Type II Cortical Dysplasia in Dominant Frontal Lobe presenting as Gelastic Epilepsy (P6.295)

BACKGROUND: Gelastic seizures are episodes of unprovoked and uncontrolled laughter associated with ictal or interictal EEG changes. They are mostly associated with hypothalamic hamartomas. Among the extra-diencephalic foci, temporal lobe focus seems to be most common, even though frontal and parietal onset have also been reported. OBSERVATION: 6-year old boy with history of mild developmental delay and sensory integration disorder suffered from 10-15 seconds episodes of unprovoked laughter, preceded by throat clearing, followed by 5-10 seconds of post-ictal confusion. Neurologic exam, CT and MRI were unremarkable. On video EEG, rhythmic left fronto-temporal paroxysmal fast activity was detected, rapidly spreading bilaterally. Multiple anti-seizure medication trials were attempted: Oxcarbazepine (up to 20 mg/kg/day), then Valproate (30 mg/kg/d), Levetiracitam (80 mg/kg/d), Lacosamide (10 mg/kg/d), Topiramate (10 mg/kg/d) and Clobazam (10 mg BID). Despite the aggressive pharmacotherapy, the seizures persisted up to 40-60 per day. Concern was raised for a possible immunologic etiology, leading to CSF studies which were unremarkable except for oligoclonal bands. He received IV methyl-prednisone (1g/day for 5 days) followed by 5 cycles of plasma exchange. An ictal-SPECT was conducted to look for a specific epileptogenic focus, and demonstrated increased signal in the left frontal cortex. The MRI was reviewed, confirming the presence of a likely focus in the left frontal lobe, consistent with type-II cortical dysplasia. He underwent sub-dural grid placement and intracranial EEG recording. The epileptogenic focus, broca’s area and other eloquent areas of cortex were demarcated. After resection of the frontal lobe epileptogenic focus, the patient remained seizure-free, without speech or other neurological complications. Histopathology was consistent with type-II cortical dysplasia. RELEVANCE: Gelastic epilepsy often goes unrecognized; additionally subtle cortical dysplasias can be difficult to identify on MRI. Cortical dysplasias can be associated with drug-resistant focal epilepsy, but surgical resection of the epileptogenic focus has shown promising results. Disclosure: Dr. Peeters has nothing to disclose. Dr. Dubey has nothing to disclose. Dr. Thodeson has nothing to disclose. Dr. Dowling has received personal compensation for activities with Educational Testing Consultants, Inc. Dr. Sirsi has nothing to disclose. Dr. Arnold has nothing to disclose. Dr. Said has received personal compensation for activities with Novartis as a speaker.