[Somatosensory evoked cortical potentials (SSEP) in regenerating nerves following suture (author's transl)]

In 37 patients with sutured median and ulnar nerves 106 SSEP were evaluated. Stimulation of the finger nerves was performed at a rate of 4-6/sec. In the early stage of reinnervation, just when the electrical stimulus was perceived, the second positive component (P2) of the SSEP could be recorded, but the primary part of the SEP (N1/P1) was highly reduced or absent. At this time no peripheral nerve action potential or muscle action potential could be obtained. In a follow-up study the sensory regenerating process expressed in a clinical sensibility index (S1-S4+), corresponded well with latency and amplitude of the primary potential of the SSEP: N1-latency decrease and N1/P1 and especially P2/N3-amplitude increase corresponded with improving sensibility. The abnormally high P2-wave is assumed to be an expression of central adaptation and reintegration. The method seems to be of diagnostic value as a test of peripheral nerve function especially in early and late stages of reinnervation, in verification of collateral reinnervation and in objectifying sensory defects in forensic cases.