Even a Mild Concussion Could Cause Long-Term Problems

Andrea Lauren Christman Schneider, J. Russell Huie, W. John Boscardin, Lindsay Nelson, Jason K. Barber, Kristine Yaffe, Ramon Diaz-Arrastia, Adam R. Ferguson, Joel Kramer, Sonia Jain, Nancy Temkin, Esther Yuh, Geoffrey T. Manley, Raquel C. Gardner
Female doctor holds a tablet with an image of a brain speaking with a seated male patient


Background and Objectives: The objectives of this study were to develop and establish concurrent validity of a clinically relevant definition of poor cognitive outcome 1 year after mild traumatic brain injury (mTBI), to compare baseline characteristics across cognitive outcome groups, and to determine whether poor 1-year cognitive outcome can be predicted by routinely available baseline clinical variables.

Methods: Prospective cohort study of 656 participants aged 17+ years presenting to Level 1 trauma centers within 24 hours of mTBI (Glasgow Coma Scale [GCS] 13-15) and 156 demographically similar healthy controls enrolled in the Transforming Research and Clinical Knowledge in TBI (TRACK-TBI) study. Poor 1-year cognitive outcome was defined as cognitive impairment (<9th percentile of normative data on ≥2 cognitive tests, cognitive decline (change score [1-year score minus best 2-week or 6-month score] exceeding the 90% reliable change index on ≥2 cognitive tests), or both. Associations of poor 1-year cognitive outcome with 1-year neurobehavioral outcomes were performed to establish concurrent validity. Baseline characteristics were compared across cognitive outcome groups and backward elimination logistic regression was used to build a prediction model.

Results: Mean age of mTBI participants was 40.2 years, 36.6% were female, 76.6% were white. Poor 1-year cognitive outcome was associated with worse 1-year functional outcome, more neurobehavioral symptoms, greater psychological distress, and lower satisfaction with life (all-p<0.05), establishing concurrent validity. At 1-year, 13.5% of participants with mTBI had a poor cognitive outcome versus 4.5% of controls, p=0.003. In univariable analyses, poor 1-year cognitive outcome was associated with non-white race, lower education, lower income, lack of health insurance, hyperglycemia, pre-injury depression, and greater injury severity (all-p<0.05). The final multivariable prediction model included education, health insurance, pre-injury depression, hyperglycemia, and Rotterdam CT Score>3 and achieved an AUC of 0.69 (95% CI=0.62-0.75) for the prediction of a poor 1-year cognitive outcome, with each variable associated with >2-fold increased odds of poor 1-year cognitive outcome.

Discussion: Poor 1-year cognitive outcome is common, affecting 13.5% of mTBI patients versus 4.5% of controls. These results highlight the need for better understanding of mechanisms underlying poor cognitive outcome after mTBI to inform interventions to optimize cognitive recovery.

Posted on BrainLine March 18, 2022. Reviewed March 18, 2022.