This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Although mild traumatic brain injury (mTBI) is among the most common injuries in children, little systemic research has been done regarding the recovery process and long-term functional sequelae of children following mTBI, including the influence of genetic factors. Linking polymorphic alleles to neurocognitive outcome is one strategy to determine if certain genes contribute to recovery after mTBI. However, allelic polymorphism studies require well-defined and validated outcome measures and sample sizes appropriate for the frequency of alleles of interest. This protocol describes the Phase 1, the piloting phase, of a 4-phase, 6-year-multi-center collaborative research study between Children's National Medical Center, the Department of Education-Kaua'i Complex Area, University of Pittsburgh Medical Center, A.T. Still University and Dartmouth Hitchcock Medical Center. The aim of Phase 1, which has already been completed, was the initial development and adaptation of the three principal tests of the mTBI battery for the pediatric age range (5-18 years) - ImPACT, the BRIEF, and the N-back working memory measure. The specific aim of Phase 2 is the psychometric development of the tests with the mTBI battery including norming, test-retest reliability, and concurrent validity across the 5-18 year age range. The specific aim of Phase 3 is clinical validation, i.e., to establish the sensitivity and specificity of the mTBI battery to detect neruocognitive and behavioral changes in children with mTBI.