H-reflex of the upper extremities in cervical myelopathy.

A study was made of the H-reflex in the upper extremities to express objectively the degree of spastic paralysis in cases of cervical myelopathy. This reflex cannot normally be elicited in healthy persons. The H-reflex was elicited in 63 out of 80 patients with advanced symptoms of cervical myelopathy and was most frequently recorded from the median nerve. The H/M amplitude ratio is used to express the degree of spastic paralysis, the higher the ratio the more severe the dysfunction. The longer the clinical history the greater the tendency for the H-type of reflex to change to the HF-type and the higher the H/M amplitude ratio. The decrease rate of the pre- and post-operative H-reflex was high amongst soft disc cases whilst that in spondylosis and ossification of the posterior longitudinal ligament was low compared to the improvement in symptoms. It is concluded that the H-reflex in the upper extremities is a good method of expressing the degree of spastic paralysis in cervical myelopathy.