Within the past decade, electrical nerve stimulation has been introduced as a potential non-drug treatment for individuals suffering migraines or cluster headaches. The approach varies slightly between techniques, and depending on the method, can be invasive or non-invasive.
The FDA is slowly approving various devices for use in the US. Other techniques and devices have yet to achieve FDA approval but are being used in Europe. The primary issue for approval has been a lack of substantive testing and review by the research community. Many of the clinical trials have been small and not conducted as blinded studies nor controlled with placebo devices.
However, there is some evidence that neurostimulation is an effective treatment for migraine. We explain how each of the various methods works for stimulating the nerves and provide some information about who can use it and its side-effects, which appear to be few. Also, we delve into how nerve stimulation may relieve migraine pain as well as the benefits of neurostimulation.
Extremely far from being the type of electroshock therapy used in the mid-20th century for the treatment of mental illness, electrical nerve stimulation for migraine relief uses brief, low-voltage electrical or magnetic pulses to various areas of the head or neck. Where the stimulus is applied depends on the nerve bundle targeted.
The trigeminal nerve is the largest of the 12 cranial nerves and serves to transmit sensory information to the skin, sinuses, and mucous membranes of the face. It also stimulates the jaw muscles. External stimulation of the trigeminal nerve is a non-invasive treatment.
The supraorbital nerve is a branch of the trigeminal nerve and serves the eyes, frontal sinuses, and forehead, extending to the back of the scalp. Local anesthesia of this nerve is often used in facial surgery. Neurostimulation is non-invasive.
The vagus nerve is the longest and most complex of the 12 cranial nerves (remember, the trigeminal is the largest). Vagus is a Latin word that means “wandering.” The vagus nerve “wanders” throughout the body, transmitting and receiving impulses from a variety of tissues and organs. Vagal nerve stimulation is also non-invasive.
The sphenopalatine ganglion is a bundle of nerves under the nose that connects with the trigeminal nerve. These nerves control the lacrimal glands, which produce tears, as well as the inner lining of the nose and sinuses producing nasal discharge and congestion. Neurostimulation requires surgical implants.
The occipital nerves run from the top of the spinal cord to the scalp. The most common problem is inflammation that results in occipital neuralgia or pain in the back of the head and neck. Electrical leads implanted under the skin on the back of the head provide neurostimulation. In addition, a battery is implanted in the chest, hip, or belly to supply the electrical impulses.
External trigeminal nerve stimulation (and sometimes the supraorbital) is performed through a device with an electrode applied to the forehead. The stimulation creates a sedative effect that may reduce the number of migraine attacks. A small study found recipients had fewer days with migraine per month as well as fewer attacks. The headaches were less severe, and fewer migraine medications were required. Most of the patients were very satisfied or moderately satisfied.
Transcutaneous electrical nerve stimulation (TENS) is a method of stimulating the trigeminal nerve. The stimulus is applied at a specific level of microimpulses, set by a physician, targeting the upper branch of the trigeminal nerve or the supraorbital nerve. The occurrence of adverse events is low to non-existent.
A plastic band with the stimulation device is placed across the forehead over the trigeminal nerve. Pulsed, low-voltage electrical currents move across the skin to stimulate the peripheral nerves. A small study revealed several benefits:
1. A reduction in the number of monthly headache days.
2. A reduction in painkiller intake.
3. Higher patient satisfaction.
4. Few to no side-effects.
TENS can be used as a preventative and may be of particular help to patients at risk of medication overuse headache or in fragile migraine populations such as adolescents and the elderly.
Transcranial magnetic stimulation (TMS), or single-pulse TMS, sends targeted magnetic impulses to the occipital cortex at the back of the brain. Self-administered at home, the patient places the device on the back of the head for less than a minute to administer short magnetic pulses targeting layers of scalp, skull, meninges, cerebrospinal fluid, and superficial layers of the cortex. The pulse strength is pre-determined by a physician.
TMS modulates the electrical environment of neurons involved in migraine attacks, reducing the number and severity. A study showed reduced numbers of headache days and a decrease in the need for rescue medication.
Vagus nerve stimulation is another non-invasive treatment that can be self-administered. Initially approved for episodic cluster headaches, VNS may be used for migraine treatment as well. Patients hold the device against the side of the neck near the vagus nerve to deliver small amounts of electrical stimulation, which travels from the base of the skull to the abdomen.
The FDA approved VNS for migraine treatment in January 2018. A small study found 16% of attacks were pain-free after an hour, and almost 23% were pain-free after two hours of onset.
Sphenopalatine ganglion stimulation (SPG) requires the surgical implantation of a device in the upper gum of the mouth. Then a handheld device is placed against the cheek to deliver impulses to stop the pain.
Occipital nerve stimulation (ONS) is an invasive but reversible procedure in which electrical leads are implanted under the skin on the back of the neck. The leads connect to a wire and battery implanted in the chest, hip, or abdomen. The batter sends electrical signals to the occipital nerve at the back of the head just above the neck to relieve pain.
ONS is another promising treatment for migraines, but there have been mixed results for prevention. A small study revealed attack relief in about 14% of patients with the rest experiencing pain reduction.
Patients who have other health issues or can’t tolerate certain medications could benefit from nerve stimulation to treat their migraines. Others who are concerned about medication side-effects or overuse have another option to consider also. Patients who find it difficult to remember to take medications benefit as well.
The side effects are mild and tend to be limited to some dizziness, drowsiness, or slight discomfort that ends shortly after the treatment. However, if you wear a pacemaker or other implanted medical device, or a metal implant in the upper body, you may not be eligible. The treatment is also not recommended for patients diagnosed with epilepsy or have a history of seizures.
A lack of strict, broad-based clinical studies hampers the knowledge of the effectiveness of these treatments, but since there are few side-effects and some evidence of pain relief and migraine prevention, electrical nerve stimulation may be something to speak to your doctor about.