Transcutaneous electrical stimulation of auricular branch of the vagus nerve effectively and rapidly modulates the EEG patterns in patients with possible electrographic status epilepticus.

Abstract

Invasive vagal nerve stimulation (iVNS) is a known treatment approach for patients with refractory epilepsy. Transcutaneous auricular vagus nerve stimulation (tVNS) was developed to overcome the side effects and surgical complications of iVNS. tVNS is proven beneficial in refractory epilepsy. The effectiveness of tVNS, however, has never been studied in patients with Status Epilepticus. In this study, we explored the effect of tVNS in three patients with possible electrographic status epilepticus. To compare the EEG pattern before, during and after tVNS in three patients with possible electrographic status epilepticus. Three consecutive patients with possible electrographic status epilepticus were included after due consenting process. In addition to the standard care, tVNS was applied on the left ear over the cymba concha in two sessions, 6 h apart, with each session for 45 min. Continuous EEG monitoring was performed as standard of care and the findings before, during and after tVNS were documented. The duration of status epilepticus at the time of inclusion of Patients 1, 2, and 3 was 6 weeks, 7 days, and 5 days respectively. All were in coma and on multiple antiseizure medications. Patient 1 and 3 were on anesthetic infusions. Before stimulation, one patient had burst suppression pattern and two had generalized periodic discharges at 1 Hz frequency. We observed a significant reduction/resolution of ongoing EEG patterns in all three patients during the stimulation. The abnormal patterns re-emerged approximately 20 min post cessation of tVNS. No stimulation-related side effects were detected. There was no change in clinical status, but all three patients had severe underlying conditions. Transcutaneous auricular Vagus Nerve Stimulation (tVNS) is a potential noninvasive adjuvant therapy that can modulate EEG patterns in patients with Status epilepticus. Larger studies in early SE are needed to assess its clinical benefits.