A Study of the Conduction Velocity of Sensory Fibers 'of the Ulnar Nerve in leprosy!

Measurement of peripheral nerve conduction in man dates back to von HelmhQltz ( 1:' . Ili) and now forms a part of routine clinical examination in various neuropathic conditions. Prominent in this group is leprosy, but it is surprising to note in an editorial by Wade ( 18) that as late as 1954 sufficient information on the conduction velocity of peripheral nerves in leprosy was not available. In 1966 Granger ( 10 ) reported that he was unaware of any nerve conduction studies in leprosy. Beca use of the absence of information of such nature, which can often, without the help of a biopsy, indicate the state of peripheral nerves in various stages and forms of leprosy, a proper correlation between the large amount of histopathologic and clinical data available has not yet been fruitful. Jopling and Morgan-Hughes (12) measured the conduction velocity of the motor fibers of the ulnar nerve in a case of pure neural tuberculoid leprosy. The conduction velocity of the fastes t fibers in the wristelbow segment was found to be about 41 m/ sec. (meters per second). A few fibers conducted at velocities between 11 and 25 m/ sec. However, in the presence of impaired sensation over the ulnar area, they could not record sensory potentials above the wrist on stimulation of the digital nerves. In a case of tuberculoid leprosy Granger ( 10 ) could not record sensory action potential from the affected ulnar nerve, while the velocity of the motor fibers was about 32 m/ sec. The following experiments describe a study of the sensory conduction velocity of the ulnar nerves in 23 cases of leprosy.