A comparison of long-term postconcussive symptoms between university students with and without a history of mild traumatic brain injury or orthopedic injury.

Mild traumatic brain injury (mild TBI) is often associated with postconcussive symptoms such as headache, memory problems, and irritability. However, high rates of similar symptoms in groups without a history of TBI raise questions about the clinical validity of the postconcussive syndrome. This study was conducted to address these issues through systematic examination of symptoms reported by those with and without a history of mild TBI or orthopedic injury. Responses to the Postconcussion Syndrome Checklist (PCSC), demographic information, and medical history were collected via online questionnaire from 3027 non-referred university students (2280 without a history of mild TBI or orthopedic injury, 491 with a history of orthopedic injury, and 256 with post-acute mild TBI). Although the mild TBI group reported higher mean levels of symptoms, confirmatory factor analyses demonstrated that symptoms clustered into parallel cognitive, somatic, affective, and sensory factors in all three groups. Despite modestly higher mean symptoms among those with a history of mild TBI, symptom clusters did not differ from non-TBI groups. These findings cast doubts about the clinical validity of the "postconcussive syndrome" and raise questions about pathways by which mild TBI and other factors may influence the expression of chronic symptoms.