Mildly abnormal EEG refers to the previous classification of EEG as mild, moderate, or severely abnormal EEG. EEG abnormalities may manifest as abnormalities in EEG waveform, amplitude, and frequency. It is characterized by an increase in fast waves, a slowing of the normal rhythm of the EEG, as well as an increase in the probability of slow waves by more than 20% and a change in amplitude by more than 20%. This classification is artificially defined according to the epileptiform discharges in the EEG at the time of monitoring, which may not be completely related to the actual condition, and needs to be judged in conjunction with the patient’s clinical symptoms. The number of discharges also does not necessarily reflect the severity of epilepsy, and is not comparable between different patients. In conclusion, mild EEG abnormalities can only serve as a certain reference value, and timely examination in regular hospitals to clarify the diagnosis.