This prospective, longitudinal cohort study investigated cognitive functioning acutely and up to 6 months after pediatric mild traumatic brain injury (mTBI) relative to orthopedic injury (OI).

Children age 8–17 years with acute (≤48 hours) mTBI or OI were consecutively recruited from five pediatric Emergency Departments. Acute Predicting and Preventing Postconcussive Problems in Pediatrics (5P) clinical risk scores were calculated. Children completed three CNS Vital Signs computerized cognitive battery subtests acutely (≤48 hours) and at 7 days, 3 months, and 6 months post-injury, and performance validity testing at all post-acute assessments. Generalized least squares models were fitted for Reaction Time, Visual Memory, and Executive Function standard scores.

For children (N = 841; 556 mTBI/285 OI; 12.45 ± 2.41 years; 57.91% male; 68.13% White) with valid performance validity and cognitive test scores, Reaction Time was lower after mTBI relative to OI for older (but not younger) children; differences declined in magnitude from acutely (d = −1.11) to 6 months (d = −0.21). Visual Memory was mildly lower across time after mTBI (d = −0.20). Odds of clinically impaired (standard score < 80) Reaction Time were higher acutely and post-acutely after mTBI for older children (OR = 51.33 to 8.01), but did not differ by group for Visual Memory or Executive Function. 5P clinical risk scores did not predict cognitive scores after mTBI.

Pediatric mTBI negatively impacts cognition, especially for reaction time, ≤48 hours post-injury and among adolescents. Early cognitive dysfunction persists up to 6 months after mTBI in some children.