B a c k g r o u n d: Somatosensory evoked potential (SSEP) is valuable for the evaluation of the central pathway.However, peripheral neuropathy sometimes renders the test useless by preventing the conduction from reaching theCNS. We postulated that the peripheral conduction problems could be overcome by proximal stimulation in SSEP andwanted to verify this in the study.Methods: Twenty patients with diabetic sensorimotor polyneuropathy were included. SSEP was elicited by stimulatingthe median and posterior tibial nerves. We compared the effect of distal and proximal stimulations in each SSEP inthe aspect of presence/absence and various latencies of resultant waves.Results: Among the 40 cases, proximal stimulation caused reappearance of subsided waves in 10 cases (25%). In themedian nerve SSEP, proximal stimulation made EN1 and CN2 visible which were not evident when distally stimulated.In the posterior tibial nerve SSEP, there was also improvement of forming waves when proximally stimulated.Conclusions: In the diabetic polyneuropathy, proximal stimulation of SSEP is more effective than the conventionaldistal stimulation in evaluating central pathway.
