Overview of Lhermitte's Sign

If you have been told that the electrical shock-like sensation that runs down your back, arms, or legs is Lhermitte's sign, you may be concerned about what this means for you. Lhermitte's sign is usually triggered by lowering your chin towards your chest, which is why it has also been called the barber chair phenomenon.

This can occur with a number of neurological conditions, and while it is most closely associated with multiple sclerosis (MS), you may experience Lhermitte's sign if you have any problem that affects your cervical (upper) spine.

Despite being called "Lhermitte's sign," the first people who described this phenomenon were Pierre Marie and Chatelin in 1917. Jean Lhermitte was a French neurologist who published an article on the subject in 1924, which led to wider knowledge about the symptom.

Lhermitte's sign is a sense of electricity that shoots down the spine, often out through the arms and legs as well. It is described as uncomfortable or unusual but is rarely painful.

You may spontaneously experience it, or you may feel it during your physical examination. If you are being evaluated for a neurological disease, your doctor may ask you to flex your neck forward as part of your examination to identify Lhermitte's sign.

The symptoms will last for a few seconds at a time, and they can be worrisome if you don't know why you are having these sensations.

Lhermitte's sign is caused by dysfunction of the dorsal (posterior, or back) columns of the cervical spinal cord, which are responsible for transmitting information about light touch, vibration, and proprioception (the sense of where your body is in space) to the brain.

Lhermitte's sign is classically associated with multiple sclerosis (MS), a condition characterized by episodes of weakness, sensory changes, and/or visual deficits. In addition to MS, Lhermitte's sign can be the result of many other problems that affect the cervical spinal cord.

Conditions that can cause Lhermitte's sign include:

• Myelinopathy (spine disease) from B12 deficiency
• Cervical spine inflammation, which can be caused by conditions such as lupus, an infection, or Bechet's disease
• Transverse myelitis (a sudden episode of spine dysfunction)
• Cervical spinal cord tumors
• Spondylosis (arthritis in the neck)
• Chemotherapy
• Radiation to the spine
• Trauma
• Arnold-Chiari malformation, which is when the brainstem is located in a lower position than it should be
• Nitrous oxide toxicity—with nitrous oxide toxicity there is often a "reverse Lhermitte's sign, in which the electrical sensation travels in the opposite direction, from the feet toward the head

If you have Lhermitte's sign, your doctor will do a thorough evaluation to find the cause. The most important aspect of your medical evaluation is your medical history. Any other complaints you have will direct your doctor to the cause of your problem. For example, if you have double vision, this suggests that multiple sclerosis could be the cause. If you have joint pain, arthritis could be the cause.

Your physical examination is another very important aspect of your evaluation. Your doctor can detect changes such as weakness, decreased sensation, reflex changes, and swelling in your neck to localize the area where the problem is coming from.

Often, diagnostic tests such as cervical spine MRI or lumbar puncture (LP, often also called a spinal tap) can help identify the disease that is causing you to experience Lhermitte's sign.

It is important for you to know that, while Lhermitte's sign is uncomfortable, it isn't dangerous in and of itself. Treatment is focused on two things—one is managing the cause of Lhermite's sign, and the other is maintaining your comfort if the experience is interfering with your life.

Certain lifestyle and noninvasive approaches can help prevent symptoms, including:

• Breathing exercises such as deep breathing exercises
• Stretching
• Posture adjustment and alignment: It's important to have a therapist assist you in learning these measures— as some exercise may actually worsen the symptoms

Medical interventions may be necessary if simple lifestyle modifications are not enough to manage your symptoms.

• Acupuncture or massage
• Neck braces or collars can prevent your head movements from triggering your symptoms
• Spinal cord stimulation: Electrical stimulating devices that send low-voltage electricity to the nerves, either from outside the body or through an implantable device (TENS units), may help

Certain medications can help reduce discomfort if you have prolonged symptoms, and can also reduce pain related to your neurological condition.

• Antiseizure medications (anticonvulsants): Prescriptions such as Neurontin (gabapentin) and Lyrica (pregabalin) may help with pain
• Antidepressants: Tricyclic antidepressants are often used to help manage chronic pain.
• Steroids: Oral steroids have significant side effects when used long-term, but may be used for an acute flare up when inflammation is the cause.

If you have recurrent Lhermitte's sign, the most important thing to keep in mind is that it is safe for you to move your neck and arms when the symptoms occur. However, since neck movements can trigger the electrical shock-like sensations, you may inadvertently begin to stiffen your arms or neck. Be sure to maintain regular exercise so that you don't develop tightness of your neck and shoulder muscles as you are coping with your condition.