The vagus nerve is a major neural pathway extending from the brainstem through the neck, chest, and abdomen, connecting the brain to numerous internal organs. Its broad influence on bodily functions and potential role in managing certain types of headaches are areas of growing interest.
The Vagus Nerve’s Role in Headache Disorders
The vagus nerve, also known as the tenth cranial nerve, originates in the brainstem and extends throughout the body. Approximately 80% of its fibers transmit sensory information from organs back to the brain (afferent), while the remaining 20% send signals from the brain to control bodily functions.
This nerve is a principal component of the parasympathetic nervous system, governing the body’s “rest and digest” functions. The vagus nerve contributes to pain modulation and anti-inflammatory processes by activating the cholinergic anti-inflammatory pathway, which releases acetylcholine to inhibit pro-inflammatory cytokines.
The vagus nerve also influences pain signaling pathways by modulating activity in specific brainstem regions. It can suppress activity in the trigeminal nucleus caudalis, a brainstem area involved in processing pain signals, particularly those associated with headaches. Connections between vagal nerve fibers and the trigeminal nerve further suggest its involvement in headache mechanisms.
“Vagus nerve headache” is not a formal medical diagnosis. Instead, the nerve’s multifaceted functions are implicated in primary headache disorders, such as migraine and cluster headaches. Targeting the vagus nerve has become a focus in developing new treatment strategies for these conditions.
Device-Based Vagus Nerve Stimulation
Medical devices offer two primary approaches for stimulating the vagus nerve: invasive and non-invasive methods. Invasive Vagus Nerve Stimulation (VNS) involves a surgical procedure where a device, similar to a pacemaker, is implanted under the skin in the chest. A wire from this device is threaded under the skin and connected to the left vagus nerve in the neck.
This implanted device delivers mild electrical pulses to the vagus nerve, which then sends signals to the brain. Invasive VNS is primarily approved for conditions like refractory epilepsy and treatment-resistant depression. While its use for severe headaches has been explored, its application for primary headache disorders is less common compared to non-invasive options.
Non-invasive Vagus Nerve Stimulation (nVNS) is a more accessible and widely used method for headache management. These handheld devices are applied to the skin on the neck, delivering gentle electrical impulses through the skin.
An example of such a device is gammaCore, approved for the acute and preventive treatment of migraine in adults and adolescents aged 12 and older, and for cluster headache in adults. The mechanism of nVNS is thought to involve blocking pain signals and modulating brain circuits associated with headache pain. This approach provides a non-pharmacological option for managing headache attacks.
Natural and Behavioral Vagal Regulation Techniques
Beyond medical devices, several lifestyle and behavioral practices are proposed to enhance “vagal tone,” the activity of the vagus nerve. These techniques aim to support the body’s natural relaxation responses. While generally safe and beneficial for overall well-being, their direct efficacy for treating an acute headache is less established compared to medical devices like nVNS.
One widely recognized technique is deep and slow diaphragmatic breathing, also known as belly breathing. By emphasizing longer exhales than inhales, this practice activates the vagus nerve, which helps to slow the heart rate and regulate the autonomic nervous system. Meditation and mindfulness practices, which encourage present-moment awareness, can also stimulate the vagus nerve through focused breathing and mental relaxation.
Exposure to cold, such as splashing cold water on the face or taking cold showers, can also influence vagal activity. This “diving reflex” can slow heart rate and increase blood flow to the brain. Simple actions like humming, singing, or gargling are thought to stimulate the vagus nerve because it passes near the vocal cords and inner ear, creating vibrations that may activate the nerve.
What to Expect During Stimulation and Potential Side Effects
When using a non-invasive vagus nerve stimulation (nVNS) device, users may feel specific physical sensations. A common experience is a tingling, stinging, or buzzing feeling at the site where the device is applied to the neck. Some individuals may also notice a slight pulling sensation or muscle contraction in the face or neck during stimulation.
The side effects associated with nVNS devices are generally mild and temporary. These can include skin redness or minor irritation at the application site. Users might also experience a temporary change in their voice, such as hoarseness, while the device is actively stimulating the nerve.
Other potential mild side effects include a mild headache or dizziness. These sensations and effects often become less noticeable as the body adjusts to the stimulation over time, or if the stimulation intensity is adjusted. While serious side effects are rare, individuals with certain heart conditions or implanted medical devices should exercise caution and consult with their healthcare provider before using nVNS.