In Reply: Anterior Nucleus of the Thalamus Deep Brain Stimulation With Concomitant Vagus Nerve Stimulation for Drug-Resistant Epilepsy.

Abstract

To the Editor: We are very grateful for Prof Balak's1 (the authors of Letter: Anterior Nucleus of the Thalamus Deep Brain Stimulation with Concomitant Vagus Nerve Stimulation for Drug-Resistant Epilepsy) personal comments related to our study about the anterior nucleus of the thalamus deep brain stimulation (ANT-DBS) with concomitant vagus nerve stimulation (VNS) for drug-resistant epilepsy.2 We also thank for his additional remarks with which we agree. As a matter of fact, we started ANT-DBS and concomitant VNS stimulation after ANT-DBS Food and Drug Administration approval according to previous research assessing the anatomic and functional relationships between the vagal afferents to the nucleus of the mammillotegmental tract and the ANT. Moreover, we also considered their negative modulation of hippocampal activity. Prof Balak1 rightly suggests that the central and peripheral stimulation we analyzed are not independent of each other but, rather, are complementary from a physiopathological point of view. In researching and writing our paper, we could only hope for such a supportive and insightful response. However, focusing on clinical data about the benefit of concomitant ANT-DBS and VNS therapy, our results indicate that the ANT-DBS effectiveness may be independent from ongoing VNS therapy because patients who underwent ANT-DBS without any VNS, those who received ANT-DBS with fully functioning VNS, and, finally, those who had ANT-DBS with disabled or removed VNS had no significant different seizure reduction percentage, even if our results were overall very positive. We also advise that the retrospective design and the relatively small population cohort may limit further understanding. Nevertheless, allowing the combined treatment we propose, we believe these features will become increasingly investigated, opening the door for further comments about this fascinating relationship.