Estimate of motor conduction in human spinal cord: slowed conduction in spinal cord injury

By using motor evoked potential (MEP) created by transcranial electric stimulation over the motor cortex and F-wave measurement from the peripheral nerve stimulation, it is possible to estimate the spinal cord motor conduction velocity (SCMCV) in the diseased state. Twenty-four patients with spinal cord injury (SCI) between T1 and T11 neurological levels participated in this study. MEP in leg muscle was absent in all neurologically complete paraplegics. In 16 patients with neurologically incomplete SCI, MEP was obtained in 13 patients. The SCMCV estimated from C7 to T12 spinal levels was 32.1 (SD = 9.4) m/s. This was significantly slower than 63.3 (SD = 8.6) m/s in 40 normal controls. This noninvasive, indirect method is measurable, and can provide valuable electrophysiological data in the assessment of motor function in patients with SCI.