Comparing people with persisting post-concussion symptoms from an emergency department-based research sample with patients in a clinical rehabilitation sample: an explorative, retrospective analysis.

The two samples were collected at different times (2014-2015 vs 2019-2023), which may introduce bias due to changing public awareness or clinical practices. Data collection methods differed: the ED sample was assessed via telephone, while the clinical sample was assessed in person, potentially affecting symptom reporting. There were significant missing data for questionnaires in the ED sample (43% missing RPQ, RSA, and headache data), though analyses suggested those with missing data had similar symptom severity. The study is observational and cannot determine causality or whether referral practices select for the most severe cases versus the severity driving the referral.

The study was supported by the Liaison Committee between the Central Norway Regional Health Authority and the Norwegian University of Science and Technology. No commercial conflicts of interest were declared in the provided text.

Do not interpret the differences in injury severity criteria as evidence that the ED sample was healthier at baseline. The clinical rehabilitation sample included patients with minimal head injury who did not meet standard mild TBI criteria, yet they had worse outcomes, suggesting that standard injury definitions may miss those who develop disabling symptoms.