Subacute encephalitis, i.e. subacute sclerosing total encephalitis, whose clinical manifestations are mainly neurological symptoms, can be categorized into four phases, ranging from mental disorders to the final end stage. 1. Behavioral disorders: also known as mental disorders, the main manifestations are memory loss, emotional instability, behavioral abnormalities, etc., which can last for weeks or even months. 2. Movement disorder stage: this stage mainly manifests severe progressive reduction of intelligence, accompanied by ataxia, myoclonus, visual impairment and so on. 3. Coma stage: patients will have ankyloglossia, positive Babinski’s sign, deafferentation, and finally develop coma. 4. Terminal stage: In this stage, patients have complete loss of cortical function and decreased muscle tone. Patients with subacute sclerosing total encephalitis should seek medical treatment promptly and follow the doctor’s instructions.