Abstracts

Tuberous sclerosis complex (TSC) is a neurocutaneous syndrome which affects multiple organs. Neurologic manifestations are present in greater than 50% of patients and include epilepsy and mental retardation. Approximately 80% of patients with TSC and seizures are refractory to standard antiepileptic medications. Surgical treatment is beneficial if the seizure onset can localized; however, often patients are found to have a multifocal onset of seizures. In these patients were more than one seizure focus is present, Vagus Nerve Stimulation (VNS) offers another treatment option. Fourteen patients were identified out of the TSC clinic at Cincinnati Children[apos]s Hospital who had undergone a VNS implant. All patients had a confirmed diagnosis of TSC by either genetic analysis or meeting required major and minor diagnostic criteria. A phase one pre-surgical evaluation was completed on all patients. Patients had failed on average 10 medications. Seizure types included simple partial, complex partial and secondarily generalized. Seizure logs were maintained prior to and following VNS implant. VNS programming followed a protocol involving increases in output current followed by adjustments of duty cycle. Side effects and other aspects quality of life were documented at each visit as reported by the patient and family. Data was collected and analyzed at six and twelve months. Fourteen patients were identified. Age of seizure onset ranged from birth to five years. Age at time of implant ranged from 3-12 years. All patients were described as developmentally delayed. There were 12 patients with at least six month follow-up and seven patients with at least one year follow-up. Seizures were divided into simple/complex partial and secondarily generalized. The average seizure reduction for simple/complex partial seizures was 56% at 6 months and 60% at 12 months. For secondarily generalized seizures the average seizure reduction was 22% at both 6 and 12 months. A 50% reduction in simple/complex partial seizures was seen in 67% of patients at 6 months and 57% at 12 months. A 75% reduction in simple/complex partial seizures was seen in 56% of patients at six months and 43% at 12 months. All patients reported improvements in quality of life such as decreased post-ictal period and increased alertness. Side effects were mild and included coughing and voice change. In our patients with TSC and intractable epilepsy who were not surgical candidates, VNS offered an alternative treatment option that was effective in decreasing both simple/complex partial seizures and secondarily generalized seizures. All patients experienced other positive effects following VNS implant. No serious side effects were seen. It is important to note that the VNS appeared to be more successful in decreasing simple/complex partial seizures than secondarily generalized seizures in our population of patients with TSC.