Postoperative neurocognitive disorders (PND) are serious and common complications after surgery, especially in elderly patients. These disorders can affect cognitive functions for years, deteriorating quality of life and increasing hospital stays and medical costs. Diagnosing PND is challenging due to their varied manifestations, such as memory and attention problems, and the lack of standardized criteria and biomarkers. One well-studied form of PND is postoperative delirium (POD). According to the ICD-10, POD is an organic cerebral syndrome characterized by disturbances in consciousness, attention, perception, and other cognitive functions. Researchers suggest that POD development involves a combination of predisposing and precipitating factors. Electroencephalography (EEG) has been used in anesthesiology to assess anesthesia depth and intraoperative awareness. Modern EEG analysis methods, like spectral analysis, offer new ways to evaluate patients' neurophysiological states. Studies show that EEG monitoring can predict complications such as intraoperative stroke and delirium, particularly in cardiothoracic and neurosurgical operations. The relationship between EEG patterns and POD is not well understood. Specific EEG patterns may indicate the risk of POD, aiding in the identification of risk factors and prevention methods. This could help anesthesiologists and surgeons optimize their approaches, reducing the risk of cognitive complications.