Short-term EEG Outcomes in Children With Developmental and/or Epileptic Encephalopathy With Spike and Wave Activation in Sleep (DEE-SWAS) Treated With High-Dose Diazepam

<b>Objectives:</b> This retrospective study enrolled consecutive children aged 2-18 years with developmental and/or epileptic encephalopathy with continuous spike and wave during sleep (D)EE-SWAS who received oral high-dose diazepam therapy. Their clinical, electroencephalographic (EEG), and radiologic data were reviewed and summarized. <b>Results:</b> Thirty-five eligible patients were identified. The mean age at EEG diagnosis of (D)EE-SWAS was 6 years. Focal seizures (57.1%) were most commonly noted at the time of diagnosis. A definite language regression was reported in 10 patients (28.6%). The etiologies included structural (34.3%), genetic (22.9%), and unknown (42.9%). The mean spike-wave index at the time of high-dose diazepam initiation was 88.9% (standard deviation 11%). Sixteen patients (45.7%) showed ≥50% reduction in spike-wave index following the test doses of high-dose diazepam. Most patients tolerated the therapy well. Nonstructural etiology was associated with a good EEG response (β = 2.61, <i>P</i> = .008). The mean duration of follow-up after EEG diagnosis was 6.1 years. All patients were seizure free at last follow-up except one. Persisting SWAS (spike-wave index > 50%) at last follow-up was noted in 12 patients (34.3%). <b>Conclusions:</b> This single-center small retrospective study showed that nearly half of the patients showed ≥50% reduction in spike-wave index following the test doses of high-dose diazepam in patients with (D)EE-SWAS.