Mini Symptom Index Tool plus modified Vestibular-Ocular Motor Screening (mSIT Plus) for acute concussion identification: findings from the NCAA-DoD CARE Consortium

Objective: The purpose of this study was to (1) rigorously evaluate the Sport Concussion Assessment Tool (SCAT) 22-item symptom list and improve the area under the curve (AUC), sensitivity and specificity by creating the mini Symptom Index Tool (mSIT) and (2) identify the added utility of other examinations to include with the mSIT. Methods: Prospective cohort study, with nested subsets, of collegiate athletics and military service academies. 59 901 athletes and cadets were enrolled in the National Collegiate Athletic Association-Department of Defense Concussion Assessment Research and Education (CARE) Consortium; 5075 diagnosed with a concussion. These analyses used the SCAT symptom survey, Standardised Assessment of Concussion, modified Balance Error Scoring System, modified Vestibular/Ocular Motor Screening (mVOMS), Immediate Post-Concussion Assessment and Cognitive Testing, King-Devick, Clinical Reaction Time and numerous neuropsychological tests in concussed versus non-concussed individuals within 48 hours of injury. Results: Individual symptoms in the symptom survey demonstrated a variety of Cohen’s d effect sizes, the largest being pressure in head (d=2.59), do not feel right (d=2.51) and headache (d=2.85). The largest effect sizes of the examinations were Symptom Severity Score (d=2.09) and mVOMS (d=3.41). The proposed mSIT is the sum of the 7-point Likert symptom scores for headache, pressure in head, do not feel right, sensitivity to light, dizziness and sensitivity to noise (range 0–36). The AUC/sensitivity/specificity of SCAT symptom severity index was 0.88/85 %/76%, whereas mSIT was 0.94/87 %/88%. The only concussion test/examination which added utility to mSIT was mVOMS with an AUC/sensitivity/specificity of 0.94/88 %/92% when used in combination. The proposed clinical cut-off score is ≥2 for mSIT and ≥2 for mVOMS. All other examinations in CARE were non-additive in acute concussion identification. Conclusion: For a shorter concussion evaluation, the 6-question mSIT is recommended, improving the AUC from 0.88 to 0.94 with 2% better sensitivity and 12% better specificity compared with the 22-item SCAT Symptom Severity Score. Adding mVOMS further marginally enhances these metrics and can be completed within 2–3 min (mSIT Plus).