Test–Retest Reliability of Quantitative Sudomotor Axon Reflex Testing

Abstract

To determine the reliability of quantitative sudomotor axon reflex testing (QSART). The QSART at four sites was performed at two time points (n = 20 healthy participants) to determine the intraclass correlation coefficient with 95% confidence intervals. The standard error of measurement and minimal detectable change for men and women was obtained from QSART values from a larger cohort (n = 67). Intraclass correlation coefficients (95% confidence intervals) for the forearm, proximal leg, distal leg and foot were 0.75 (0.46 to 0.89), 0.49 (0.07 to 0.77), 0.71 (0.38 to 0.88) and 0.48 (0.07 to 0.76). Standard error of measurements ranged from 0.666 to 0.978 µL for men and 0.273 to 0.653 µL for women. Minimal detectable changes ranged from ±1.847 to ±2.712 µL for men and ±0.756 to ±1.809 µL for women. We observed moderate test-retest reliability for QSART with a large standard error of measurements and minimal detectable changes for both men and women. The results of this study suggest limited utility of QSART for monitoring sudomotor function in longitudinal and interventional studies.