[Routine study of somatosensory evoked potentials in healthy persons. II. Tibial nerve].

60 healthy volunteers ranging in age from 15 to 75 years participated in the study. Tibial nerve was stimulated unilaterally or bilaterally at the ankle and SEPs were recorded along the somatosensory pathway. Determination and readability of the potentials were evaluated according to the stimulating and recording method. After unilateral stimulation, the following derivation system was regarded as most useful in routine testing: L4 - Ic (iliac crest), Th12 - Ic, Cz' - Fz, Fz - Shoulder (and, if possible C7 - Fz). When more detailed spinal cord diagnosis is indicated, bilateral stimulation and recording in montage: Th6 - Shoulder, C7 - Shoulder, C7 - Fz, Fz - Shoulder may be helpful. In the study normal values of parameters of the potentials from certain derivations were presented: latencies, amplitudes, peripheral conduction velocities and central conduction times were taken into account. According to our own results (correlative analysis of SEP parameters) and the results of other authors, interpretation of the potentials on various levels of the ascending somatosensory pathway was discussed.