Lhermitte's Sign is common among MSers. Lesions of many kinds in the Cervical (neck) Spinal Cord can produce it; but, it is usually found mainly in MS.

The sensation is generally described as electrical, or tingling. It may shoot down the back of both legs, out one arm, down one side of the body. The distribution depends on the exact site of the lesion.

Many describe this as a feeling of being plugged into an electrical outlet.

It usually occurs when the neck is bent forward, but lasts only a moment. It then disappears whether or not the neck is straightened. Occasionally it remains as long as the neck is bent.

Although it almost always comes from a plaque in the Cervical Spinal Cord, it can affect the lower extremities as well. Like most MS symptoms it comes and goes on its own without treatment, and has no special significance for prognosis.

• Kanchandani, R; Howe, JG. 1982. Lhermitte's sign in multiple sclerosis: A clinical survey and review of the literature. J Neurol Neurosurg Psychiatry 45:308-312.

Lhermitte's sign occurred in 33% of MS patients and was the presenting symptom in 16%. Review of the literature suggests that it occurs rarely in other conditions.