Somatosensory evoked potenciais after stimulation of the median nerve were obtained in a group of normal individuals. The components obtained between 12 and 22 ms were analysed with cephalic and non-cephalic references. It is shown that the P13-14 complex is the major contributor for the amplitude of the N13 component recorded with electrodes between the posterior neck and the scalp. It has not been possible to detect differences in amplitude or latencies for the components N18 and P22 recorded between FZ-non cephalic and C6-FZ. Implications of these findings to clinical interpretations of the responses are discussed.
evoked potencial; somatosensory; median nerve; subcortical components; cephalic reference; non-cephalic reference