Longitudinal Trajectories of Postconcussive Symptoms in Children With Mild Traumatic Brain Injuries and Their Relationship to Acute Clinical Status

OBJECTIVE. We examined whether mild traumatic brain injuries in children and adolescents, especially when associated with acute clinical features reflecting more severe injury, result in different postinjury trajectories of postconcussive symptoms compared with mild orthopedic injuries. PARTICIPANTS AND METHODS. Participants in this prospective and longitudinal cohort study were 8- to 15-year-old children, 186 with mild traumatic brain injuries and 99 with mild orthopedic injuries, who were recruited from consecutive admissions to emergency departments in 2 large children's hospitals. Parents rated current postconcussive symptoms within 3 weeks of injury and at 1, 3, and 12 months after injury. At the initial assessment, parents also provided retrospective ratings of preinjury symptoms, and children with mild traumatic brain injuries received MRI of the brain. Clinical features examined as predictors of postconcussive symptoms included loss of consciousness, Glasgow Coma Scale score below 15, other injuries, acute symptoms of concussion, and intracranial abnormalities on the MRI. RESULTS. Finite mixture modeling identified 4 longitudinal trajectories of postconcussive symptoms (ie, no postconcussive symptoms, moderate persistent postconcussive symptoms, high acute/resolved postconcussive symptoms, high acute/persistent postconcussive symptoms). The mild traumatic brain injuries and orthopedic injuries groups demonstrated a different distribution of trajectories. Children with mild traumatic brain injuries were more likely than those with orthopedic injuries to demonstrate high acute/resolved and high acute/persistent trajectories relative to the no postconcussive symptoms group. The 2 trajectories with high acute levels of postconcussive symptoms were especially likely among children with mild traumatic brain injuries whose acute clinical presentation reflected more severe injury. CONCLUSIONS. Mild traumatic brain injuries, particularly those that are more severe, are more likely than orthopedic injuries to result in transient or persistent increases in postconcussive symptoms in the first year after injury. Additional research is needed to elucidate the range of factors, both injury related and non–injury related, that place some children with mild traumatic brain injuries at risk for postconcussive symptoms.