Do injury characteristics predict the severity of acute neuropsychological deficits following sports-related concussion? A meta-analysis.

The utility of injury characteristics for predicting the severity of post-concussion outcomes remains equivocal. The purpose of this meta-analysis was to quantify the predictive relationship between these variables to inform classification of acute injury severity. Thirty-one empirical samples of concussed athletes, for which rates of loss of consciousness and/or amnesia were reported, were included in a meta-analysis evaluating acute outcomes following sports-related concussion. Outcome measures of interest were neuropsychological tests first administered 1-10 days post-injury. Loss of consciousness and anterograde amnesia significantly predicted more severe neuropsychological deficits within 10 days of concussion in studies using pre-injury baseline, but not control group, comparisons. Retrograde amnesia significantly predicted acute neuropsychological dysfunction (d = -1.03) irrespective of comparison group. Although small sample sizes require conservative interpretation and future replication, the evidence suggests that retrograde amnesia, rather than loss of consciousness, may be used to classify the acute severity of concussion.