BDNF serum concentrations & disease severity, as measured by MMSE, separated by diagnostic group. A) bvFTD, B) SemD, C) AD, D) MCI. The four diagnostic groups were parameterized and entered as separate predictors into a general linear model to determine if diagnostic group membership predicted BDNF concentrations controlling for age and gender. Disease severity did not significantly predict BDNF serum concentrations within any diagnostic group.