Hand Electrochemical Skin Conductance Research Articles

Sudomotor dysfunction is associated with impaired left ventricular diastolic function in persons with type 2 diabetes: a cross-sectional study.

The incidence of preserved ejection fraction heart failure has significantly increased in persons with type 2 diabetes mellitus (T2DM). Left ventricular (LV) diastolic dysfunction is an early and important manifestation of preserved ejection fraction heart failure. The onset of heart failure in persons with diabetes is associated with diabetic neuropathy. However, the relationship among sudomotor function, which is an early manifestation of small fiber neuropathy, and LV diastolic function remains unclear. This study aimed to explore the association between sudomotor function and LV diastolic function in persons with T2DM. In total, 699 persons with T2DM were enrolled and divided into three groups according to electrochemical skin conductance (ESC) assessed using the SUDOSCAN device: "no dysfunction" group (NSF), "moderate dysfunction" group (MDF), and "severe dysfunction" group (SDF). LV diastolic function was assessed using Doppler echocardiography. To evaluate the relationship between ESC and echocardiographic parameters, Pearson's correlation analysis was performed. Additionally, logistic regression analysis was used to determine the association between LV diastolic function and ESC. A receiver operating characteristic (ROC) curve was constructed to evaluate the performance of sudomotor function indicators in detecting impaired cardiac diastolic function. There were 301 persons (43.06%) in the NSF group, 232 (33.19%) in the MDF group, and 166 (23.75%) in the SDF group. Compared to the NSF group, the MDF and SDF groups had higher A and E/e' and lower e' values (all p < 0.05). Pearson's correlation analysis showed that A and E/e' were negatively associated with foot ESC (FESC) and hand ESC (HESC), whereas e' was positively associated with FESC and HESC (all p < 0.05). After adjusting for confounding factors, binary logistic regression analysis showed that ESC was independently associated with impaired LV diastolic function (p = 0.003). The area under the ROC curve values for FESC and HESC were 0.621 and 0.635, respectively (both p < 0.05). Deteriorating sudomotor function was associated with reduced diastolic function indicators. ESC can be used as a biomarker for detecting LV diastolic impairment.

Normal values of sudomotor function assessed by electrochemical skin conductance in African population

BackgroundDysfunction of small nerve fibers remains a major public health concern. Subjects suspected of having small nerve fiber damage need to undergo reliable tests to confirm the diagnosis. Sudomotor function test is a reliable noninvasive exploration for detecting peripheral neuropathies. Nevertheless, the normal reference values derived from the sudomotor function test are not known in the African population. The objective of this study was therefore to describe the normal values of Electrochemical Skin Conductance (ESC) measured by the sudomotor function test in healthy African subjects. Materials and methodsBetween December 1st, 2021 and May 31st, 2022, ESC was measured in 475 healthy subjects (median age: 42 [31–53] years, 46% men) using a sudomotor function test, in the hands and feet. Investigators proposed the examination and received participants’ consent; demographic, anthropometric, biological, and clinical data were obtained before the test. Data on 475 healthy study participants who underwent sudomotor function testing was collected and analyzed. The sociodemographic (age, sex), anthropometric (weight, height, waist circumference, body mass index), diastolic blood pressure, systolic blood pressure, heart rate, and electrochemical skin conductances of the hands and feet were assessed. ResultsESC values were statistically higher in men compared to women (right hand ESC: 70 [60–78] versus 63 [53–72], left hand ESC: 72 [61–80] versus 68 [57–75], right foot ESC: 77 [82–99] versus 72 [64–79], ESC left foot: 76 [68–82] versus 72 [62–78] respectively). ESC values were significantly inversely correlated with age (right hand ESC: r=−0.12, P=0.006; left hand ESC: r=−0.11, P=0.01; right foot ESC: r=−0.37, P<0.0001; ESC left foot: r=−0.38, P<0.0001). ESC values measured in feet were significantly inversely correlated with body mass index (right foot r=−0.22, P<0.0001; left foot r=−0.21, P<0.0001). ConclusionThis study reports normal reference values for ESCs according to age and gender in the healthy African population. Progressive decrease in ESC with aging is confirmed by our data. The value of ESC seems lower in the African population than in other reported ethnicities. This finding needs to be further explored in additional studies.

Alterations in electrochemical skin conductance as a marker of autonomic dysfunction in multiple system atrophy

BackgroundMultiple System Atrophy (MSA) is a rare neurodegenerative disease with pronounced autonomic failure (AF). Severe cardiovascular AF is associated with poor prognosis. Since sweating dysfunction is less well known, we investigated the interest of a quick and non-invasive assessment of sweating using electrochemical skin conductance (ESC) as a marker for AF in MSA. Methods138 MSA patients of the French Reference center for MSA with an annual follow-up including the Unified MSA Rating Scale (UMSARS), COMPASS (autonomic symptoms) and measurements of foot and hand ESC (Sudoscan®) participated to this study (age 65 ± 8 years, 66% probable MSA, 72% AMS-P). Statistical analysis included: (i) correlations between ESC and MSA type, age, disease duration, severity, blood pressure (BP), COMPASS, (ii) comparisons between groups with normal or abnormal ESC, and (iii) multivariate analysis by logistic regression. Relationships between severity progression during follow-up with ESC and other variables were modeled by Generalized Estimating Equation. ResultsHands and feet ESCs were abnormal in 81/138 (59%) and 93/138 (67%) cases, respectively. Abnormal ESCs were significantly correlated to disease severity and several features of AF. ESCs worsening over time was more pronounced than other autonomic features such as orthostatic hypotension. Abnormal ESCs at baseline were significantly associated with a higher progression of UMSARS's score during follow-up. ConclusionSweating dysfunction assessed by ESC is frequent in MSA and is significantly related to disease severity and AF. The gradual decrease in ESC with disease duration could be useful as a quantitative marker of autonomic dysfunction.

420-P: Effects of Liraglutide on Sudomotor Function in Subjects with Type 2 Diabetes

Background: Sudomotor (SM) dysfunction is present in small-fiber neuropathy and correlates with the presence of cardiac autonomic neuropathy (CAN). In type 2 diabetes (T2DM), CAN is associated with increased risk of cardiovascular (CV) events and treatment with GLP-1 receptor agonists (GLP1RA) has been shown to improve CV outcomes. However, the effects of GLP1RA on autonomic function need further investigation. The aim of this study was to examine the effects of Liraglutide (Lira) on SM function in patients with T2DM. Methods: Randomized, double-blind, placebo (pb) control study of Lira 1.8 mg vs. pb daily for 52 weeks. Primary outcome was mean change in feet and hands electrochemical skin conductance (ESC). Subjects underwent SM function testing (SudoscanTM, Impeto Medical-Paris) and cardiac autonomic function (CAF) testing (ANX 3.0; ANSAR Group, Inc. Philadelphia). Results: We randomized 44 subjects (21 to Lira and 23 to pb). Baseline characteristics were similar between the groups. Main results after 52 weeks of intervention are shown in Table 1. Mean change on feet ESC was not significantly different between the groups (mean=3.37[95%CI=-2.98-9.60] for Liraglutide vs. -1.56 [-5.07-1.95] for placebo, p=0.136). The same was observed for mean hands ESC and CAF. Conclusions: This study did not show changes in SM or CAF function after 52 weeks of treatment with Lira. The small sample size may have contributed to the negative result. Disclosure C. M. Casellini: None. M. D. Bailey: None. H. Parson: None. E. S. Siraj: Consultant; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Novo Nordisk. Funding Novo Nordisk

MO736ELECTROCHEMICAL SKIN CONDUCTANCE BY SUDOSCAN: A NEW TOOL TO PREDICT INTRA-DIALYTIC HYPOTENSION

Abstract Background and Aims Intradialytic hypotension (IDH) is a common complication in hemodialysis (HD) patients. It is associated with multiple risk factors including cardiac dysfunction and alterations of the peripheral autonomic nervous system. To which extent, dysautonomia may contributed to the occurrence of IHD remains elusive. We sought to investigate the clinical utility of Sudocan®, a device that quantify dysautonomia, in the prediction of IDH. Method We conducted a prospective monocentric study in adult HD patients from July 2019 to February 2020. Dysautonomia was assessed by the measurements of hand and foot Electrochemical Skin Conductance (ESC) by Sudocan®, before and after the end of HD. A pathological hand ESC was defined by an ESC value &amp;lt; 40 μs in Caucasian or &amp;lt; 30 μs in afro-American and Caribbean patients, and a pathological foot ESC by a value &amp;lt; 50 μs in Caucasian or &amp;lt; 30 μs in afro-American and Caribbean patients. Arterial blood pressure (BP) was monitored before, every thirty minutes and after the end of the HD session. The primary end point was the incidence of IDH, according to the NKD/K-DOQI definition, during the 3 month-period study. Results A total of 176 HD patients (64 ±14 years old) were enrolled. Mean pre-dialysis hand and foot ESC were 45±20 μS and 54±22 μS, respectively. Thirty-five and 40% of patients had a pathological ESC at the hand and foot, respectively. Forty-Six IDH occurred during the study period. Logistic regression showed that a pathological hand ESC was associated with an increased risk of IDH [OR=0.39, IC95% (0.15-0.97), p= 0.04]. The cumulative risk incidence of IHD during the study was 2.17 [IC95% (1.21-3.89), p= 0.01] and 1.89 [IC95% (1.06-2.38), p= 0.03], with a pathological hand and foot ESC, respectively. Conclusion A pathological hand ESC, as assessed by a simple, non-invasive test, such as Sudoscan®, is associated with an increased risk of IDH.

Electrochemical skin conductance by Sudoscan®: a new tool to predict intradialytic hypotension

BackgroundIntradialytic hypotension (IDH), a common complication in haemodialysis (HD) patients, is associated with multiple risk factors including cardiac dysfunction and alterations of the peripheral autonomic nervous system. To what extent dysautonomia may contribute to the occurrence of IDH remains elusive. We sought to investigate the clinical utility of Sudocan®, a device that quantifies dysautonomia, in the prediction of IDH.MethodsWe conducted a prospective monocentric study in adult HD patients from July 2019 to February 2020. Dysautonomia was assessed by the measurements of hand and foot electrochemical skin conductance (ESC) using Sudocan®, before HD. The primary endpoint was the incidence of IDH (The National Kidney Foundation/Kidney-Dialysis Outcome Quality Initiative definition), according to the presence of a pathological hand and/or foot ESC value, during the 3-month study period.ResultsA total of 176 HD patients (64 ± 14 years old) were enrolled. Mean pre-dialysis HD hand and foot ESC was 45 ± 20 and 54 ± 22 µS, respectively. About 35% and 40% of patients had a pathological ESC at the hand and foot, respectively. IDH occurred in 46 patients. Logistic regression showed that pathologic pre-dialysis HD hand ESC was associated with an increased risk of IDH [odds ratio = 2.56, 95% CI (1.04–6.67), P = 0.04]. The cumulative risk incidence of IHD during the study was 5.65 [95% CI (2.04–15.71), P = 0.001] and 3.71 [95% CI (1.41–9.76), P = 0.008], with a pathological hand and foot ESC, respectively.ConclusionsA pathological hand ESC, as assessed by a non-invasive Sudoscan® test, is associated with an increased risk of IDH.

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

The study investigated the diagnostic performance for diabetic cardiovascular autonomic neuropathy (CAN) and diabetic polyneuropathy (DPN) of the combined use of composite autonomic symptom score (COMPASS) 31, validated questionnaire for autonomic symptoms of CAN, and electrochemical skin conductance (ESC), proposed for detecting DPN and CAN. One-hundred and two participants with diabetes (age 57 ± 14 years, duration 17 ± 13 years) completed the COMPASS 31 before assessing cardiovascular reflex tests (CARTs), neuropathic symptoms, signs, vibratory perception threshold (VPT), thermal thresholds (TT), and ESC using Sudoscan. Two patterns were evaluated: (a) the combined abnormalities in both tests (COMPASS 31+ESC), and (b) the abnormality in COMPASS 31 and/or ESC (COMPASS 31 and/or ESC). CAN (≥1 abnormal CART) and confirmed CAN (≥2 abnormal CARTs) were present in 28.1% and 12.5%, DPN (two abnormalities among symptoms, signs, VPT, and TT) in 52%, abnormal COMPASS 31 (total weighted score >16.44) in 48% and abnormal ESC (hands ESC <50 μS and/or feet ESC <70 μS) in 47.4%. Both the patterns-COMPASS 31+ESC and COMPASS 31 and/or ESC-were associated with CAN and DPN (P < .01). COMPASS 31 and ESC reached a sensitivity of 75% and 83% for confirmed CAN, and a specificity of 65% and 67% for DPN. When combining the tests, the sensitivity for CAN rose by up to 100% for CAN and the specificity up to 89% for DPN. The combination of the tests can allow a stepwise screening strategy for CAN, by suggesting CAN absence with combined normality, and prompting to CARTs with combined abnormality.

Self-Reported Depressive Symptoms Might be Associated with Sudomotor Dysfunction in Chinese T2DM Patients.

To determine the relationships of sudomotor functions, nerve conductions and self-reported depressive symptoms in Chinese type 2 diabetes (T2DM) patients. T2DM patients in a single community health center were included in this study. Demographic, medical and laboratory data were collected. Michigan Neuropathy Screening Instrument (MNSI) examination was conducted in all patients. SUDOSCAN test and Point-of-care Nerve Conduction Device (DPN-check) were conducted and all the patients finished the Patient Health Questionnaire-9 (PHQ-9). A total of 162 T2DM patients (74 males and 88 females) were included. The mean age was 69.0±7.2 years and the mean course of diabetes was 10.5±8.0 years with a mean HbA1c level of 7.3±1.4%. Thirty of them (18.5%) had self-reported depressive symptoms (PHQ-9 scores≥5). Diabetic peripheral neuropathy (DPN) was diagnosed according to the MSNI examination in 74 patients. Electrochemical skin conductance (ESC) values of both hands and feet were significantly lower in patients with depressive symptoms (Hands ESC: 60.63±18.92 vs. 67.64±16.02 μS, p<0.05; Feet ESC: 59.60 ± 15.19 vs. 66.19±14.99 μS, p<0.05). The proportion of patients with moderate to severe depressive symptoms were significantly higher in those with ESC values<60 μS (13.33% vs. 3.846%, p<0.05). Hands ESC values were negatively related to PHQ-9 scores (r =- 0.168, p<0.05). After adjusting for variables, hands and feet ESC values remained negatively related with depressive symptoms (β =- 0.036 and-0.038, p<0.05). Female were positively related to depressive symptoms with odds ratio 3.4 (95%CI 1.1-10.5, p<0.05). Self-reported depressive symptoms might be associated with sudomotor dysfunction in Chinese T2DM patients.

The Relationship Between β-cell Function Indices and Sudomotor Function in Chinese Patients with Type 2 Diabetes.

SUDOSCAN, a new non-invasive, quick, sensitive and quantitative technique, has been developed to detect diabetic peripheral neuropathy, and the latter is believed to be correlated with impaired β-cell function. The purpose of the present study was to investigate the associations between β-cell function indices and sudomotor function in Chinese type 2 diabetes. A total of 266 Chinese patients with type 2 diabetes were enrolled. Sudomotor function was assessed using electrochemical skin conductance of hands and feet. Pancreatic β-cell function was determined by homeostasis model assessment of β-cell function index, early-phase β-cell function indices and total β-cell function indices. Pearson correlation analysis and multiple linear stepwise regression analysis were carried out to explore the associations between β-cell function indices and sudomotor function. Patients with lower early-phase β-cell function had lower electrochemical skin conductance levels of hands and feet and higher asymmetry ratio of hands and feet. Both Pearson correlation analysis and multiple linear stepwise regression analysis showed significantly positive relationships between early-phase β-cell function and electrochemical skin conductance levels of hands and feet, after controlling for potential confounders (P<0.05). Impaired early-phase β-cell function was positively associated with sudomotor dysfunction in Chinese patients with type 2 diabetes. We speculated that impaired early-phase β-cell function may be associated with the incidence of sudomotor dysfunction in patients with T2DM.

Non-invasive evaluation of sudomotor function in patients with myasthenia gravis

Myasthenia gravis (MG) is an autoimmune disease associated with antibodies against the nicotinic muscle acetylcholine receptor (AChR) at the neuromuscular junction. Dysautonomia has been previously described in MG. Electrochemical skin conductance (ESC), assessed by Sudoscan®, is a non-invasive method that allows evaluation of sudomotor function. Since sweat glands are innervated by sudomotor, postganglionic, cholinergic sympathetic C-fibers, we hypothesized that ESC could be a reliable method for assessing autonomic dysfunction in MG. ESC measurements were prospectively assessed in patients with generalized MG and in healthy controls. Patients with diabetes mellitus, anticholinergic medication or electrophysiological findings of peripheral neuropathy were excluded. Data regarding demographic and disease features were collected. Presence of autonomic symptoms in patients with MG was assessed by Compass-31. For statistical analysis we performed student t-test and Chi2 test for comparison between both groups. We included 24 patients (mean age of 46.4±10.6, 75% women, mean disease duration 12.5 years, 62.5% positive for AChR antibodies) and 37 controls. We found no difference in either foot (P=0.13) or hand (P=0.83) ESC measurements between patients and controls, even after correcting for age. We could not prove the presence of autonomic sympathetic dysfunction in our cohort of MG patients when assessed by Sudoscan®. In addition, Compass-31 was not a useful questionnaire in this clinical context.

The relationship between sudomotor function and skin microvascular reactivity in individuals with type 1 diabetes of long duration

AimThe aim of this study was to assess the relationship between sudomotor function and microvascular perfusion in patients with type 1 diabetes (DM1). MethodsWe evaluated 415 patients (206 women), with DM1, median age of 41 (IQR: 33–53) years, disease duration of 25 (IQR: 20–32) years. We assessed metabolic control of diabetes and the presence of peripheral and cardiac autonomic neuropathy. Sudomotor function was assessed using Sudoscan device by electrochemical skin conductance (ESC). Microvascular function was measured by laser-Doppler flowmetry with basal perfusion, the peak flow after occlusion (PORHpeak) and THmax which is the percentage change between basal perfusion and the peak flow during thermal hyperemia (TH). The accumulation of advanced glycation end products in the skin was assessed by skin autofluorescence (AF) measurement using AGE Reader. We subdivided patients based on the presence of diabetic peripheral neuropathy (DPN), cardiac autonomic neuropathy (CAN) and according to normal value of ESC. ResultsPatients with abnormal ESC had higher skin AF [2.5 (2.1–2.9) vs 2.1 (1.9–2.5) AU, p < 0.001], lower eGFR [83 (72–96) vs 98 (86–108) ml/min/1.73 m2, p < 0.001], higher basal perfusion [25 (12–81) vs 14 (7–43) PU, p < 0.001], lower THmax [664 (137–1461) vs 1115 (346–1933) %, p = 0.002], higher PORHpeak [104 (59–167) vs 70 (48–135) PU, p < 0.001] as compared to subjects with normal ESC results.We found negative correlation between THmax and TG level (Rs = −0.14, p < 0.005), AF (Rs = −0.19, p = 0.001), vibration perception threshold - VPT (Rs = −0.24, p < 0.001) and positive correlation with HDL level (Rs = 0.14, p = 0.005), Feet ESC (Rs = 0.21, p < 0.001) and Hands ESC (Rs = 0.14, p = 0.004). We found positive correlation between PORHpeak and TG level (Rs = 0.14, p = 0.003), skin AF (Rs = 0.29, p < 0.001), VPT (0.27, p < 0.001) and negative correlation with eGFR (Rs = −0.2, p < 0.001), HDL (Rs = −0.12, p = 0.01), Feet ESC (Rs = −0.27, p < 0.001) and Hand ESC (Rs = −0.16, p = 0.002). ConclusionImpaired microvascular reactivity is associated with sudomotor dysfunction in patients with type 1 diabetes.

T33. Electrochemical skin conductance as a marker of neuropathic pain in hereditary amyloid polyneuropathy related to transthyretin

Neuropathic pain (NP) is one of the most common symptoms of small fiber dysfunction in hereditary amyloid polyneuropathy related to transthyretin (hATTR-FAP), contributing to a poor quality of life in these patients. Despite being a common problem in many neurological conditions, there are few neurophysiological tests with high sensitivity to assess pain, with the notable exception of laser evoked potentials. Electrochemical skin conductance (ESC), measured by Sudoscan©, is a fast and reliable method capable of measuring sudomotor function, tested in various diseases. Since sudomotor function is mediated by post ganglionic sympathetic C fibers, we sought to assess the ESC in hATTR-FAP patients as a predictor of NP. 200 consecutive hATTR V30M amyloidosis patients (104 carriers, 96 symptomatic), with a mean age of 45.5 ± 13.6 years (118 females) were studied. ESC, measured by Sudoscan©, was recorded in both hands and feet. Neuropathy Impairment Scale (NIS) and Body mass index (BMI) were recorded. The presence of NP was evaluated by clinical signs and symptoms, and was graded in a 3 point scale (absent, moderate, severe). Independent-samples T test, One-Way ANOVA and Binary logistic regression were used for comparisons (level of significance set at 0.01). ROC curve analysis were also performed. Both feet and hands ESC were significantly lower in the symptomatic group when compared to carriers (75.8 ± 8.7 vs 38.1 ± 26.5 and 72.2 ± 10.3 vs 56.5 ± 21.2 respectively, p < 0.001). Feet ESC was significantly different between all degrees of NP (74.0 ± 12.9 vs 47.2 ± 27.7 vs 30.2 ± 22.7, p < 0.001), while hands ESC and NIS were only significantly lower in the severe NP group. In the regression model analysis, after adjustment for age, gender, BMI, stage of disease and NIS, feet ESC was a significant independent predictor for the presence of NP (B = 0.955 p = 0.005). The ROC curve of this model showed an area under the curve of 0.958 (p < 0.001). ROC curve analysis of Feet ESC as a predictor of NP showed an area under the curve of 0.850 (p < 0.001). ESC, measured by Sudoscan©, has already been acknowledged as a promising tool for small fiber dysfunction. In this study a clear relationship was demonstrated between NP and ESC values, independent of disease stage or neuropathy degree. ESC is a rapid and noninvasive neurophysiological tool for the evaluation of NP.

Normative Values for Electrochemical Skin Conductance Measurements for Quantitative Assessment of Sudomotor Function in Healthy Indian Adults.

Context:Electrochemical skin conductance (ESC) test is a widely accepted objective technique for quantitatively assessing sudomotor dysfunction, which is one of the earliest-detected neurophysiologic abnormalities in diabetic patients with distal symmetric polyneuropathy.Aims:This study aimed to provide normative data for ESC values among healthy Indian participants and assess the potential influence of age, sex, and body mass index (BMI) on ESC measurements.Settings and Design:A sample of 217 healthy participants aged 18–75 years were recruited and assessed for parameters including age, gender, BMI, and ESC measurements of the hands and feet.Statistical Analysis Used:The Shapiro–Wilk test was used to assess the normality of the data. Pearson's correlation was used to evaluate the association between age, gender, and BMI, and ESC measurements.Results:The mean age of the participants was 43.3 ± 13.2 years, and mean BMI was 26.0 ± 4.3 kg/m2. Mean ESC for the hands and feet was 68.9 ± 13.1 and 71 ± 12.9 micro-Siemens, respectively, and there was a significant correlation between values from the right and left hands and feet (r = 0.9, P < 0.0001). A significant correlation was also observed between ESC measurements of the hands and feet (r = 0.94, P < 0.0001). ESC values of both hands and feet declined with age. A weak but significant inverse correlation between ESC and age was observed for the hands (r = 0.02, P = 0.01) and for the feet (r = 0.12, P < 0.0001). There was no significant difference in hand or feet ESC measurement between male and female participants. No significant correlation was observed between BMI and ESC of hands or feet. Only age was identified as a significant determinant of ESC on multivariate logistic regression analysis.Conclusions:Normative values for Indians are lower than that reported for Caucasians.

P356 Sudoscan as a diagnostic tool for transthyretin familial amyloid polyneuropathy

Objectives Evaluate the diagnostic utility of Sudoscan for transthyretin familial amyloid polyneuropathy (TTR-FAP). Methods One hundred and ten TTR-FAP Val50Met carriers were divided in asymptomatic (group 1), with doubtful neurologic symptoms (group 2) and symptomatic stage 1 with less than 3 years of disease (group 3). We analysed quantitative sensory testing with determination of cold detection thresholds (CDT), heart rate variability (HRV), sympathetic skin responses (SSR), sural sensory nerve action potential (SNAP) and electrochemical skin conductance (ESC) measured by Sudoscan in both hands and feet. Statistical analysis was done using SPSS 24.0. Results Mean age was 35 for group 1, 44 for group 2 and 40 for group 3. Feet and hand ESC were each significantly reduced among symptomatic patients (77 ± 5 vs. 71 ± 12 vs. 53 ± 26 μS p 0.0001). ROC analysis for feet and hand ESC showed area under the curve of 0.84 and 0.76, respectively; p ⩽ 0.0001). Discussion Except for SSR, all neurophysiological measures were statically different between the 3 groups. Both feet and hand ESC demonstrated strong correlation with CDT, HRV and sural SNAP. ROC curve analysis showed significant results for both hand and feet ESC. Conclusions These findings suggest that Sudoscan is a promising diagnostic test for TTR-FAP. Significance Sudoscan should be considered for routine assessment in TTR-FAP Val50Met carriers.

P269 Small fiber assessment by sudoscan in transthyretin familial amyloid polyneuropathy treated patients – A longitudinal study

Objective To prospectively assess small fiber involvement in Transthyretin familial amyloid polyneuropathy (TTR-FAP). Methods We studied 116 TTR-FAP Val30Met subjects (59 asymptomatic carriers, 45 tafamidis-treated, and 12 liver transplanted) at three time (t) points separated by a mean of 12.5(±4.2) and 11.5(±3.2) months between t1–t2 and t2–t3, respectively. Sural nerve action potential (SNAP), palmar and plantar sympathetic skin response (SSR) and electrochemical skin conductance (ESC) measured by Sudoscan in hands and feet were evaluated. Neuropathy Impairment Scale (NIS) and Body mass index (BMI) were recorded. Adjusted generalized linear model repeated measures was used for comparisons (level of significance set at 0.01). Results As expected, sural SNAP, plantar SSR, and feet and hands ESC, were significantly lower in tafamidis and transplanted groups (p Discussion Sudomotor function seems to decline over time among tafamidis-treated patients. Conclusions Small fiber neuropathy progression seems not to be totally halted by tafamidis treatment, as assessed with Sudoscan. Significance Sudoscan appears to be a non-invasive, easy and reproducible test to assess disease progression and treatment effectiveness in TTR-FAP.

Electrochemical Skin Conductance May Be Used to Screen for Diabetic Cardiac Autonomic Neuropathy in a Chinese Population with Diabetes.

Aims. This study aimed to assess whether the electrochemical skin conductance (ESC) could be used to screen for diabetic cardiac autonomic neuropathy (DCAN) in a Chinese population with diabetes. Methods. We recruited 75 patients with type 2 diabetes mellitus (T2DM) and 45 controls without diabetes. DCAN was diagnosed by the cardiovascular autonomic reflex tests (CARTs) as gold standard. In all subjects ESCs of hands and feet were also detected by SUDOSCAN™ as a new screening method. The efficacy was assessed by receiver operating characteristic (ROC) curve analysis. Results. The ESCs of both hands and feet were significantly lower in T2DM patients with DCAN than those without DCAN (67.33 ± 15.37 versus 78.03 ± 13.73, P = 0.002, and 57.77 ± 20.99 versus 75.03 ± 11.41, P < 0.001). The ROC curve analysis showed the areas under the ROC curve were both 0.75 for ESCs of hands and feet in screening DCAN. And the optimal cut-off values of ESCs, sensitivities, and specificities were 76 μS, 76.7%, and 75.6% for hands and 75 μS, 80.0%, and 60.0% for feet, respectively. Conclusions. ESC measurement is a reliable and feasible method to screen DCAN in the Chinese population with diabetes before further diagnosis with CARTs.

Predictors of autonomic neuropathy in rheumatoid arthritis.

Autonomic dysfunction occurs in rheumatoid arthritis (RA). However, the association between the autonomic dysfunction and inflammation has not been investigated in RA. We investigated the relationship between inflammation and ANS function in RA. In this cross-sectional study, 25 RA patients and 25 age and sex-matched healthy controls were recruited. Autonomic function assessed by five cardiovascular reflex tests according to Ewing. Parasympathetic dysfunction established by applying three tests: heart rate response to deep breath (HRD) and standing (HRS) and Valsalva tests. Sympathetic dysfunction examined by applying two tests: BP response to standing and handgrip test. Peripheral sympathetic autonomic function assessed by Sudoscan through measurement of electrochemical skin conductance of hands and feet. Sudoscan investigates the sweat gland activity and used as a surrogate to study the damage of sympathetic sudomotor nerves in neuropathy. It is an indirect assessment tool of sudomotor function. Disease-specific and inflammatory measures (DAS 28, ESR, CRP, TNF-α, IL-6 and IL-1) were determined. RA patients had significantly impaired HRD, HRS, BP response to hand grip and sudomotor function as compared to healthy controls. Pro-inflammatory cytokines were significantly higher in RA as compared to healthy controls (p<0.05). DAS 28 significantly correlated with HRD in RA. ESR significantly correlated with HRD and HRS. TNF-α significantly correlated with HRD, HRS, BP response to standing and sudomotor function. Significant correlation was found between IL-6 and HRS. Seropositive patients had more pronounced CAN and sudomotor dysfunction. Autonomic dysfunction in RA is related to disease activity, seropositivity and pro-inflammatory cytokines.

Quick, non-invasive and quantitative assessment of small fiber neuropathy in patients receiving chemotherapy.

Chemotherapy-induced peripheral neurotoxicity (CIPN) is a common, potentially severe and dose-limiting adverse effect; however, it is poorly investigated at an early stage due to the lack of a simple assessment tool. As sweat glands are innervated by small autonomic C-fibers, sudomotor function testing has been suggested for early screening of peripheral neuropathy. This study aimed to evaluate Sudoscan, a non-invasive and quantitative method to assess sudomotor function, in the detection and follow-up of CIPN. Eighty-eight patients receiving at least two infusions of Oxaliplatin only (45.4%), Paclitaxel only (14.8%), another drug only (28.4%) or two drugs (11.4%) were enrolled in the study. At each chemotherapy infusion the accumulated dose of chemotherapy was calculated and the Total Neuropathy Score clinical version (TNSc) was carried out. Small fiber neuropathy was assessed using Sudoscan (a 3-min test). The device measures the Electrochemical Skin Conductance (ESC) of the hands and feet expressed in microSiemens (µS). For patients receiving Oxaliplatin mean hands ESC changed from 73 ± 2 to 63 ± 2 and feet ESC from 77 ± 2 to 66 ± 3 µS (p < 0.001) while TNSc changed from 2.9 ± 0.5 to 4.3 ± 0.4. Similar results were observed in patients receiving Paclitaxel or another neurotoxic chemotherapy. During the follow-up, ESC values of both hands and feet with a corresponding TNSc < 2 were 70 ± 2 and 73 ± 2 µS respectively while they were 59 ± 1.4 and 64 ± 1.5 µS with a corresponding TNSc ≥ 6 (p < 0.0001 and p = 0.0003 respectively). This preliminary study suggests that small fiber neuropathy could be screened and followed using Sudoscan in patients receiving chemotherapy.

SUDOSCAN: A Simple, Rapid, and Objective Method with Potential for Screening for Diabetic Peripheral Neuropathy.

Clinical methods of detecting diabetic peripheral neuropathy (DPN) are not objective and reproducible. We therefore evaluated if SUDOSCAN, a new method developed to provide a quick, non-invasive and quantitative assessment of sudomotor function can reliably screen for DPN. 70 subjects (45 with type 1 diabetes and 25 healthy volunteers [HV]) underwent detailed assessments including clinical, neurophysiological and 5 standard cardiovascular reflex tests (CARTs). Using the American Academy of Neurology criteria subjects were classified into DPN and No-DPN groups. Based on CARTs subjects were also divided into CAN, subclinical-CAN and no-CAN. Sudomotor function was assessed with measurement of hand and foot Electrochemical Skin Conductance (ESC) and calculation of the CAN risk score. Foot ESC (μS) was significantly lower in subjects with DPN [n = 24; 53.5(25.1)] compared to the No-DPN [77.0(7.9)] and HV [77.1(14.3)] groups (ANCOVA p<0.001). Sensitivity and specificity of foot ESC for classifying DPN were 87.5% and 76.2%, respectively. The area under the ROC curve (AUC) was 0.85. Subjects with CAN had significantly lower foot [55.0(28.2)] and hand [53.5(19.6)] ESC compared to No-CAN [foot ESC, 72.1(12.2); hand ESC 64.9(14.4)] and HV groups (ANCOVA p<0.001 and 0.001, respectively). ROC analysis of CAN risk score to correctly classify CAN revealed a sensitivity of 65.0% and specificity of 80.0%. AUC was 0.75. Both foot and hand ESC demonstrated strong correlation with individual parameters and composite scores of nerve conduction and CAN. SUDOSCAN, a non-invasive and quick test, could be used as an objective screening test for DPN in busy diabetic clinics, insuring adherence to current recommendation of annual assessments for all diabetic patients that remains unfulfilled.

Sudomotor function as a tool for cardiorespiratory fitness level evaluation: comparison with maximal exercise capacity.

Physical inactivity is a modifiable risk factor for cardiovascular (CV) and metabolic disorders. VO2max is the best method to assess cardio-respiratory fitness level but it is poorly adopted in clinical practice. Sudomotor dysfunction may develop early in metabolic diseases. This study aimed at comparing established CV risk evaluation techniques with SUDOSCAN; a quick and non-invasive method to assess sudomotor function. A questionnaire was filled-in; physical examination and VO2max estimation using a maximal test on a bicycle ergometer were performed on active Finish workers. Hand and foot electrochemical skin conductance (ESC) were measured to assess sudomotor function. Subjects with the lowest fitness level were involved in a 12 month training program with recording of their weekly physical activity and a final fitness level evaluation. Significant differences in BMI; waist and body fat were seen according to SUDOSCAN risk score classification. Correlation between the risk score and estimated VO2max was r = −0.57, p < 0.0001 for women and −0.48, p < 0.0001 for men. A significant increase in estimated VO2max, in hand and foot ESC and in risk score was observed after lifestyle intervention and was more important in subjects with the highest weekly activity. SUDOSCAN could be used to assess cardio-metabolic disease risk status in a working population and to follow individual lifestyle interventions.