Assessing sudomotor impairment in patients with peripheral neuropathy: Comparison between electrochemical skin conductance and skin biopsy

Publication date: July 2018
Source:Clinical Neurophysiology, Volume 129, Issue 7
Author(s): Mathilde Duchesne, Laurence Richard, Jean-Michel Vallat, Laurent Magy
ObjectiveSudoscan provides a rapid assessment of sudomotor function based on the measurement of electrochemical skin conductance (ESC), which is thought to be proportional to small nerve fibres innervating the sweat glands. However, the relationship between ESC and small nerve fibre density on skin biopsy remains unclear.MethodsIn a retrospective single-centre study, we compared ESC measurements with autonomic sweat gland nerve fibre density (SGNFD) and somatic intraepidermal nerve fibre density (IENFD) in patients with polyneuropathy.Results63 patients were included (mean age: 60.6 ± 13.3 years). ESC was more strongly correlated with SGNFD (r = 0.49; p = 0.0005) than with IENFD (r = 0.42; p = 0.0005). Foot ESC was lower in patients with abnormal SGNFD (1.0 ± 0.3 µS/kg versus 0.7 ± 0.4 µS/kg; p = 0.0419) or abnormal IENFD (1.1 ± 0.3 µS/kg versus 0.8 ± 0.3 µS/kg; p = 0.0425).ConclusionESC measurement is a novel method of potential value for assessing sudomotor function. More studies are required to define its place beside ancient well-established techniques.SignificanceThe weak correlation of ESC with skin biopsy results suggests that mechanisms other than the loss of innervating fibres may be responsible for sweat gland dysfunction in polyneuropathies.



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