SCOTTSDALE, Ariz. -- Noninvasive neuromodulation devices are safe, well tolerated, and clinically approved for migraine and episodic cluster headache, a researcher said here.
In recent years, the FDA has cleared single-pulse transcranial magnetic stimulation (Cerena, Spring TMS), noninvasive vagus nerve stimulation (gammaCORE), and external trigeminal nerve stimulation devices (Cefaly) to treat primary headache disorders, said Amaal Starling, MD, of the Mayo Clinic facility here, in a plenary session at the .
Anatomical targets in neuromodulation range from central to peripheral, Starling noted. In general, noninvasive neuromodulation devices have fewer risks and are preferred over invasive ones. Currently available devices may be effective for both prevention and acute treatment: "We're starting to see a blurring of acute and preventive lines," she said.
Single-pulse transcranial magnetic stimulation (sTMS), which is approved for acute and preventive treatment for migraine, demonstrated rates over sham treatment and is effective for , Starling stated. "It is dependent on the concept of electromagnetic induction, where electrical current is delivered across resistive layers of the scalp, skull, meninges, cerebrospinal fluid, and into the superficial layers of the cortex," she explained. "When it gets into that area, it modulates the electrical environment."
By altering the electrical environment of cortical neurons, sTMS inhibits cortical spreading depression and alters neuronal excitability, Starling added. Transcranial magnetic stimulation has been used safely for decades to treat several neurologic and psychiatric disorders without significant side effects, but it is contraindicated in patients with epilepsy or who have pacemakers or implants made of metal or other conductive materials, she noted.
Noninvasive vagus nerve stimulation (nVNS) is approved for the acute treatment of episodic cluster headache attacks and migraine. In a , nVNS significantly increased the probability of having mild pain or being pain-free 2 hours after using the device. "There's still a lot more we need to learn about the targets for vagal nerve stimulation," Starling observed. But in preclinical models, nVNS has been shown to reduce pain-induced activation of neurons in the trigeminal nucleus caudalis and reduce trigeminal allodynia. There also may be potential anti-inflammatory effects from vagus nerve stimulation, she noted.
Noninvasive vagus nerve stimulation appears to be safe, with no serious adverse events, including no cardiovascular events, but patients with pacemakers or metal implants should not use it, as well as patients with carotid atherosclerotic disease. Patients with a history of cervical vagotomy, or who have significant hyper/hypotension or brady/tachycardia also should not use the device.
(eTNS) -- also called transcutaneous supraorbital neurostimulation (sTNS) -- is approved for acute and . It transmits electrical impulses through an adhesive electrode to stimulate supraorbital nerves. Supraorbital neurostimulation likely inhibits nociceptive transmission in small pain-transmitting fibers, resulting in modulation of nociceptive activity in the trigeminal ganglion.
No serious adverse events have been reported with eTNS, and mild adverse events include sleepiness, fatigue, insomnia, headache, local pain, and local skin allergy from the adhesive electrode. The device should not be used by patients with pacemakers, intracardiac lines, or metal implants or other conductive materials in the head.
Neuromodulation may be an option for many patients with medical comorbidities and polypharmacy, as well as for patients who want a simpler or non-drug treatment approach, but access can be limiting factor. Most devices have to be rented at a cost of several hundred dollars a month, and not all are covered by commercial insurance.
Many new neuromodulation devices are under development, Starling noted: "There are so many different ways we can peripherally access the central brain process of primary headache disorders."
Disclosures
Starling disclosed relationships with Alder, Amgen, Eli Lilly & Company, and eNeura.
Primary Source
AHS Scottsdale Headache Symposium
Starling A "Neuromodulation" SHS 2018.