Electrophysiological patterns and therapeutic outcomes in DEE ‐ SWAS : A cohort study from a tertiary pediatric neurology center

OBJECTIVE: This study aimed to evaluate the clinical, electrophysiological, and radiological characteristics of pediatric patients diagnosed with developmental and epileptic encephalopathy with spike-wave activation during sleep (DEE-SWAS) and to identify factors associated with prognosis. METHODS: Twenty-five pediatric patients with a spike-wave index (SWI) ≥50% and a minimum of 2 years of follow-up were analyzed in this retrospective cohort study. Clinical data, electroencephalogram (EEG) findings, and neuroimaging results were assessed, and their relationship with residual neurological or electrophysiological abnormalities was examined. RESULTS: The patients' mean age was 9.4 ± 2.97 years, with a mean age at seizure onset of 6.6 ± 2.32 years. Etiologically, 60% of patients were unknown, and 40% were known. The baseline mean SWI was 67.1%, decreasing to 13.8% by the 24th month. Patients with residual findings had significantly higher SWI values at months 3, 6, and 24 (p = .04, p = .006, and p = .01, respectively). Additionally, these patients exhibited lower EEG background frequency and higher amplitude during wakefulness (p = .026 and p = .001). Abnormal neurological examination was significantly associated with the presence of residual findings (p = .02). SIGNIFICANCE: Early and substantial reduction in SWI is associated with better prognosis. Persistent high SWI and abnormal background EEG activity may serve as predictors of long-term neurological impairment. These findings underscored the importance of early identification of high-risk patients and personalized treatment strategies in the management of DEE-SWAS.