 Post-market, on-label, double-blind, randomized, prospective, interventional, tolerability and clinical outcomes study is designed to determine which VNS Therapy titration paradigm allows more patients to achieve a therapeutic dose within a specified time frame. Additionally, the study will collect data on the acute tolerability and clinical outcomes for patients with drug-resistant epilepsy treated with adjunctive VNS Therapy employing three different titration paradigms. 