Special points	VNS is effective in reducing seizure frequency in patients with chronic refractory epilepsy, with more than 40 % of implanted patients achieving a 50 % or greater reduction in seizure frequency [97], and often leads to improved quality of life, possibly due to reduction in AED load [43–47, 98, 99].
Complications	Dysphonia, dysphagia, throat pain/dysesthesias.
Cost	Expensive over a short term but highly cost-effective longitudinally.