Concussion Guidelines Step 1: Systematic Review of Prevalent Indicators, a special supplement of Neurosurgery, is available online with free full text access.
It is authored by Nancy Carney, PhD; Jamshid Ghajar, MD, PhD; Andy Jagoda, MD; Steven Bedrick, PhD; Cynthia Davis-O’Reilly, BSc; Hugo du Coudray, PhD; Dallas Hack, MD; Nora Helfand; Amy Huddleston, MPA; Tracie Nettleton, MS; and Silvana Riggio, MD.
Because of the lack of sufficient objective data from strong studies, concussion remains undefined. There was sufficient reliable information to compile the following:
The most prevalent indicators of concussion, observed in alert individuals (Glascow Coma Scale of 13 to 15) after a force to the head are:
- Observed and documented disorientation or confusion immediately after the event
- Impaired balance within 1 day after injury
- Slower reaction time within 2 days after injury
- Impaired verbal learning and memory within 2 days after injury
Key Findings – Among the studies included in the review:
- Loss of Consciousness (LOC) ranged from 1% to 14.3%
- Posttraumatic amnesia (PTA) ranged from 2% to 29.7%
- Retrograde amnesia ranged from 7.4% to 53.3%
- Disorientation/confusion ranged from 18% to 44.7%
- The prevalence of balance deficits ranged from 23.8% to 36.5% within 24 hours of injury and decreased to 19.2% to 24% by day 2.
- The prevalence of slowed reaction time ranged from 41.7% to 71.4% within 24 hours of injury.
- Findings indicated that in the majority of cases, cognitive deficits resolved within one week.
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