for concussion management and potential long-term implications of these injuries it is important to monitor outcome measures longitudinally.

The Effect of Muscle Activation on Head Kinematics During Non-injurious Head Impacts in Human Subjects

In this study, twenty volunteers were subjected to three, non-injurious lateral head impacts delivered by a 3.7 kg padded impactor at 2 m/s at varying levels of muscle activation (passive, co-contraction, and unilateral contraction). Electromyography was used to quantify muscle activation conditions, and resulting head kinematics were recorded using a custom-fit instrumented mouthpiece. A multi-modal battery of diagnostic tests (evaluated using neurocognitive, balance, symptomatic, and neuroimaging based assessments) was performed on each subject pre- and post-impact. The passive muscle condition resulted in the largest resultant head linear acceleration (12.1 ± 1.8 g) and angular velocity (7.3 ± 0.5 rad/s). Compared to the passive activation, increasing muscle activation decreased both peak resultant linear acceleration and angular velocity in the co-contracted (12.1 ± 1.5 g, 6.8 ± 0.7 rad/s) case and significantly decreased in the unilateral contraction (10.7 ± 1.7 g, 6.5 ± 0.7 rad/s) case. The duration of angular velocity was decreased with an increase in neck muscle activation. No diagnostic metric showed a statistically or clinically significant alteration between baseline and post-impact assessments, confirming these impacts were non-injurious. This study demonstrated that isometric neck muscle activation prior to impact can reduce resulting head kinematics. This study also provides the data necessary to validate computational models of head impact.

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.

A-16 The Clinical Utility of a Novel Dual-Task Assessment for Sport-Related Concussion in Collegiate Athletes

Objective

To compare the clinical utility of a novel dual-task assessment for sport-related concussion (SRC) to other commonly-used clinical measures in collegiate athletes.

Method

Participants consisted of 38 collegiate athletes (19 concussed and 19 matched comparisons, 53% male, age = 20.0 ± 1.34 years, height = 178.2 ± 12.12 cm, mass = 83.4 ± 21.89 kg). Participants were administered the dual-task assessment, Balance Error Scoring System (BESS), Standardized Assessment of Concussion (SAC), and tandem gait (TG) test within 48 hours (T1), at 5 days (T2), and when symptom-free (T3) following a diagnosed SRC. The novel dual-task assessment consisted of concurrent administration of the SAC and TG. The ImPACT and Sensory Organization Test (SOT) were administered at T3 in alignment with the university’s concussion management policy. Sensitivity, specificity, and diagnostic accuracy using receiver operator curve analyses were calculated for each measure for T1-T3 using previously established interpretation guidelines.

Results

For sensitivity, a range of values were observed from T1-T3 for the dual-task (88%–37%), BESS (47%–47%), SAC (53%–26%), TG test (53%–11%). Similarly, a range of specificity values were observed for the dual-task (58%–84%), BESS (84%–63%), SAC (79%–84%), and TG test (95%–100%) from T1-T3. At T3, the ImPACT and SOT were observed to have a sensitivity of 32% and 100% and specificity of 16% and 100%, respectively. A range of diagnostic accuracy values were observed from T1-T3 for the dual-task (84%–62%), BESS (59%–50%), SAC (64%–56%), TG test (82%–71%), ImPACT (T3 = 66%), and SOT (T3 = 50%).

Conclusions

The dual-task assessment had comparable or higher diagnostic accuracy as other commonly-used clinical measures of SRC throughout clinical recovery in collegiate athletes.

If Not Now, When? An Absence of Neurocognitive and Postural Stability Deficits in Collegiate Athletes with One or More Concussions

A history of concussion has been associated with decreased neurocognitive function and postural control. The purpose of our study was to compare neurocognitive function and postural control in collegiate athletes with and without varying histories of concussion. Collegiate athletes were divided into groups based on 0 (n = 129), 1 (n = 91), 2 (n = 52), and 3+ (n = 34) prior concussions. Participants in each group were carefully matched by sport, sex, height, weight, and age. Athletes were administered the Immediate Post-Concussion Assessment and Cognitive Test (ImPACT™) and the Sensory Organization Test (SOT) as part of a standard of care pre-season assessment. Group ImPACT (Verbal and Visual Memory, Visual Motor Speed, and Reaction Time) and SOT (Equilibrium Score and Somatosensory, Visual, and Vestibular sensory ratios) outcome scores were compared using one-way analyses of variance (ANOVAs). Coefficients of variation (CVs) were also calculated for each outcome score and were compared using two-sample tests with 95% confidence intervals (CIs). Participants with and without a history of concussion were not significantly different for any ImPACT or SOT outcome score (p's > 0.10). Groups (0, 1, 2, and 3+ previous concussions) were not different from each other for any ImPACT or SOT outcome score (p's ≥ 0.11). Likewise, the CVs associated with each ImPACT and SOT outcome score did not vary significantly between outcome scores for any group comparison (p ≥ 0.09). Our findings suggest that a history of one or more concussions does not influence neurocognitive performance or postural stability in collegiate athletes at their pre-season baseline assessment.

The Influence of Hormonal Contraceptives on Baseline ImPACT Performance

Purpose

Our study examined the influence of hormonal contraceptives (HC) on pre-injury (baseline) ImPACT performance in female collegiate athletes.

Methods

Participants in our cross-sectional study consisted of 304 NCAA Division I female athletes who self-reported taking (HC+ [n=154]) or not taking (HC- [n=154]) HC. HC+ participants were matched to HC- participants for height, weight, sport, and position. HC+ participants had an average age of 19.0±1.33 years, height of 170.5–8.70 cm, and mass of 64.2–10.58 kg. HC- participants had an average age of 19.0±1.24 years, height of 170.3–9.19 cm, and mass of 64.2–9.75 kg. Participants completed ImPACT as part of their preseason baseline assessment. Only participants with valid ImPACT assessments were included in our analyses. Chi-squared (χ2) tests were performed to compare groups in terms of medical history variables. Independent t-tests were used to compare groups in terms of demographic variables, self-reported hours of sleep, and ImPACT (Verbal and Visual Memory, Visual Motor Speed [VMS], Reaction Time [RT], and Total Symptom Severity [TSS]) outcome scores. Analyses were performed with α=0.05.

Results

No differences were observed between groups for demographic variables, hours of sleep, or medical history variables (p<0.05). For VMS, the HC- group (42.9+5.63) scored significantly worse (t[304]=2.17, p=0.03; d=0.25; 95% CI [0.1, 2.7]) than the HC+ group (44.3+5.67). For RT, the HC- group (0.55+0.06) performed significantly slower (t[304]=-2.02, p=0.05; d=0.23; 95% CI [-0.03, -0.0003]) than the HC+ group (0.54+0.05).

Conclusion

Our results suggest HCs may influence ImPACT performance in female collegiate athletes. Clinicians must consider the role of HCs when interpreting ImPACT outcome scores.

The Test-Retest Reliability of a Clinically-Relevant Dual-Task Assessment in Healthy College Students

Purpose

The dual-task (DT) paradigm consists of concurrent administration of motor and cognitive tasks which may demonstrate improved measurement properties of the included tasks as compared to independent administration. Our study examined the test-retest reliability of a clinically-relevant DT assessment.

Methods

Our prospective cohort study included 60 (53.3% female) healthy, recreationally active college students (Age=20.5–1.34 years; Height=171.7–9.33 cm). Participants completed the Standardized Assessment of Concussion (SAC) and timed tandem gait (TTG) test concurrently for the DT assessment at two time points separated by a two-week test-retest interval. The SAC composite score (45 points) was calculated by summing the domain scores of immediate memory (30 points) which consisted of a 10-word list, concentration (5 points), and delayed recall (10 points). The TTG composite score was calculated by summing the mean time to complete the TTG during each SAC task (3 trials for immediate memory, up to 5 trials for the digits-backwards task, and one trial for the months in reverse order and delayed recall tasks). Mixed-model intraclass correlation coefficients (ICC[3,1]) with 95% confidence intervals were calculated to evaluate test-retest reliability between time points for the SAC and TTG composite scores.

Results

Mean SAC (39.4–3.80 vs. 39.6–3.49 points) and TTG (52.1–9.44 vs. 48.2–8.33 sec) composite scores were observed at time points 1 and 2, respectively. Moderate (ICC[3,1]=0.56 [0.26, 0.74]) and good (ICC[3,1]=0.88 [0.80, 0.93]) test-retest reliability were observed for the SAC and TTG composite scores, respectively.

Conclusion

Test-retest reliability for our DT assessment aligns with previously established values for independent administration of the SAC and TTG.