Analysis of the Sweat Response According to the Pathology in Neurologic Patients (Sudoscan)

Sweat glands are innervated by thin and un myelinated sympathetic C-fibers that can be impaired in neuropathies,especially length-dependent ones. Sweating dysfunction has been shown in several neurological peripheral disorders and it has been suggested that sweating function should be included among the diagnostic tests for the early detection of autonomic neuropathies. Several methods have been developed, but the lack of easy and quick tests to diagnose sweating dysfunction has restricted widespread use in clinical practice. Measurement of electrochemical skin conductance (ESC) using Sudoscan® is a new method for quick, non-invasive and quantitative assessment of sweating. This technique has demonstrated its usefulness in detecting autonomic and small fiber neuropathy, especially in diabetic patients.The aim of this study was to evaluate the performance of the laboratory battery of CV tests and of sweating dysfunction by Sudoscan®, alone or in combination, to differentiate MSA-P from PD. Among the CV tests, the present study particularly looked at those tests already recommended as screening bedside tests in diabetic patients (HR variations with deep breathing and BP variations during stand test) ; these tests are rapid and easy to perform. HR variations with deep breathing depend on parasympathetic tone and BP variations depend on vasomotor sympathetic response.