Developmental assessment-based surgical intervention for intractable epilepsies in infants and young children.

Purpose: To define the most appropriate time for surgery for medically intractable epilepsies in infants and young children. Methods: First we examined retrospectively the changes in developmental quotients (DQs) during the clinical course and the clinical factors affecting the DQ in 39 consecutive patients younger than 15 years, who underwent surgical treatment for intractable epilepsy. Second, we examined prospectively five new patients for early detection of developmental arrest or regression by periodic developmental assessments and whether this could lead to early surgical intervention, eventually resulting in minimal developmental defects. Results: Retrospective studies revealed that the DQ progressively decreased with age and that the reduction of DQ was related to continuing frequent seizures in many patients. The prospective studies demonstrated that periodic developmental assessments could detect the reduction of DQ at 5 months or later after onset of frequent seizures in three patients. In two other patients, operations were performed before reduction of DQs, and their postoperative DQ levels were normal. The postoperative recovery of DQ was complete in one patient whose operation was performed 3 months after reduction of DQ, whereas it was incomplete in two others whose operations were carried out at 12 and 14 months after reduction, respectively. Furthermore, three patients with norrnal developmental outcome had shorter periods between the onset of frequent seizures and the operation (≤7 months) than those of two patients with developmental delay (≥17 months). Conclusions: To minimize the developmental defects, periodic developmental assessments should be initiated when frequent seizures have occurred, and surgery should be considered as soon as possible when DQ reduction is recognized.