Sudomotor dysfunction as a measure of small fiber neuropathy in type 1 diabetes

Abstract

Background This study evaluated whether measuring the electrochemical skin conductance (ESC) may be a reliable surrogate for early cardiovascular autonomic neuropathy (CAN). Methods Longitudinal study included 37 type 1 diabetes (T1D) subjects (mean age 38±13 years, duration 15±7 years, HbA1c 7.9±1.1%, no known complications at baseline), and 40 age-matched healthy control (HC) subjects. Mean hands ESC (ESChands) and feet (ESCfeet) were measured with the SUDOSCAN (Impeto Medical, France). CAN was assessed with heart rate variability (HRV) studies (ANSAR Inc., PA), cardiovascular autonomic reflex tests (deep-breathing, Valsalva, postural test), and positron emission tomography with sympathetic analogue [11C]meta-hydroxyephedrine. Associations between measures of CAN and ESC were estimated using Spearman correlations. Longitudinal changes were analyzed using paired t-test. Results At baseline, there were no differences between T1D and HC in ESChands (69±14 vs. 69±13μS; P=0.84) or ESCfeet (82±8 vs. 78±9μS; P=0.12), while some indices of HRV and Valsalva ratio were significantly lower in T1D vs. HC. T1D subjects experienced a significant decline in both ESChands and ESCfeet at 12 months (mean change −7.2±11.6, P=0.0006; −2.8±7.3, P=0.023 respectively). No significant correlations were consistently found between ESC and measures of CAN at baseline or at 12 months. Conclusion Comparing patients with T1D to controls, no differences in ESC were observed at baseline. The associations between ESC and established measures of CAN were inconsistent, which does not support ESC as a reliable surrogate for CAN. While both hands and feet ESC declined over time, the significance of this finding is unclear and warrants further reliability testing.

The diagnostic usefulness of the combined COMPASS 31 questionnaire and electrochemical skin conductance for diabetic cardiovascular autonomic neuropathy and diabetic polyneuropathy

“…Moreover, correlations between ESC and morphology of small fibers have been reported by some authors using skin biopsy parameters although weaker than expected and denied by others using corneal confocal microscopy measures . Finally, ESC has been advocated as a sensitive outcome in an intervention study with bariatric surgery in subjects with prediabetes and type 2 diabetes, but also the associations between ESC and CARTs were inconsistent at 1‐year follow‐up in 37 subjects with type 1 diabetes and free of complications, and the ESC decline unrelated to clinical variables and standard autonomic measures . The position statement of the American Diabetes Association did not recommend routine screening for sudomotor dysfunction in clinical practice …”

“…CARTs were inconsistent at 1-year follow-up in 37 subjects with type 1 diabetes and free of complications, and the ESC decline unrelated to clinical variables and standard autonomic measures. 46 The position statement of the American Diabetes Association did not recommend routine screening for sudomotor dysfunction in clinical practice. 3…”

Cardiac vagal tone as a novel screening tool to recognize asymptomatic cardiovascular autonomic neuropathy: Aspects of utility in type 1 diabetes

“…We used SUDOSCAN® (Impeto Medical, Paris, France) to assess the sudomotor function. This device measures the electrochemical reaction between the chloride ions in the sweat glands and the steel electrodes [15] and provides an ESC readout for all four extremities. Participants placed their hands and feet on the stainless-steel electrodes emitting a low current for 3 minutes.…”

“…[12,13] In addition, assessment of sudomotor function through electrochemical skin conductance (ESC) during a 3-minute test with the SUDOSCAN® has been proposed as a rapid alternative; however, large variability in data generated by different groups, as well a recent metaanalysis, question the SUDOSCAN® ESC sensitivity as a reliable test for CAN. [14][15][16] All the above-mentioned methods are also either unavailable, resource-demanding, or expensive to perform in standard clinical practice. [12,13] Therefore, the implementation of simpler and readily available tests to document the presence of asymptomatic CAN is needed.…”

Electrochemical skin conductance to measure sudomotor function: the importance of not misinterpreting the evidence

“…However, according to published data [14], patients with type-1 diabetes mellitus with peripheral neuropathy had mean ESC of 53.5 ± 25.1 μS while controls and type-1 diabetes mellitus without peripheral neuropathy had mean ESC of 77.1 ± 14.3 μS. In a recently published work [1], patients with type-1 diabetes mellitus whose peripheral neuropathy status was not reported had mean ESC of 82 ± 8 μS. It is also commonly acknowledged that peripheral neuropathy is different in type-1 diabetes mellitus and type-2 diabetes mellitus.…”