With the advent of a magnetic stimulator, we can more easily obtain motor evled potential and more comprehensive information of the function of a peripheral and central somatic sensori-motor pathway to the bulcocavernosus muscles.
So in this study, bulbocavernosus reflex study and pudendal somatosensory evoked potential combined with motor evoked potential from the bulbocavernosus muscle by using magnetic stimulator, were carried out in neurologically normal adult male with the purpose of providing a future guide for a integrated information for localizing the levels of impaired neural conduction. Following results were obtained from twenty four neurologically normal male studied. Motor evoked potential studies were recorded from the bulbocavernosus muscle after transcranial magnetic stimulation and sacral magnetic stimulation. 1) The mean total motor conduction time, peripheral and central motor conduction time were 21.8⁑2.5 msec, 6.4⁑1.2 msec and 15.4⁑2.9 msec respectively and there were no significant differences in both sides. 2) The mean bulbocavernosus reflex latency and calculated efferent peripheral conduction time (EPCT) were 32.2⁑3.2 msec and 11.2⁑1.2 msec individually, and all those showed no significant differences between right and left sides. And the mean cortical P40 potentials were 38.2⁑2.1 msec. 3) The peripheral motor conduction time by sacral stimulation was shorter than the calculated efferent peripheral conduction time. These results suggested that the excitated site of spinal nerves by magnetic stimulation was not the spinal cord but peripheral nerves or roots.
