Effects of acute nerve compression on conduction of impulse trains of increasing frequency.

The acute effect of localized nerve compression has been detected electrophysiologically in isolated rat tail nerve by utilizing a special stimulus pattern, a STIF (Stimulus Train of Increasing Frequency), which shows the highest frequency that the most sensitive axons in a compound potential can transmit through the compressed region. The same method also detected recovery after release of compression. Overlap of waveforms at high frequencies of stimulation required special techniques to permit unequivocal measurements. The best endpoint at which to detect the acute nerve compression in these experiments was found to be that frequency at which only a few fibers were blocked. The method was also effective when part of the nerve was completely blocked by the compression, and was more sensitive than measure of change in latency of a single response.