Restoration of Normal Brain Connectivity With Deep Brain Stimulation for Drug-Resistant Epilepsy in a Pediatric Patient.

Epilepsy is recognized as a network disorder. For drug-resistant epilepsy (DRE) that is not amenable to focal resection, deep brain stimulation (DBS) can modulate large-scale networks and improve seizure control. A 16‑year‑old patient with long‑standing DRE underwent hippocampal DBS. Following posterior lead migration, the patient developed a sustained clinical benefit, with seizure frequency decreasing from 12 to 16 daily events to occasional, non-disabling episodes occurring less than once per month - an evolution from Engel Class IVA to Engel Class IC in the Engel Epilepsy Surgery Outcome Classification. After a generator replacement in 2019, resting‑state functional magnetic resonance imaging (rs‑fMRI) was acquired with the stimulator off at discharge, and subsequently at one week and one month, and compared with a healthy control. The rs‑fMRI off‑stimulation imaging showed noticeable hypoconnectivity within the default mode network (DMN). At one week of stimulation, DMN connectivity remained reduced. One month after reactivation, DMN connectivity resembled the control pattern, paralleling the improvement in seizure control. This single‑case observation suggests that DBS may reversibly modulate intrinsic brain networks in DRE, with a time-dependent restoration of DMN connectivity. Although preliminary and exploratory in nature, these findings motivate prospective studies to confirm mechanisms and the durability of network normalization with DBS.