Post-concussion symptoms after mild traumatic brain injury: influence of demographic factors and injury severity in a 1-year cohort study

Purpose. To assess the prevalence and variation of post-concussion symptoms within the first year after mild traumatic brain injury (TBI), and explore the association between injury severity, demographic factors and symptoms. Methods. Prospective study of patients with mild TBI followed up at 3, 6 and 12 months (N = 96 included, n = 52 attending all follow-ups). Sociodemographic factors, injury mechanisms and impact of injury (Glasgow Coma Scale score, Abbreviated Injury Severity Score (AIS), Injury Severity Score) were recorded at inclusion. Symptoms were reported in the Rivermead Post-Concussion Symptoms Questionnaire (RPQ) at the follow-ups. The sumscore of all symptoms in RPQ was calculated for each subject. Scores were also calculated separately for the cognitive, physical and behavioural symptoms. Results. Twenty-nine subjects met the post-concussion syndrome criteria at 3 months, and 22 patients at 6 and 12 months. The cognitive symptoms were more prominent than the physical and behavioural symptoms. The cognitive and physical symptoms were associated with AIS for the head injury at 3 months, but not at 12 months. Considerable individual variability in the symptom pattern was found, and the subjects who attended only the 3-months follow-up reported a lower level of symptoms than those attending all follow-ups. Conclusions. Persistence of symptoms was a considerable problem even I year after the injury, with cognitive symptoms dominating. More severe AIS scores were associated with a higher level of cognitive and physical symptoms at 3 months, but not at later follow-ups. Strategies to prevent and treat these symptoms should be focussed in clinical practice.