Hideshi Tsuboya, MD, Toshikazu Tani, MD, Kenji Ishida, MD, Takahiro Ushida, MD, Shinichirou Taniguchi, MD, Jun Kimura, MD
This study conducted a sequential study of quantitative sensory testing (QST) during compression-induced conduction block of the median nerve to determine relative vulnerability of the small and large myelinated nerve fibers. Cold (CPT) and vibratory perception thresholds (VPT) of the third digit in 15 healthy subjects during constant, localized compression for 30 min of the median nerve at the wrist was tested. After the onset of nerve compression, it took 16 min for CPT to show the first change; VPT remained normal for 26 min. CPT recovered 2 min later than VPT after release of compression. The authors conclude that contrary to the common belief, a focal compression sufficient to produce rapidly reversible conduction abnormalities affects the slow-conducting small myelinated fibers mediating cold perception before the fast-conducting large myelinated fibers transmitting vibration perception. These findings suggest that testing CPT, rather than VPT, provides a better QST to delineate rapidly reversible symptoms induced by compression.
Muscle & Nerve, Volume 35, Issue 4 , Pages 458 – 464