Effect of Transcranial Direct Current Stimulation on Postoperative Delirium in Elderly Patients

To evaluate the efficacy of transcranial direct current stimulation (tDCS) in reducing the incidence of postoperative delirium (POD) in elderly patients undergoing hip fracture surgery. This single-center, double-blind, randomized controlled trial will enroll participants aged 65 years and older, scheduled for elective hip surgery under spinal anesthesia. Participants will be randomly assigned to either the active-tDCS group or the sham-tDCS group. The active-tDCS group will receive two sessions: one pre-surgery and one post-surgery, with electrodes positioned over the left dorsolateral prefrontal cortex and the right supraorbital area. Each session includes 15-second ramp-up phase at the start, 20 minutes simulation with 2 mA current and 15-second ramp-down phase at the end. The sham-tDCS group will receive two sham procedures with no actual current delivered. Functional brain activity will be monitored before and after each session or sham procedure to assess changes in cortical activation and connectivity using functional near-infrared spectroscopy (fNIRS). The primary outcome measure will be the incidence of POD, assessed using the 3-Minute Diagnostic Interview for Confusion Assessment Method (3D-CAM). Secondary outcomes include the severity of delirium, postoperative pain, anxiety, depression, cognitive function, and sleep quality.