412 CONCLUSION: As concussion management requires serial testing, high test-retest reliability is needed. Although ICC 2,k values were similar between time intervals, a higher number of domains in the 1-year interval met the reliability standards required for clinical care (ICC>0.70) and no domains displayed low levels of reliability (ICC<0.40). Should clinicians choose to complete multiple healthy baselines, a 1-year interval between assessments is recommended. Supported by the NOCSAE Domain 4-Month Interval (n=38) 1-Year Interval (n=31) ICC2.k SEM ICC2.k SEM Neurocognitive Index 0.678 5.469 0.949 4.451 Composite Memory 0.508 9.446 0.742 8.243 Verbal Memory 0.506 11.582 0.633 12.238 Visual Memory 0.598 7.996 0.586 9.411 Psychomotor Speed 0.715 6.930 0.661 6.566 Reaction Time 0.756 5.933 0.809 5.729 Complex Attention 0.659 12.093 0.971 14.247 Cognitive Flexibility 0.719 8.207 0.539 8.295 Processing Speed 0.599 8.833 0.527 9.105 Executive Function 0.489 15.074 0.569 7.632 Reasoning 0.621 9.318 0.732 7.763 Simple Attention 0.338 16.859 0.971 47.889 Motor Speed 0.808 6.093 0.662 5.647 1478 Board #153 June 1 9:00 AM - 10:30 AM Impact of Diagnosed Sleep Disorder on Baseline Concussion Assessments in Collegiate Athletes Jamie McAllister-Deitrick 1 , Alicia Sufrinko 2 , Anthony P. Kontos 2 . 1 Coastal Carolina University, Conway, SC. 2 University of Pittsburgh, Pittsburgh, PA. Email: jdeitrick@coastal.edu (No relationships reported) Research suggests at least 27% of college students are at risk for at least one sleep disorder. Adolescents with sleep-related symptoms and reduced sleep duration perform worse on baseline neurocognitive testing, although this effect size is small and samples have not included older or collegiate-level athletes. Previous research has not taken into consideration the effects of previously diagnosed sleep disorders on performance of preinjury baseline assessment. PURPOSE: The purpose of the current study was to compare athletes with and without a history of diagnosed sleep disorders on commonly used baseline concussion assessments. METHODS: All participants completed baseline testing including: the Balance Error Scoring System (BESS), Brief Symptom Inventory (BSI), Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), Post-Concussion Symptom Score (PCSS), Standardized Assessment of Concussion (SAC) and Vestibular/Ocular Motor Screening (VOMS). A total of 632 NCAA student-athletes participated in the study including 316 with previously diagnosed sleep disorders and 316 with no history of sleep disorder, matched for age, sex, sport, concussion history and race. Both groups were 19.87 years old (SD = 1.36), consisted of 176 males (55.7%), with 119 athletes (37.7%) previously having sustained a concussion, and represented a multitude of sports. RESULTS: A series of one-way ANOVAs with Bonferroni corrections revealed significant differences between groups on BESS (F(1, 535) = 4.02, p = .045), BSI somatization (F(1,623) = 11.41, p < .01), BSI depression (F(1, 623) = 13.59, p < .01), BSI anxiety (F(1, 623) = 20.97, p < .01), BSI global severity index (F(1, 623), p < .01) and PCSS (F(1, 396) = 22.86, p < .01). Specifically, the diagnosed sleep disorder group scored worse on the BESS and reported higher BSI and PCSS symptoms. No differences were noted between groups on VOMS, ImPACT neurocognitive measures, and SAC. CONCLUSION: Collegiate student-athletes with sleep disorders may have elevated affective and concussion symptoms at baseline that could affect interpretation of post- injury impairment and symptoms. Clinicians should assess diagnosed sleep disorders during pre-participation sport physicals and consider them when interpreting post-injury assessments. 1479 Board #154 June 1 9:00 AM - 10:30 AM Quantitative Electroencephalography in the Evaluation of Concussive Head Injury in Adolescents Julie Wilson, Ariel Kiyomi Daoud, Erin Moix Grieb, Pamela Wilson, Gerald Clayton. Children’s Hospital Colorado, Aurora, CO. Email: julie.wilson@childrenscolorado.org (No relationships reported) PURPOSE: Reliable quantitative methods are needed to evaluate concussion-related morbidity. Electroencephalographic event-related potentials (ERPs) are being investigated for documentation of post-brain injury changes in the acute and chronic setting. Previous studies demonstrated attenuation of ERPs in the setting of concussion; however, no investigation of an exclusively adolescent population has been performed. The p300 ERP is related to decision-making, specifically evaluation and categorization of external stimuli. This study evaluated reliability and utility of p300 ERP in adolescent concussion. Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.