Serum brain‐derived neurotrophic factor levels in epilepsy

Background and purpose To clarify the utility of serum brain‐derived neurotrophic factor ( BDNF ) as a biomarker for epilepsy diagnosis and severity. Methods Serum BDNF levels in 135 consecutive people with epilepsy meeting our criteria were assessed. Controls were 34 healthy individuals who over 12 months or longer had no complaints or signs of a neurological disorder. Serum BDNF concentrations were measured using L uminex technology. Results Gender, but not age, was found to be a significant factor related to serum BDNF levels in controls and people with epilepsy. Serum BDNF levels in people with epilepsy (mean 8798.5, SE 321.5 pg/ml) were not different from those of controls (mean 8919.5, SE 709.0 pg/ml). A multiple linear regression analysis, however, suggests that seizure frequency ( P < 0.001) and epilepsy duration ( P = 0.025) negatively correlate with serum BDNF levels independently of other factors. When BDNF cut‐off values of 6260 pg/ml were used, the sensitivity for distinguishing people with daily or more frequent seizures from those with fewer seizures was 80% and specificity was 90%. Conclusions It seems that the concentration of BDNF in serum is associated with disease severity in people with epilepsy and may be a helpful marker for severity.