Lhermitte’s sign is a short, intense, electric-shock like sensation that passes down the neck and spine and radiates through the trunk and limbs. It is a symptom of multiple sclerosis (MS) but can affect people without MS.

Some people refer to Lhermitte’s sign as the barber chair phenomenon because it can happen when a person bends their head forward rapidly.

The sensation may feel akin to an electric shock. It results from the stimulation of irritated nerves or the spinal cord and causes a sensation similar to hitting the elbow or “funny bone.”

In this article, we look at why Lhermitte’s sign happens and how it relates to multiple sclerosis (MS). We also discuss the treatment options and explain when someone should see a doctor about this symptom.

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Lhermitte’s sign most often occurs with MS. MS happens when the body mistakenly attacks the central nervous system (CNS). The CNS comprises the brain and spinal cord.

MS damages the myelin sheath, the protective, insulating material that coats the nerve fibers in the brain and spinal cord.

This damage interrupts the flow of signals across parts of the CNS, resulting in a range of sensory and motor symptoms.

There are two main causes of Lhermitte’s sign. The first is demyelination, which damages the myelin around the nerves. The second is hyperexcitability, the increased firing of nerve fibers in the brain.

Miscommunication between damaged nerve fibers can also cause Lhermitte’s sign.

Lhermitte’s sign is present in other demyelinating disorders, such as neuromyelitis optica, which affects the optic nerve and spinal cord.

It can also occur with other medical conditions and treatments that affect the spinal cord in the neck region.

These include:

  • spinal cord compression due, for example, to a tumor
  • spinal cord injury
  • radiculopathy
  • cervical spondylitis
  • transverse myelitis
  • spinal cord degeneration
  • some radiation or chemotherapy treatments for cancer
  • stopping the use of some antidepressant drugs may increase the risk
  • inflammation due to injury or damage to the spinal cord (myelopathy)
  • Arnold-Chiari malformation
  • Behçet’s disease, a rare autoimmune disorder causing inflammation in the blood vessels
  • shingles
  • systemic lupus erythematous
  • receiving anesthesia or another intervention to the spine
  • nitric oxide toxicity
  • cervical disk disorders, which affect the top of the spine

Several case studies suggest a link between vitamin B12 deficiency and Lhermitte’s sign. Vitamin B12 is necessary for the production and maintenance of myelin, the fatty substance that makes up the myelin sheath and covers nerve fibers.

The findings of a 2015 study suggest that Lhermitte’s sign affects 1 in 3 people with MS. About 16% of the participants reported experiencing it during their first episode of MS.

Triggers

Lhermitte’s sign can occur when a person flexes their neck — for example, if they bend their neck forward suddenly so that the chin touches the chest.

Other triggers include:

Lhermitte’s sign is different from Uhthoff phenomenon. With the Uhthoff phenomenon, MS’s neurological symptoms worsen temporarily on exposure to heat. They may get worse, for example, when using a sauna.

Education and reassurance are often enough to help most people manage the discomfort of Lhermitte’s sign. It often goes away after several months to a year.

However, a doctor may recommend treatment if it happens often and significantly affects a person’s quality of life.

Various treatment options may help manage the pain of Lhermitte’s sign and other MS symptoms.

Managing stress

Relaxation techniques can help some people. They include:

A doctor can advise on a suitable stretching routine.

Mechanical devices

Wearing a soft neck brace may help a person avoid neck movements that trigger Lhermitte’s sign.

Electrical stimulating devices, such as transcutaneous electrical nerve stimulation units, use a mild electric current to ease the pain. These electrical pulses help reduce pain signals and relax the muscles.

They may also lead to the production of hormones called endorphins that act as natural pain relievers.

Drugs

There is no specific drug treatment for Lhermitte’s sign. However, there is some anecdotal evidence that the following anticonvulsant seizure medications may help:

  • carbamazepine (Tegretol)
  • oxcarbazepine (Trileptal)
  • gabapentin (Neurontin)

Generic medications that may help to reduce symptoms include muscle relaxers and antidepressants.

People who experience Lhermitte’s sign for the first time might fear that their MS is worsening. However, this is not necessarily the case.

However, it may be a good idea to speak with a doctor, as they may be able to suggest treatment options.

Treatment can help people manage the pain that occurs with Lhermitte’s sign and other MS symptoms.

If Lhermitte’s sign occurs in a person without a diagnosis of MS or another known demyelinating condition, they should consider speaking with a doctor. Lhermitte’s sign can sometimes be an early sign of MS.

Lhermitte’s sign is an electric shock-like sensation that affects the neck and spine. It is usually sporadic and does not last long. However, it may recur. It often resolves without treatment after several months or up to a year.

It can affect people with MS when they suddenly move their neck or head. However, it does not only occur with MS.

Lhermitte’s sign can be bothersome and uncomfortable. However, it is not life threatening and does not mean MS is getting worse.

Anyone with MS who unexpectedly experiences such a sensation may wish to let their doctor know. The doctor may be able to suggest ways of reducing its impact.