ObjectiveTo investigate the clinical features and changes of EEG in children with late onset epilepsy spasm. MethodsThe clinical data, treatment, follow-up and outcome of 13 patients with late-onset epilepsy spasms were analyzed retrospectively from June 2010 to August 2015 in Bo ai Hospital of Zhong Shan City.Affiliated Southern Medical University ResultsThirteen cases of children were enrolled in the group, including 9 males and 4 females, the onset of age were 1 year 3 months to 5 years 7 months, duration of treatment were 1 year 5 months to 4 years 8months.Seven cases of children had clear cause in 13 patients: 2 cases of viral encephalitis, 3 cases of HIE, 1 case of neonatal sepsis, ARDS, and 1 case of methylmalonic acid hyperchomocysteinemia.Six cases did not clear the cause.Spasm is still the main type of Seizures.Seven cases had seizures with partial origin.the most onset time were awake period and wake up for the time, and coexisted with other types of seizures.EEG in Epileptic seizures period was a broad range of high amplitude slow wave, slow bursts, complex or non-composite low amplitude fast wave, sometimes with the burst after the voltage attenuation of a few seconds, string or isolation occurs.Synchronous bilateral deltoid EMG monitoring showed bilateral or unilateral synchronous EMG 1 ~ 2s Bilateral or unilateral synchronous EMG outbreak1-2s.Intermittent EEG showed multifocal and extensive epileptic discharge, still sharp (spine) slow wave continuous release based.Treatment: All children underwent ACTH or methylprednisolone immunoregulation treatment, 3 cases underwent ketone diet therapy.At the same time choice valproic acid, topiramate, clonazepam, lamotrigine, levarabesilan and other anti-broad-spectrum antiepileptic drugs, according to the history.all children were taken in combination with the way.Prognosis: 13 patients'seizures reduced or controled after the end of the ACTH or methylprednisolone immunotherapy course.followed-up 3 to 12 months, the clinical attack control were failed 3 cases had relatively good prognosis, treated with Ketogenic diet (Lasted for 1 year 3 mothes~2 years 5 mothes), one case of attack control, mental improvement significantly, Another 2 cases, the numbers of episodes were reduced and the level of intelligence were significantly improved. ConclusionPerinatal factors and acquired brain injury are the most common cause of pathogenesis.Spasm as a major form of attack, and other forms of coexistence.EEG is not typical of high degree of performance.Simultaneous EMG monitoring shows bilateral or unilateral synchronous EMG outbreaks.The treatment of various antiepileptic drugs were ineffective.The vast majority of patients developed refractory epilepsy.Ketogenic diet treatment may be a relatively good choice.