Prognostic value of neuron-specific enolase (NSE) for prediction of post-concussion symptoms following a mild traumatic brain injury: a systematic review

Background: This systematic review aimed to determine the prognostic value of neuron-specific enolase (NSE) to predict post-concussion symptoms following mild traumatic brain injury (TBI). Methods: Seven databases were searched for studies evaluating the association between NSE levels and post-concussion symptoms assessed ≥ 3 months (persistent) or ≥ 7 days < 3 months (early) after mild TBI. Two researchers independently screened studies for inclusion, extracted data and appraised quality using the Quality in Prognostic Studies (QUIPS) tool. Results: The search strategy yielded a total of 23,298 citations from which 8 cohorts presented in 10 studies were included. Studies included between 45 and 141 patients (total 608 patients). The outcomes most frequently assessed were post-concussion syndrome (PCS, 12 assessments) and neuropsychological performance deficits (10 assessments). No association was found between an elevated NSE serum level and PCS. Only one study reported a statistically significant association between a higher NSE serum level and alteration of at least three cognitive domains at 2 weeks but this association was no longer significant at 6 weeks. Overall, risk of bias of the included studies was considered moderate. Conclusions: Early NSE serum level is not a strong independent predictor of post-concussion symptoms following mild TBI.