Anterior thalamic deep brain stimulation in epilepsy patients refractory to vagus nerve stimulation: A single center observational study

Is thalamic deep brain stimulation synergistic with vagus nerve stimulation in drug‐resistant genetic generalized epilepsy?

“…13 Some patients with generalized epilepsies have demonstrated benefits from VNS despite their exclusion during initial regulatory trials in patients with focal epilepsies. 11 Our patient with drug-resistant GGE had elements of idiopathic and structural metabolic origin. While absences and GTC seizures were presumed to be genetically mediated she failed more than 10 adequate trials of ASMs partially responding to VNS therapy but with ongoing monthly GTC seizures.…”

“…15 It is possible that the therapeutic effects of stimulating ANT and the vagus nerve are synergistic to exert activation on different aspects of the therapeutic network in patients with generalized epilepsies associated with different anatomical trajectories. 11 In patients with ANT-DBS for the treatment of DRE, the generation of cortical activation has helped predict the clinical efficacy of stimulation with successful targeting and programming, providing insights into its mechanism of action. 14 VNS-ANT DBS combination may provide an indirect afferent network of neuronal activation via the vagus nerve and direct efferent network inhibition to provide a synergistic form of polyneuromodulation.…”

“…A retrospective study reported equivalent seizure reduction rates in 12 patients with simultaneous VNS and DBS stimulation, compared to 21 patients treated by DBS only, either with or without a history of prior VNS treatment suggesting ANT‐DBS may offer clinical improvement in patients with partial benefit as well as in those who previously failed VNS therapy 13 . Some patients with generalized epilepsies have demonstrated benefits from VNS despite their exclusion during initial regulatory trials in patients with focal epilepsies 11 . Our patient with drug‐resistant GGE had elements of idiopathic and structural metabolic origin.…”

“…10 Seizure reduction with VNS improves over time, with approximately 50%-60% of patients achieving a 50% reduction in seizure frequency after 2-4 years of VNS therapy, with seizure freedom occurring in less than 5%-8% of cases. 10,11 In addition, only 16% are seizure-free from ANT DBS for 6 months or more at 5 years. 12 Despite a secondary and different method of neuromodulation when ANT-DBS is combined with VNS prolonged seizure freedom is not anticipated.…”

“…The findings are relevant since most patients treated with neuromodulation do not achieve complete and sustained seizure freedom 10 . Seizure reduction with VNS improves over time, with approximately 50%–60% of patients achieving a 50% reduction in seizure frequency after 2–4 years of VNS therapy, with seizure freedom occurring in less than 5%–8% of cases 10,11 . In addition, only 16% are seizure‐free from ANT DBS for 6 months or more at 5 years 12 .…”