Augmentation of Late Somatosensory Evoked Potentials (Late SEP) by Train Stimuli

Introduction: Summation of EPSPs promotes suprathreshold excitation of nerve cells, e.g. after train stimuli. SEP have not yet been investigated after train stimuli. Materials and Methods: SEP (C3-Fz) were recorded in 12 volunteers 50ms before and 450ms after the stimulus (12mA, 0.2ms, right N. radialis superficialis). Averages of 60 traces for single stimuli and trains of 3 with interstimulus-intervals (ISI) of 2, 2.5, 3, 4, 5, 6, 7 and 10ms; stimulus repetition: 1Hz, 0.7Hz and 0.4Hz. Statistics: Friedman-ANOVA, Wilcoxon-test. Results: Contrary to the constancy of the P40-component, N1, N2a and N2b showed an in…