Objective To explore the evaluation value of burden of amplitudes and epileptiform discharges score (BASED) in the efficacy of adrenocorticotropic hormone (ACTH) combined with magnesium sulfate therapy for infantile epileptic spasms syndrome (IESS). Methods Retrospective collection the clinical and EEG data of 124 patients admitted to the Dongguan Maternal and Child Health Care Hospital from 2015 to 2023, who were diagnosed with IESS and treated with ACTH combined with magnesium sulfate. According to whether there were epileptic seizures 14 days after ACTH treatment, the patients were divided into two groups: non seizure group (n=74 cases) and seizure group (n=50 cases). The BASED system was used to evaluate the relationship between changes in EEG before and after ACTH treatment and clinical efficacy in both groups. The analysis of electroencephalogram included: ① abnormally high amplitude background waves, ② >3 spike foci , ③ grouped multifocal spikes, ④ paroxysmal voltage attenuation. ResultThe control rate of ACTH combined with magnesium sulfate in the treatment of IESS was 59.7% (74/124), and there was no statistically significant difference in the control rate among children with different etiologies (P=0.09). The BASED score suggests that the overall response rate of electroencephalogram (EEG) in infants with epileptic spasm syndrome after treatment was 57.2%. The EEG remission rate in the seizure control group was 81% (60/74), while in the uncontrolled group was 22% (11/50). The EEG remission rate in the seizure control group was significantly higher than that in the uncontrolled group after treatment (P<0.001), and the EEG score was closely related to clinical efficacy (Spearman correlation coefficient rp=0.601, P<0.001). ConclusionThe BASED score is related to clinical efficacy, and it can provide a quantitative basis for evaluating the efficacy of ACTH combined with magnesium sulfate in the treatment of IESS.