Hepatic encephalopathy mainly refers to severe acute or chronic liver disease that causes metabolic disorders of the central nervous system, and patients may present with impaired consciousness, behavioral changes, and coma. There are four levels of hepatic encephalopathy: Stage I, also known as prodromal stage, in which the patient may show mild personality and behavioral changes, no fluttering tremor on clinical examination, and no significant EEG abnormalities. Stage II is called pre-consciousness, and the patient may show mental confusion and abnormal behavior. Fluttering tremor, hyperactive tendon reflexes, increased muscle tone, and negative cone bundle signs are often present, while abnormal slow waves may appear on the EEG. In stage III, also known as the mute stage, the patient shows a state of mute but can be aroused. In stage III, the EEG may show significant abnormalities, and triphasic slow waves may appear. Stage IV is called coma, in which the patient loses consciousness and cannot be awakened, and fluttering tremor does not appear in deep coma.