A model for in vivo analysis of sudomotor sympathetic C-fiber activation and human sweat gland output.

Quantitative assessment of small-fiber peripheral neuropathy often involves an evaluation of the interaction between the C-fiber sudomotor nerve and local sweat rate (SR). Typically, some sort of quantitative sudomotor axon reflex test (QSART) is performed to aid in diagnosing small-fiber dysfunction. The currently used QSART demonstrates only moderate test-retest reliability and therefore limits its usefulness in tracking small-fiber dysfunction. A new experimental model to examine small C-fiber function in the skin using intradermal electrical stimulation and simultaneous monitoring of SR is proposed. Using intradermal electrical stimulation (1.5 and 2.5 mA) and varying stimulus frequency from 0.2 to 64 Hz, a quantitative relationship between the area under the SR-time curve and log