[Spinal and cerebral somatosensory evoked potentials in single and double stimulation of the tibial nerve]

In 33 normal subjects aged between 15 and 60 years, the cortical somatosensory evoked potentials (SEP) recorded above the mastoid process, HWK2, LWK1, and the nerve action potential above the poplitea were examined following single stimulation of the tibial nerve at the medial malleolus. There is a correlation between size and N1, P1 latencies of the cortical SEP, but no relationship was found between age and N1, P1 latencies. The spinal conduction velocity determined as the difference between HWK2 and LWK1 did not show any correlation with age. The double stimuli examination showed a rise in the N1, P1 latencies within the relative refractory period on shortening of the interstimulus time. The cerebral relative and absolute refractory times were higher than those of the median nerve.