Combination of or Transition between Deep Brain Stimulation and Responsive Neurostimulation for the Treatment of Drug-Resistant Epilepsy

Abstract

<b><i>Introduction:</i></b> Neuromodulation is an important treatment modality for patients with drug-resistant epilepsy who are not candidates for resective or ablative procedures. However, randomized controlled trials and real-world studies reveal that a subset of patients will experience minimal reduction or even an increase in seizure frequency after neuromodulation. We describe our experience with patients who undergo a second intracranial neuromodulation procedure after unsatisfactory initial response to intracranial neuromodulation. <b><i>Methods:</i></b> We performed a retrospective chart review to identify all patients who had undergone deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) or responsive neurostimulation (RNS), followed by additional intracranial neuromodulatory procedures, with at least 12 months of follow-up. Demographic and clinical data, including seizure frequencies, were collected. <b><i>Results:</i></b> All patients had temporal lobe epilepsy. Six patients were treated with concurrent ANT DBS and temporal lobe RNS, and 3 patients transitioned between neuromodulation systems. Of the patients treated concurrently with ANT DBS and temporal lobe RNS, 5 of the 6 patients experienced additional reduction in seizure frequency after adding a second neuromodulation system. Of the patients who switched between neuromodulation modalities, all patients experienced further reduction in seizure frequency. <b><i>Conclusions:</i></b> For patients who do not experience adequate benefit from initial therapy with ANT DBS or temporal lobe RNS, the addition of a neuromodulation system or switching to a different form of neuromodulation may allow for additional reduction in seizure frequency. Larger studies will need to be performed to understand whether the use of multiple systems concurrently leads to improved clinical results in patients who are initially treatment resistant to neuromodulation.