Investigation of vagus nerve stimulation for treatment of intractable epilepsy

Objective To investigate the effectiveness of vagus nerve stimulation (VNS) therapy in intractable epilepsy. Methods VNS were performed in twenty - one patients. The generator was turned on 2 weeks after operation. Stimulation parameters were adjusted gradually. The output currents adjusted from 0.25 mA, and less than 3.0 mA. Stimulative time was 30 s ON and 5 min OFF, the frequency was from 20to 30 Hz, and the pulse width was from 250 μs to 1000 μs. The patients were followed up so as to analysis the effectiveness. Results After4 - 16 months of intermittent stimulation of the vagus nerve, grade Ⅰ in 3 patients, grade Ⅱ in 7 patients, grade Ⅲ in 9 patients and grade Ⅴ in 2 patients. Among them, seizure frequency was reduced over 50% occurred in 10 patients. Conclusion VNS can reduce seizure frequency,improve the quality of life in patients with intractable epilepsy, and it is a minimal invasive surgery with few side effects. Key words: Epilepsy; Vagus nerve stimulation; Prognosis