The Monarch external Trigeminal Nerve Stimulation (eTNS) System is a non-invasive medical device developed by physicians and researchers at the University of California, Los Angeles (UCLA) as an adjunctive treatment for epilepsy and depression. The Monarch is designed to provide safe and effective trigeminal nerve stimulation without the risks or complications of surgery. Clinical trials to date have demonstrated a robust effect of eTNS on patients with difficult-to-treat cases. For an overview of the peer-reviewed publications on eTNS, please see the links below.
The Monarch eTNS device is CE mark-approved and is available to patients and physicians in the European Union, Canada, and Australia. If you would like more information about incorporating the Monarch into your practice, please fill out the form provided and a NeuroSigma representative will contact you.
Mechanism of Action
The Monarch eTNS System is an innovative medical device from NeuroSigma, which provides non-invasive electrical stimulation to the V1 branch of the trigeminal nerve. The trigeminal nerve (also known as the 5th cranial nerve or Cranial Nerve V) is the largest cranial nerve and provides sensation to the face via three main branches (V1, V2, and V3). Due to its unique anatomy, the trigeminal nerve is effectively stimulated with non-invasive electrical signals applied to the forehead.
Once stimulated, signals from the trigeminal nerve enter the brain stem via the trigeminal nucleus. The trigeminal nucleus has connections to multiple other brainstem nuclei, such as the nucleus tractus solitarius (NTS), locus coeruleus (LC), the raphe nuclei, and spinal trigeminal nucleus. Studies of vagal nerve stimulation (VNS) have demonstrated that activation of the NTS and LC is critical for its antiepileptic effect. Once signals from the trigeminal enter the brain stem, they are directed to the thalamus, and on to higher cortical centers.
O15 Positron Emission Tomography (PET) studies of patients receiving eTNS have demonstrated acute changes in cerebral blood flow and metabolism. These studies show decreased blood flow in regions of the cortex known to be involved in the initiation and propagation of seizures, while simultaneously showing increased blood flow in brain regions shown to be hypometabolic in depression.
These data provide a framework for understanding eTNS where the activity of targeted brain regions is modified via non-invasive electrical stimulation of the trigeminal nerve. For a more detailed overview of the scientific literature published on eTNS to date, please visit our publications page.