Longitudinal Trajectories of Post-Concussive Symptoms Following Mild Traumatic Brain Injury.

Background: Individuals recovering from mild traumatic brain injury (TBI) represent a heterogenous population that requires distinct treatment approaches. Identification of recovery trajectories improves our ability to understand the natural history of mild TBI recovery and develop targeted interventions.

Objective: To utilize group-based trajectory modeling (GBTM) to identify distinct patterns of symptom recovery following mild TBI in the first 6 months after mild TBI.

Methods: This study is comprised of 253 adults who presented to the emergency department with mild TBI and completed assessments for six-months post-injury. Patients were recruited for the prospective observational cohort study, HeadSMART. The primary outcome measure was the Rivermead Postconcussion Symptom Questionnaire. GBTM was used to identify longitudinal trajectories of recovery following mild TBI using Rivermead scores at baseline, one, three, and six months following diagnosis.

Results: Findings identified four distinct trajectories of symptom recovery follwing mild TBI including 9% of participants who were categorized with minimal acute symptoms that decreased over time, 45% with mild acute symptoms that decreased over time, 33% with relatively higher acute symptoms that decreased over time, and 13% with relatively higher acute symptoms that increased over time.

Conclusions: GBTM identified four distinct trajectories of recovery following mild TBI and GBTM may be useful for research interventions that can alter recovery trajectories.