The aim of this study in elderly hip fracture patients was twofold: (1) to compare changes before and after surgery of S100B and NSE levels in serum in patients with and without postoperative delirium, and to investigate the difference in serum levels before, during and after delirium; (2) to study the serum levels of S100B and NSE in different subtypes of delirium. This evidence concerns the gene ENO2 and delirium.