Longitudinal developmental trajectories after epilepsy surgery in early childhood: A biphasic developmental hypothesis

Objective To evaluate the longitudinal impact of epilepsy surgery on developmental trajectories in young children by comparing developmental rate (DR) during the early postoperative and later follow‐up periods. Methods This single‐center retrospective observational study included 90 children who underwent their first epilepsy surgery before 72 months of age. Development was assessed using the Kinder Infant Developmental Scale (KIDS). To reduce the influence of chronological age, DR was calculated as the change in developmental age divided by the observation period. DR during the first postoperative year was defined as early‐phase DR, and DR from the 1‐year postoperative assessment to the final developmental assessment was defined as late‐phase DR. Developmental trajectories were compared between these two phases. Results Early‐phase DR was significantly higher than late‐phase DR in the overall cohort (median .22 vs .08, p < .001). This pattern was consistently observed regardless of epilepsy syndrome, surgical procedure, etiology, preoperative developmental quotient, epilepsy duration, or seizure recurrence during the first 12 postoperative months. Higher early‐phase DR was associated with better preoperative developmental status and postoperative electroencephalographic improvement at 1 year. Significance Our findings suggest that postoperative developmental trajectories following epilepsy surgery in early childhood may be biphasic, characterized by an initial increase in developmental rate during the first postoperative year, followed by a slower but sustained increase thereafter. This early postoperative acceleration may partly reflect relief from epileptic encephalopathic effects, whereas later developmental attainment appears to be more strongly constrained by the underlying etiology and the child's intrinsic developmental potential. These findings should be interpreted as hypothesis generating and require validation using additional objective developmental measures.