Context: Computerized neuropsychological testing is commonly used in the assessment and management of sport-related concussion. Even though computerized testing is widespread, psychometric evidence for test-retest reliability is somewhat limited. Additional evidence for test-retest reliability is needed to optimize clinical decision making after concussion. Objective: To document test-retest reliability for a commercially available computerized neuropsychological test battery (ImPACT) using 2 different clinically relevant time intervals. Design: Cross-sectional study. Setting: Two research laboratories. Patients or Other Participants: Group 1 (n = 46) consisted of 25 men and 21 women (age = 22.4 ± 1.89 years). Group 2 (n = 45) consisted of 17 men and 28 women (age = 20.9 ± 1.72 years). Intervention(s): Both groups completed ImPACT forms 1, 2, and 3, which were delivered sequentially either at 1-week intervals (group 1) or at baseline, day 45, and day 50 (group 2). Group 2 also completed the Green Word Memory Test (WMT) as a measure of effort. Main Outcome Measures: Intraclass correlation coefficients (ICCs) were calculated for the composite scores of ImPACT between time points. Repeated-measures analysis of variance was used to evaluate changes in ImPACT and WMT results over time. Results: The ICC values for group 1 ranged from 0.26 to 0.88 for the 4 ImPACT composite scores. The ICC values for group 2 ranged from 0.37 to 0.76. In group 1, ImPACT classified 37.0% and 46.0% of healthy participants as impaired at time points 2 and 3, respectively. In group 2, ImPACT classified 22.2% and 28.9% of healthy participants as impaired at time points 2 and 3, respectively. Conclusions: We found variable test-retest reliability for ImPACT metrics. Visual motor speed and reaction time demonstrated greater reliability than verbal and visual memory. Our current data support a multifaceted approach to concussion assessment using clinical examinations, symptom reports, cognitive testing, and balance assessment.

Context A battery of clinical measures of neurocognition, balance and symptoms has been recommended for the management of sport concussion (SC) but is based on variable evidence. Objective To examine the sensitivity and specificity of a battery of tests to assess SC in college athletes. Design Cross-sectional. Setting Research laboratory. Patients or other participants Division 1 athletes diagnosed with a SC (n=40) who were 20.2±1.60 years of age and 180.5±11.12 cm tall and healthy athletes (n=40) who were 19.0±0.93 years of age and 179.1±11.39 cm tall were enrolled. Intervention(s) Participants were administered Immediate Postconcussion Assessment and Cognitive Test (ImPACT), the Sensory Organization Test (SOT) and the Revised Head Injury Scale (HIS-r) prior to and up to 24 h following injury between the 2004 and 2014 sport seasons. Sensitivity and specificity were calculated using predictive discriminant analyses (PDA) and clinical interpretation guidelines. Main outcome measures Outcome measures included baseline and postinjury ImPACT, SOT and HIS-r composite scores. Results Using PDA, each clinical measure's sensitivity ranged from 55.0% to 77.5% and specificity ranged from 52.5% to 100%. The test battery possessed a sensitivity and specificity of 80.0% and 100%, respectively. Using clinical interpretation guidelines, sensitivity ranged from 55% to 97.5% individually, and 100% when combined. Conclusions Our results support a multidimensional approach to assess SC in college athletes which correctly identified 80–100% of concussed participants as injured. When each test was evaluated separately, up to 47.5% of our sample was misclassified. Caution is warranted when using singular measures to manage SC.

Context: To ensure that concussed athletes return to play safely, we need better methods of measuring concussion severity and monitoring concussion resolution. Objective: To develop a dual-task model that assesses postural stability and cognitive processing in concussed athletes. Design: Repeated measures study. Setting: University laboratory. Patients or Other Participants: Twenty healthy, college-aged students (10 men, 10 women; age = 20 ± 1.86 years, height = 173 ± 4.10 cm, mass = 71.83 + 35.77 kg). Intervention(s): Participants were tested individually in 2 sessions separated by 2 days. In one session, a balance task and a cognitive task were performed separately. In the other session, the balance and cognitive tasks were performed concurrently. The balance task consisted of 6 conditions of the Sensory Organization Test performed on the NeuroCom Smart Balance Master. The cognitive task consisted of an auditory switch task (3 trials per condition, 60 seconds per trial). Main Outcome Measure(s): For the balance test, scores for each Sensory Organization Test condition; the visual, vestibular, somatosensory, and visual-conflict subscores; and the composite balance score were calculated. For the cognitive task, response time and accuracy were measured. Results: Balance improved during 2 dual-task conditions: fixed support and fixed visual reference (t₁₈ = −2.34, P < .05) and fixed support and sway visual reference (t₁₈ = −2.72, P = .014). Participants' response times were longer (F_1,18 = 67.77, P < .001, η² = 0.79) and choice errors were more numerous under dual-task conditions than under single-task conditions (F_1,18 = 5.58, P = .03, η² = 0.24). However, differences were observed only during category-switch trials. Conclusions: Balance was either maintained or improved under dual-task conditions. Thus, postural control took priority over cognitive processing when the tasks were performed concurrently. Furthermore, dual-task conditions can isolate specific mental processes that may be useful for evaluating concussed individuals.

Context: Knowledge about the specific environmental and practice risks to participants in American intercollegiate football during preseason practices is limited. Identifying risks may mitigate occurrences of exertional heat illness (EHI). Objective: To evaluate the associations among preseason practice day, session number, and wet bulb globe temperature (WBGT) and the incidence of EHI. Design: Descriptive epidemiology study. Setting: Sixty colleges and universities representing 5 geographic regions of the United States. Patients or Other Participants: National Collegiate Athletic Association football players. Main Outcome Measure(s): Data related to preseason practice day, session number, and WBGT. We measured WBGT every 15 minutes during the practice sessions and used the mean WBGT from each session in the analysis. We recorded the incidence of EHIs and calculated the athlete-exposures (AEs). Results: A total of 553 EHI cases and 365 810 AEs were reported for an overall EHI rate of 1.52/1000 AEs (95% confidence interval [CI] = 1.42, 1.68). Approximately 74% (n = 407) of the reported EHI cases were exertional heat cramps (incidence rate = 1.14/1000 AEs; 95% CI = 1.03, 1.25), and about 26% (n = 146) were a combination of exertional heat syncope and heat exhaustion (incidence rate = 0.40/1000 AEs; 95% CI = 0.35, 0.48). The highest rate of EHI occurred during the first 14 days of the preseason period, and the greatest risk was during the first 7 days. The risk of EHI increased substantially when the WBGT was 82.0°F (27.8°C) or greater. Conclusions: We found an increased rate of EHI during the first 14 days of practice, especially during the first 7 days. When the WBGT was greater than 82.0°F (27.8°C), the rate of EHI increased. Sports medicine personnel should take all necessary preventive measures to reduce the EHI risk during the first 14 days of practice and when the environmental conditions are greater than 82.0°F (27.8°C) WBGT.