Criteria used to define mild traumatic brain injury (mTBI) in the included studies
| Criteria | Number of studies (n, %) |
| Glasgow Coma Scale (GCS) | |
| 13–15 | 23* (63.8) |
| 14–15 | 7 (19.4) |
| 15 | 1 (2.8) |
| NR | 5† (13.9) |
| Loss of consciousness (LOC) | |
| <10 min | 4 (11.1) |
| <15 min | 5 (13.9) |
| <30 min | 9* (25) |
| No duration | 8† (22.2) |
| No use of LOC | 10 (27.8) |
| Post-traumatic amnesia (PTA) | |
| <15 min | 1 (2.8) |
| <30 min | 0 (0) |
| <60 min | 4* (11.1) |
| <24 hours | 3 (8.3) |
| No duration | 7† (19.4) |
| No use of PTA | 21 (58.3) |
| Initial altered mental state | |
| Yes | 3 (8.3) |
| Absence of focal neurology deficit | |
| Yes | 14 (38.9) |
| Triaged to non-contrast head CT using the (ACEP/CDC) evidence-based joint practice guideline | 3† (8.3) |
| Use of the American Congress of Rehabilitation Medicine definition (1993) | 6 (16.7) |
| Use of European Federation of Neurological Societies definition (2002) | 1* (2.8) |
*Heidari et al 90 90 used the following mTBI definition: (1) a GCS score of 13–14; (2) a GCS score of 15 with LOC <30 min, PTA <1 hour; or (3) a GCS score of 15 without LOC or PTA.
†Korley et al 28 28 presented three different cohorts with different inclusion criteria. Only the mTBI definition of the case cohort is presented in the table.
‡ACEP, American College of Emergency Physicians; CDC, Centers for Disease Control and Prevention.