DECREASE IN NERVE TEMPERATURE - A MODEL FOR INCREASED TEMPORAL DISPERSION

A decrease in nerve temperature causes a proportional decrease in cond uction velocity which, in percentage terms, is equal for all nerve fib ers. The absolute decrease in conduction velocity is larger for faster conducting nerve fibers. This results in a compression and a shift to lower values of the conduction velocity distribution and an increase in temporal dispersion. The purpose of this study was to determine if these effects could be detected by a combination of two collision tech niques designed to obtain the motor conduction velocity distribution a nd refractory period distribution. In 12 healthy volunteers we measure d the conduction velocity distribution in the median nerve at nerve te mperatures of 25 and 40 degrees C. The results showed that our method could detect the predicted changes in conduction velocity distribution and temporal dispersion. We conclude that temperature change is a mod el that can be used to study temporal dispersion. This may be a first step towards distinguishing between the effects of conduction block an d (abnormal) temporal dispersion in demyelinated nerve fibers. (C) 199 8 Elsevier Science Ireland Ltd.