Increased V/D-ratio in lumbosacral SEP's as a new electrophysiological measure of spasticity.

Abstract

Open-label, prospective study. To establish the amplitude-ratio of V-response and D-response (V/D-ratio) as a new measure of spasticity, comparing the motor effect of the H-reflex to the sensoric input. In 13 legs of seven patients with spasticity and in four legs of patients without central nervous system disease, maximal M-response and maximal H-reflex were recorded. Lumbosacral SEP's were recorded with the same stimulus parameters as the maximal H-reflex. H/M-ratio and V/D-ratio were compared to the increased muscle tone. The H/M-ratio and the V/D-ratio in legs with spasticity differed significantly from the H/M-ratio and the V/D-ratio in normal legs. But only the V/D-ratio was higher in legs with moderately or highly increased muscle tone than in legs with slightly increased muscle tone. The V/D-ratio increases in spasticity and shows an even closer relationship to increased muscle tone than the H/M-ratio.