QSART: Diagnosis of Dysfunctions of the Sympathetic Nervous System

This test examines the function of the slow-conducting, non-myelinated nerve fibers (small fibers) that control sweat gland function. Since the test measures the change in skin moisture, it also provides information about the performance of the sweat glands on the examined body part. Under- and over-functioning, i.e. hypohidrosis and hyperhidrosis (as with excessive sweating), can be recorded. Since the sweat gland function can be recorded in up to four body regions simultaneously with the QSART, comparisons between arms and legs or between the right and left side of the body are easily possible. In contrast to the galvanic examination methods, the test response in the quantitative sudomotoric axon reflex test is triggered by the natural messenger substance acetylcholine. This is applied to up to four skin areas. In order to be able to measure the resulting moisture on the corresponding parts of the body, small measuring chambers are positioned before the start of the test.