Synonym: Lhermitte’s phenomenon, Barber chair phenomenon
Definition of Lhermitte’s Sign
Lhermitte’s sign (pronounced Ler-meets) is an electric shock-like sensations, spreading along the spine in a cervico-caudal direction and into the arms and legs felt upon active or passive flexion of the neck.
Reverse Lhermitte’s Sign is defined when symptoms are induced by neck extension, not flexion.
Pathophysiology of Lhermitte’s Sign
Because flexion of the neck causes the dysaesthetic symptoms, it has been suggested that an increased mechanical sensitivity of these damaged myelinated axons in the dorsal cloumn of the spinal cord causes an abnormal origin or transmission of sensory information. 1
Neck flexion causes a mechanical stimulation of the damaged myelinated axons by lengthening and deforming the affected area of the cervical spinal cord.
Reverse Lhermitte’s phenomenon is said to be induced by extrinsic compression of the cervical cord and neck collar immobilization.
Causes of Lhermitte’s Sign
- Multiple sclerosis (in 1/3rd patients)
- Vitamin B12 deficiency – Subacute Combined Degeneration of spinal cord (in 1/4th patients)
- Cervical spondylosis
- Cervical spinal cord tumors
- Radiation myelopathy
- Head injuries
- Arnold-Chiari malformation
- High-dose chemotherapy
- Cisplatin neurotoxicity
- Nitric oxide neurotoxicity
- Arachnoiditis 2
Eliciting Lhermitte’s Sign
One patient described it as follows: “When I bent my head, I felt a violent shock in my neck and a pain like an electric current running through my whole body, from the neck down the vertebral column into the feet”. 3
Maneuver: Forward flexion of head (actively or passively)
Outcome: Electric sensation spreading from spine into extremities (symmetrical or asymmetrical)
Lhermitte’s sign were elicited also by:
- Neck rotation, arm abduction, coughing 4
- Yawning 5
Video for Lhermitte’s Sign
Accuracy of Lhermitte’s Sign
Two studies found that the sensitivity of Lhermitt’s sign is markedly poor, ranging from 3 to 17%. One of these studies also found that it presented good specificity (97%) for nonspecific compressive myelopathy. 6