Abstract Details Title Bilateral Parietal Pachygyria with Drug Refractory Epilepsy (DRE) Managed with Deep Brain Stimulation (DBS) of the Centromedian and Pulvinar Nucleus Topic Epilepsy/Clinical Neurophysiology (EEG) Presentation(s) P5 - Poster Session 5 (11:45 AM-12:45 PM) Poster/Presentation Number 10-006 Objective To report the seizure outcome following deep brain stimulation of the centromedian and pulvinar nuclei in a child with DRE resulting from bilateral parietal pachygyria. Background Pachygyria is a rare neuronal migrational disorder which often precludes any kind of resective surgery, due to widespread cortical involvement and proximity to eloquent brain areas. Design/Methods A 12-year-old girl with seizure frequency varying from multiple daily-weekly events refractory to adequate doses of 3 anti-seizure drugs. Her electroclinical features included dyscognitive events without aura, eye & head version to either side, and asymmetric tonic motor events. Chronic EEG telemetry revealed bilateral posterior head region IEDs and 21 events were recorded - 3 with left and 18 with right posterior head EEG onset. MRI revealed large symmetric pachygyria involving the bilateral parietal lobes. She underwent DBS lead implantation targeting both CMN and pulvinar nuclei bilaterally through a posterior approach. Stimulation began two weeks postoperatively and was titrated to 143 Hz, 90 µs, 3 mA, 1 min ON / 5 min OFF, cyclic mode. Results Preoperatively, she had 6–8 seizures per day, including tonic–clonic episodes and drop attacks. Seizures ceased postoperatively, with temporary relapse when stimulation was inadvertently deactivated supporting the response to neurostimulation. At 12-month follow-up, she remained seizure-free with improved functioning and no adverse effects. Cognitive status was significantly improved. Conclusions This case demonstrates the efficacy of a posterior-approach for combined targeting of the CMN + pulvinar in children with unresectable bilateral cortical malformations involving the parietal lobe. It further supports the use of this targeting and stimulation approach for biparietal seizures in general. Authors/Disclosures Srisai H. Rolla PRESENTER Miss Rolla has nothing to disclose.