Most drugs used in general anesthesia work on various receptors in the human brain, causing unconsciousness, loss of memory, and loss of reflection of the autonomic nervous system. After the anesthesia, baseline physiological function will be attained by administration of some reversal drugs or as the time goes by. In this process, various side effects may occur.

Emergence delirium (ED) is a representative behavioral disturbance after general anesthesia in children and that can cause several problems during the recovery period. Previous EEG studies reported that this phenomenon is related to hyperexcitation of the brain, and occurrence of epileptiform discharges during anesthesia induction may indicate an increased vulnerability for the development of a functional brain disorder in these children.

However, to the best of our knowledge, there is no studies concern evaluating quantitative EEG parameters for prediction of this postoperative negative behavior in children.

Inclusion Criteria:

• Children aged between 2 and 10 years of American Society of Anesthesiologists physical status (ASA PS) I or II who are planned to receive surgery under general anesthesia

Exclusion Criteria:

• If the guardian and the subject are difficult to evaluate normally due to language barriers/language disorders/delay or autistic disorder
• with developmental delay, neurological disorders or psychiatric diseases associated with symptoms of agitation, anxiety, attention deficit, sleep disturbances, etc
• refusal of consent
• Recent history (within a month) of received general anesthesia or surgery
• presence of congenital or other genetic conditions thought to influence brain development

This study collects subjects from a tertiary university hospital.