J Korean Neurol Assoc.  1994 Jun;12(2):262-269.

Clinical Usefulness of Central Conduction Velocity from Posterior Tibial Nerve Somatosensory Evoked Potentials in Thoracic Myelopathy

• Joo IS
• Lee KW

Abstract

Posterior tibial nerve somatosensory evoked potential (PTSEP) is a useful electrophysiologic test for evaluation of the spinal cord lesion. A number of the diseases affecting the spinal cord may cause the change of conduction velocity as well as latency and amplitude of the evoked potentials. The central conduction velocity (CCV) was defined as velocity of the afferent volly between the lower spinal cord and cortex. Authors performed this study to understand the clinical significance of CCV and to know this method using CCV have any superiority to the conventional method using latency and amplitude for detection of spinal cord lesion. Authors have calculated normal data of CCV from the somatosensory evoked potentials after stimulation of the posterior tibial nerve at the ankle in 42 normal subjects and analyzed CCV data from 13 patienes with thoracic myelopathg. The mean CCV in healthy subjects was 40.8 m/s (SD=4.2) and disclosed significant correlation with the factors of age, sex and height (P<0.05, P<0.05 and P<0.001, respectively), but not with side. When we analyzed the PTSEP data of patients with thoracic myelopathy by using CCV, the sensitivity of this method (30.8%) was not significantly different from the sensitivity of the conventional method (69.2%). Therefore, authors concluded the CCV using analytic method did not show any superiority in detecting spinal cord lesion compared with that of the latency using analytic method. However, further study should be performed with more materials to know whether or not the presence of the significant change in sensitivity.

MeSH Terms

Ankle
Evoked Potentials
Evoked Potentials, Somatosensory*
Humans
Spinal Cord
Spinal Cord Diseases*
Tibial Nerve*