Abstracts

RATIONALE: The epilepsy syndrome associated with hypothalamic hamartomas can be medically intractable and not amenable to resective surgery. This syndrome may also be associated with difficult to manage, aggressive or self-injurious behaviors. The vagus nerve stimulator (VNS) approved in 1997 as an adjunctive treatment for intractable partial seizures has proven to be helpful in many seizure types and for many epilepsy syndromes. We report on 4 patients with intractable seizures due to a hypothalamic hamartoma who had a VNS implanted for seizure control. METHODS: 4 patients with hypothalamic hamartomas (3 males, 1 female, ages 11-24 years) were implanted with the VNS. All patients had the VNS turned on within 24 hours of implant and were then ramped up (duty cycle output of 1.5 mamps, on-time of 30 sec, off-time of 5 min, magnet output of 1.75 mamps, pulse width 500 msec, pulse frequency of 30 Hz) over several weeks. The duty cycle was held constant for at least 2 mos, then adjusted based on individual responses. Seizure counts and quality of life (QL) issues were documented by a caregiver at subsequent follow-up visits. Follow-up ranged from 1 year (1 patient) to greater than 2 years (3 patients). RESULTS: 3 of 4 patients had a greater than 50% reduction in total seizure counts and/or >50% reduction in specific seizure type (GTC, CPS, atypical absence and drop). These 3 patients also had overall improvement in alertness and daily QL. Anticonvulsant medications were significantly reduced in 1 patient. One patient had no reduction in seizure activity and no improvement in QL in spite of changes in duty cycle. The VNS was ultimately turned off in this patient after 1 year due to lack of efficacy and perceived side effects. No serious adverse events were reported with any of the 4 patients. The details of each patients' response will be shown. CONCLUSIONS: The VNS is an effective treatment for patients with seizures and hypothalamic hamartomas.