[Clinical and experimental studies on ascending cauda equina action potential (A-CEAP) in lumbar lesion with reference to positivisation].

The phenomenon of positivisation in ascending cauda equina action potential (A-CEAP) was evaluated in 114 patients with lumbosacral lesions. These patients were divided into two groups, i.e., non-positivisation and positivisation group. In the former, positive wave ratio was highest at the L5/S upon stimulating the peroneal nerve. In the latter, the positivisation at the L4/5 upon stimulating the peroneal nerve spread not only to the cranial level but also to the caudal-L5/S level. Based on these experimental results, the factors causing positivisation in the L5/S level without lesion were: 1) curving effect of the L5 nerve root, 2) augmentation of current density within the spinal canal and 3) the amount of individual impulses propagating along the L5 and S1 root.