Abstracts

Hypothalamic hamartoma (HH) is a well recognized etiology of refractory gelastic epilepsy often accompanied by precocious puberty and progressive mental deterioration. HH are congenital and characterized by a stable radiographic appearance. Hypothesis explaining gelastic seizures include interconnection of epileptic hamartomatous neurons with the limbic system. Surgery for HH is often unsuccessful with considerable associated risks related to its relative inaccessible and eloquent location. Epilepsy treatment modalities include medication, resection, stereotactic thermocoagulation, and radiosurgery. The latter two methods are safer than surgical resection yet offer only moderate success in controlling seizures. Surgery has been effective in some cases, though more often disappointing resulting in hypothalamic and mammillary body dysfunction without successful seizure control. We present our series of 5 patients (2 female) with HH. The average age at VNS implant = 26 y. Seizure onset occurred in young childhood usually before the first year of age. Seizures are gelastic with other manifestations. MRI documented relatively small lesions, 3 sessile and 2 pedunculated. All but one patient exhibited precocious puberty and mental developmental delay. Their seizure frequency was typically many per week. 2 patients had previous HH surgery. Mean follow up after surgery was 10 months. 4/5 patients showed significant improvement (at least 50% reduction in seizure frequency or at least 50% reduced seizure severity). None were seizure free. All tolerated VNS well without surgical complications. Vagal nerve stimulation (VNS)treatment for HH related epilepsy is an important substitute or adjunct for surgery and radiation. VNS should be considered first in these patients. VNS is effective in suppressing seizures with minimal risks or complications. VNS is an effective and safe treatment modality for achieving good seizure control, at least as good as resection or radiosurgery.