EEG stabilization and cognitive gains after pulse steroid therapy in developmental and/or epileptic encephalopathy with spike-wave activation in sleep: A prospective cohort study.

BACKGROUND

Developmental and/or epileptic encephalopathy with spike-wave activation in sleep (D/EE-SWAS) is a rare paediatric epileptic encephalopathy characterized by marked activation of epileptiform discharges during non-REM sleep, leading to seizures and neurocognitive regression. Although corticosteroids are frequently used, prospective data on structured pulse steroid regimens and long-term neurocognitive outcomes from resource-limited settings are scarce.

OBJECTIVE

To characterize the clinical, electroencephalographic, and neuropsychological profile of children with D/EE-SWAS and to evaluate the electroclinical and cognitive impact of a six-month pulse intravenous methylprednisolone (IVMP) regimen.

METHODS

In this prospective cohort study, 29 children with D/EE-SWAS were enrolled from two tertiary centers in India and followed for two years. Monthly IVMP (25 mg/kg/day for 3 days) was administered for six months, with stable anti-seizure medications. Serial overnight EEGs assessed spike-wave index (SWI) and spike dipole stability quotient (SQ), a qualitative marker of cortical source coherence. Neuropsychological evaluations covering attention, memory, executive, visuospatial, and adaptive functioning were conducted at baseline and at two years. Repeated-measures ANOVA, paired t-tests and correlation statistics were used for statistical analysis.

RESULTS

Pulse IVMP therapy resulted in a significant and sustained reduction in seizure frequency and SWI over 24 months (p < 0.001), with a progressive increase in SQ. Improvement in SWI and seizure control occurred early, while SQ improved significantly only after 12 months. Idiopathic D/EE-SWAS showed durable electroclinical improvement, whereas symptomatic cases demonstrated transient gains with partial relapse at two years. Early EEG response was prognostic- higher SWI and lower SQ at six months predicted higher seizure frequency at 24 months. Neuropsychological outcomes revealed significant improvements in attention and verbal learning overall, with meaningful domain-specific cognitive recovery predominantly confined to the idiopathic group.

CONCLUSION

A structured six-month pulse IVMP regimen was associated with early spike suppression and delayed network stabilisation. Etiology significantly influenced long-term EEG stability and cognitive recovery. Early dipole stabilization may serve as a prognostic biomarker for long-term seizure control beyond spike burden alone.