Concussion Classification in a Multicenter Patient Cohort: The Updated ACRM Diagnostic Criteria and Concordance With Physician Impression of Injury.

The same physician provided both the general impression and the ACRM categorization, which may have led to contamination of the responses, although the final ACRM determination was withheld until after data collection. The study was conducted in specialty concussion clinics, so the high rate of positive diagnoses (96.9%) may not generalize to primary care or emergency department settings. Neuroimaging was not routinely used to determine the diagnostic category due to EMR limitations, and was only acquired in 35.8% of participants. Patients were assessed at a median of 23 days post-injury, which is outside the acute window (within 72 hours) where some criteria are most sensitive, potentially affecting the endorsement of certain clinical signs. The study relied on self-report for symptoms and mechanism, which can be influenced by recall bias and patient expectations.

Do not conclude that the ACRM criteria are more accurate than physician impression; the study shows they classify more patients as having mTBI, but does not prove these classifications are correct. The high rate of 'definite' diagnosis (85.6%) reflects the nature of a specialty concussion clinic population, not the general head-injury population.