Persistent status epilepticus is a common neurological emergency, of which non-convulsive status epilepticus accounts for about 1/3, and it is relatively difficult to diagnose because it contains a group of different clinical syndromes. In China, the understanding of NCSE needs to be improved, and a unified and standardized treatment plan needs to be formulated. In view of this, all members of the EEG and Epilepsy Group of the Neurology Branch of the Chinese Medical Association organized a questionnaire survey on the treatment of NCSE by experts in epilepsy-related fields nationwide, summarized the results of the questionnaire, and finally formed this consensus after repeated discussions and modifications. I. Definition and epidemiology of NCSE At present, there is no unified definition of NCSE. In recent years, Shorvon proposed that “NCSE refers to persistent epileptiform discharges on the electroencephalogram, resulting in clinical non-convulsive seizures”. Others believe that the definition of NCSE should include clinical manifestations (often including impairment of consciousness), EEG abnormalities during seizures, and response to treatment. For the duration of seizures, most experts suggest that a duration of 30 min or more is defined as NCSE. There are four main clinical types of NCSE: aphasic seizure duration (ASE), simple partial seizure duration (SPSE), complex partial seizure duration (CPSE), and seizure duration in coma, including mild seizure duration (SSE). Epidemiological data show that the incidence of NCSE is 2 to 20/100,000. II. Symptoms Simple partial seizure sustained status epilepticus (SPSE) symptoms are mainly subjective and usually nonspecific to the patient, such as auditory abnormalities, aphasia, sensory abnormalities, taste or smell changes, psychiatric symptoms, autonomic symptoms and behavioral changes. Unlike CPSE, patients with SPSE do not show altered ability to engage with the environment and have normal consciousness. The EEG shows focal spike waves or spike-slow complex waves of different frequencies. However, because it is more limited, the scalp EEG sometimes fails to show these abnormalities, and the diagnosis must then depend on clinical symptoms. Complex partial seizure continuity (CPSE) is always associated with altered consciousness, usually in the form of altered ability to engage with the environment. Patients present with blurred consciousness and behavioral abnormalities, such as oral or manual automatisms. The epileptiform discharges in CPSE can be more widespread than in SPSE and are usually bilateral, which can explain the diversity of clinical symptoms in CPSE. Persistent status epilepticus with mild seizures (SSE) develops from GCSE and is caused by inadequate or untreated treatment of the latter. It manifests as epileptiform discharges on the EEG but no or only intermittent motor seizures clinically. The inconsistency between significant epileptiform discharges on the EEG and the absence of clinically significant motor seizures is characteristic. The EEG shows generalized or unilateral spike-wave or spike-slow wave emission. The vast majority of idiopathic GCSEs do not progress to refractory, and SSE, despite being an NCSE, has a poor prognosis and is considered to be the most severe clinical stage of GCSE. III. Diagnosis The diagnosis of NCSE should be made in conjunction with the patient’s past medical history, clinical symptoms, and EEG. Sometimes, the improvement of clinical symptoms and EEG after benzodiazepine treatment may also contribute to the diagnosis of NCSE. clinical symptoms of NCSE are often nonspecific, so it is difficult to make a diagnosis based on symptoms alone. However, the presence of a precipitating cause of epilepsy, severe impairment of consciousness, and spontaneous eye movements (e.g., nystagmus) are suggestive of an association with NCSE. A previous history of epilepsy is more supportive of the diagnosis of NCSE, but the absence of a history of epilepsy cannot be completely excluded, as many patients present with NCSE as the first manifestation of epilepsy. the diagnosis of NCSE also requires the exclusion of other diagnoses. These include acute stroke, inflammation (e.g., limbic lobe or neocortical inflammation), infection (e.g., herpes simplex virus encephalitis), primary or metastatic brain tumors in nonmotor areas, and delirium, trance, hallucinations, and psychogenic pseudo-continuity due to psychiatric factors. The possibility of NCSE should be considered in patients with clinically relevant symptoms to avoid missing the diagnosis; the value of long-range EEG cannot be overestimated, but the presence of abnormal EEG is more supportive of NCSE diagnosis. IV. Treatment The treatment of NCSE varies depending on the clinical type and etiology. Given that NCSE causes fewer acute or chronic systemic complications compared with GCSE, except for the diagnostic persistence of minor seizures, a relatively conservative treatment compared with GCSE is recommended (only for the application of anesthetic drugs), but does not imply a delay in the initial treatment of NCSE. If the diagnosis of NCSE is established, non-benzodiazepines (AEDS) should be given as soon as possible. The longer the duration of NCSE before treatment, the more difficult it is to terminate the episode. Given that some drugs such as lorazepam and fosphenytoin are not approved for marketing in China. Therefore, in this consensus, intravenous benzodiazepines are preferred for patients with ASE (seizures with inappropriate application of non-AEDS), SPSE, CPSE & SSE. If the seizure is not terminated, the same dose of benzodiazepines may be repeated. If the seizure remains uncontrolled, 1 AED may be given intravenously or intramuscularly, or another benzodiazepine may be given intravenously. Thereafter, the options are an intravenous benzodiazepine + 1 AED, and a second intravenous or intramuscular AED. intravenous narcotics are only considered in patients with SSE. For ASE patients whose episodes are caused by inappropriate application of AEDS, the preferred treatment is to discontinue these AEDS.