Abnormal nervous system physiology Lhermitte's sign 2019-05-23T22:58:55Z Lhermitte's phenomenon An electric shock-like sensation that occurs on flexion of the neck. This sensation radiates down the spine, often into the legs, arms, and sometimes to the trunk. Barber chair phenomenon Lhermitte's sign is caused by miscommunication between the nerves that have become demyelinated. The pathophysiology of Lhermitte's sign was described as the stretching of the hyper excitable demyelinated dorsal column of the spinal cord, particularly at the cervical level, thus triggering an electric shock-like sensation.