Integrate Impact with Advanced Brain Imaging to Evaluate the Effects of Sports-Related Concussion (SRC) on High School Athletes: Analysis of a Longitudinal Study

Background: Our study sought to address whether there exists a time trend and group difference (Sports-related Concussion (SRC) vs. Orthopedic injury (OI)) in the change of Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) scores after the injury. Additionally, our study investigated if brain function alternations persist for concussed adolescent athletes who were cleared to return to play. Study group: SRC high school athletes were recruited from the Memorial Hermann Ironman Sports Medicine Institute (MHISMI) Concussion Clinic within three days after SRC (n=29). High school athletes with orthopedic injury were recruited from the MHISMI Orthopedic Section (n=21). The OI group is a control group that had comparable age, sex, and socioeconomic status with SRC group. Methods: Generalized estimating equation model (GEE) for continuous outcomes was used in this longitudinal data analysis. Unstructured correlation structure was used to account for within-individual correlations. Independent variables included group, study time point as a categorical variable, group by time interaction, and baseline ImPACT PCS score. The two-sample t-tests were used to compare the differences in outcome measures between the two groups. The effect sizes were estimated using the Cohen’s d, where d=0.2, 0.5, and 0.8 correspond to small, medium and large effects respectively. Results: There was a significant main effect of time and group for PCS total score change from baseline, with more severe scores for the SRC group compared to the OI group. Specifically, the SRC group had worse physical and cognitive symptoms compared to the OI group following SRC. The SRC showed a significant higher AD or ADC in the genu of the corpus callosum, left uncinate fasciculus, left and right whole frontal than the OI group. Conclusions: Our results provide longitudinal evidence of recovery of post-concussion symptoms for concussed athletes. There existed a time trend in ImPACT total scores in the concussion group, which increased rapidly after concussion and then decline gradually back to normal. Importantly, increased ADC or AD was shown to have the potential as objective biomarkers for SRC, which can aid physicians to determine whether the concussed athlete could be cleared to return to play