Somatosensory evoked potentials following stimulation of the tibial, peroneal and sural nerves using four different montages.

Cortical and lumbar somatosensory evoked potentials (SEPs) were recorded following unilateral stimulation of the tibial, peroneal and sural nerves in 20 normal adults. The active cortical electrode (Cz) was referred to either a cephalic (mid-forehead, contralateral central scalp, linked ears) or a non-cephalic (contralateral shoulder) site. The configuration of the short-latency cortical SEP waveforms was nearly identical irrespective of the nerve stimulated or the location of the reference. Central conduction times (CCTs) were also calculated by subtracting the peak latency of the lumbar SEP from that of the primary cortical response following stimulation of the tibial and peroneal nerves. A stronger relationship was consistently observed between the absolute cortical latency and height than between CCT and height. The potential clinical applications of the results are discussed.