Effect of conduction distance on amplitude and area of compound action potentials of A fiber and C fiber

Abstract

We used 24 sacral dorsal roots of the rat to analyze amplitude and area changes of biphasic and monophasic compound action potentials (CAPs) at 4 conduction distances. Both the CAPs of the A-fiber and C-fiber were analyzed. The changes were examined with the paired t test and linear regression. All the variables decreased linearly with increasing conduction distance except area of monophasic CAP, which remained constant throughout. CAP data were also compared between the S1 and S2 roots by using the pooled t test. Only area of monophasic CAP showed good correspondence with the anatomical data. Therefore, area of monophasic CAP is suggested as the best parameter for representing the functional state of a nerve.