Abstract: Objective To investigate the clinical effect of vagus nerve stimulation in the treatment of refractory epilepsy and its impact on cognitive function. 
Methods A total of 12 patients with intractable epilepsy treated by vagus nerve stimulation were selected. According to the McHugh rating scale, the therapeutic effect was evaluated at 1 month before operation and at 3, 6, 9 and 12 months after operation. Raven′s reasoning test was used to evaluate IQ, and cognitive function was assessed by mini-mental state examination(MMSE), and the Beijing version of the Montreal cognitive assessment(MoCA). 
Results With the extension of treatment time, the frequency of attack gradually decreased, and the difference was statistically significant(P＜0.05). The incidence of remission more than 50% was 33.3% in 3 months, 66.7% in 6 months, 75.0% in 9 months and 83.33% in 12 months. IQ, MMSE score and Beijing version of MoCA score at 12 months after surgery were higher than those at 1 month before surgery, and the differences were statistically significant(P＜0.05). 
Conclusion Vagal nerve stimulation is safe and effective in the treatment of refractory epilepsy. It can not only reduce the frequency of epileptic seizures, but also improve the IQ level and cognitive ability of epileptic patients.

Key words: drug resistant epilepsy, vagus nerve stimulation, cognition