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Quantitative sudomotor axon reflex test (QSART): A new approach for testing distal sites
Author(s) -
Riedel A.,
Braune S.,
Kerum G.,
SchulteMönting J.,
Lücking C.H.
Publication year - 1999
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/(sici)1097-4598(199909)22:9<1257::aid-mus14>3.0.co;2-j
Subject(s) - axon reflex , sudomotor , forearm , medicine , median nerve , thumb , reflex , anatomy , sweat , sensory nerve , sensory system , neuroscience , biology
The quantitative sudomotor axon reflex test (QSART) is a useful tool in the evaluation of C‐fiber function. Because many neuropathies show a length‐dependent loss of nerve function, a new capsule was designed for distal performance of the QSART, allowing measurements on fingers and toes. We investigated 20 healthy volunteers and 15 patients with insulin‐dependent diabetes mellitus and normal sensory nerve conduction studies. A QSART was performed on the forearm and on the thumb. The groups showed no differences in the QSARTs on the forearm, but the sweat volume on the thumb was significantly lower in patients. Calculation of the forearm/finger ratio reduced the interindividual variation and showed the highest sensitivity for detecting C‐fiber dysfunction in the patient group. We conclude that the distal measuring device and the forearm/finger ratio are more sensitive tools for the early detection of distal‐onset neuropathies than are the commonly used proximal testing sites. © 1999 John Wiley & Sons, Inc. Muscle Nerve 22: 1257–1264, 1999.