Serum neuron-specific enolase level as a biomarker in differential diagnosis of seizure and syncope.

Patients who experience a single generalized tonic-clonic seizure or syncope may have similar clinical symptoms, which can cause difficulty in the differential diagnosis. The aim of this study was to examine whether serum neuron-specific enolase (NSE) has diagnostic relevance as a biochemical marker for these disorders. Serum NSE levels were analyzed following a loss of consciousness in patients who were diagnosed with a seizure (n = 52) and syncope (n = 42) compared with normal controls (n = 91). NSE was 14.97 ± 7.57 ng/dl for the seizure group, 10.15 ± 3.22 ng/dl for the syncope group, and 10.03 ± 1.28 ng/dl for the control group. The seizure group showed a significantly increased serum NSE (p < 0.05) compared to the syncope and control groups. By receiver operating characteristic (ROC) curve analysis, the cut-off value with the highest diagnostic accuracy was defined as 11.5 ng/ml with a sensitivity of 0.58 and specificity of 0.91. The NSE values of the syncope and control groups showed no significant differences. Syncope may not influence diffuse brain damage. Serum NSE measurement may be a helpful test for the identification and diagnosis of a seizure rather than syncope.