Curr Diab Rep. 2013 Aug;13(4):517-32. doi: 10.1007/s11892-013-0392-x.
Neurovascular function and sudorimetry in health and disease.
Vinik AI1, Nevoret M, Casellini C, Parson H.
In this review of thermoregulatory function in health and disease, we review the basic mechanisms controlling skin blood flow of the hairy and glabrous skin and illustrate the major differences in blood flow to glabrous skin, which is, in essence, sympathetically mediated, while hairy skin is dependent upon neuropeptidergic signals, nitric oxide, and prostaglandin, among others. Laser Doppler methods of quantification of blood flow–in response to iontophoresis of acetylcholine or heat–and nociceptor-mediated blood flow have relatively uniformly demonstrated an impaired capacity to increase blood flow to the skin in diabetes and in its forerunners, prediabetes and the metabolic syndrome. This reduced capacity is likely to be a significant contributor to the development of foot ulcerations and amputations in diabetes, and means of increasing blood flow are clearly needed. Understanding the pathogenic mechanisms is likely to provide a means of identifying a valuable therapeutic target. Thermoregulatory control of sweating is intimately linked to the autonomic nervous system via sympathetic C fibers, and sweat glands are richly endowed with a neuropeptidergic innervation. Sweating disturbances are prevalent in diabetes and its precursors, and quantification of sweating may be useful as an index of diagnosis of somatic and, probably, autonomic dysfunction. Moreover, quantifying this disturbance in sweating by various methods may be useful in identifying the risk of progression from prediabetes to diabetes, as well as responses to therapeutic intervention. We now have the technological power to take advantage of this physiological arrangement to better understand, monitor, and treat disorders of small nerve fibers and the somatic and autonomic nervous system (ANS). Newer methods of sudomotor function testing are rapid, noninvasive, not technically demanding, and accessible to the outpatient clinic. Whether the potential applications are screening for diabetes, following poorly controlled diabetes subjects during alteration of their treatment regimen, or simply monitoring somatic and autonomic function throughout the course of treatment, sudorimetry can be an invaluable tool for today’s clinicians.
2.Gordon Smith et al, The diagnostic utility of Sudoscan for distal symmetric peripheral neuropathy. Journal of Diabetes and Its Complications2014; 28: 511–516
J Diabetes Complications. 2014 Jul-Aug;28(4):511-6.
The diagnostic utility of Sudoscan for distal symmetric peripheral neuropathy.
Smith AG1, Lessard M2, Reyna S2, Doudova M2, Singleton JR2.
Diagnosis of early distal symmetric polyneuropathy (DSP) is challenging. Nerve conduction studies (NCS) are often normal. Skin biopsy for intraepidermal nerve fiber density (IENFD) has better sensitivity, but is invasive. Sudoscan is a novel technology that measures electrochemical skin conductance (ESC; microSiemens, μS), which is thought to be proportionate to the number of functional sweat glands. This study evaluatedSudoscan’s diagnostic utility for DSP.
55 patients with suspected DSP (22 with diabetes, 2 prediabetes, 31 idiopathic) and 42 controls underwent the Utah Early NeuropathyScale (UENS) and Sudoscan. Each was offered skin biopsy. DSP participants underwent quantitative sudomotor axon reflex testing (QSART) and NCS.
Feet and hands ESCs were reduced among DSP participants compared to controls (64±22 vs. 76±14 μS p<0.005, and 58±19 vs. 66±18 μS p<0.04). There was no difference between diabetic and idiopathic DSP. Receiver operating characteristic curve analysis revealed feet ESC and IENFD had similar areas under the curve (0.761 and 0.752). ESC correlated with Sural amplitude (0.337, p<0.02), UENS (-0.388, p<0.004), and MNSI (-0.398, p<0.005).
Sudoscan is a promising diagnostic test for diabetic and idiopathic DSP, with diagnostic performance similar to IENFD.
Copyright © 2014 Elsevier Inc. All rights reserved.
Diabetes; Peripheral neuropathy; Skin biopsy; Sudomotor
3.Yajnik et al. Screening of cardiovascular autonomic neuropathy in patients with diabetes using non-invasive quick and simple assessment of sudomotor function. Diabetes & Metabolism. 2013;39(2):126-131
Diabetes Metab. 2013 Apr;39(2):126-31.
Screening of cardiovascular autonomic neuropathy in patients with diabetes using non-invasive quick and simpleassessment of sudomotor function.
Yajnik CS1, Kantikar V, Pande A, Deslypere JP, Dupin J, Calvet JH, Bauduceau B.
Cardiovascular autonomic neuropathy (CAN) is a common but often overlooked complication of diabetes. Sympathetic C-fibers innervating sweat glands can be impaired early on in patients with diabetes. In this study, SUDOSCAN, a new non-invasive device that assesses sudomotor functionwas compared to methods generally used for the investigation of CAN.
A total of 232 patients with diabetes were measured for heart rate variability (HRV) at rest and during moderate activity. Time and frequency domain analysis techniques, including measurement of the low-frequency (LF) domain component, were assessed during HRV testing. Ewing tests, as recommended by the French Health Authority, were also done. Electrochemical sweat conductance (ESC) was measured on the hands and feet, and a risk-score was calculated.
Using two abnormal Ewing tests as a reference for the area under the curve (AUC) of the receiver operating characteristics (ROC) curve for SUDOSCAN, the risk-score was 0.74, with a sensitivity of 92% and specificity of 49% for a risk-score cut-off value of 35%. For the ROC curve analysis using the LF power component during moderate activity at a threshold of 90 ms(2) (first quartile) as reference, the AUC was higher for the SUDOSCAN risk-score (0.77) compared with the standard Ewing tests [E:I ratio (0.62), 30:15 ratio (0.76) and blood pressure change on standing (0.55)]. Using a cut-off value of 35%, risk-score sensitivity and specificity were 88 and 54%, respectively.
SUDOSCAN, which allows quick quantitative assessment of sudomotor function, may be used for early screening of CAN in everyday clinical practice before resorting to the more sophisticated and specific, but ultimately more time-consuming, Ewing tests.
Copyright © 2012 Elsevier Masson SAS. All rights reserved.
4.Calvet JH et al, Assessment of small fiber neuropathy through a quick, simple and non invasive method in a German diabetes outpatient clinic. Exp Clin Endocrinol Diabetes. 2013 Feb;121(2):80-3
Exp Clin Endocrinol Diabetes. 2013 Feb;121(2):80-3.
Assessment of small fiber neuropathy through a quick, simple and non invasive method in a German diabetesoutpatient clinic.
Calvet JH1, Dupin J, Winiecki H, Schwarz PE.
Sudomotor dysfunction is one of the earliest neurophysiologic abnormalities to manifest in distal small fiber neuropathy. SUDOSCAN® was developed to provide a non invasive, quick, simple and quantitative measurement of sweat function. The aim of this observational study was to assess sweat function in a diabetes outpatient consult clinic in Germany.
The study was conducted from February 2009 to March 2011 on patients of a diabetes outpatient clinic in Germany with type 1 and type 2 diabetes, and was conducted parallel to standard care. Sweat function was evaluated by measuring the electrochemical conductance (ESC) of the hands and feet. The method’s reproducibility between 2 devices and a follow-up according to insulin administration were also assessed.
52 patients with type 1 diabetes and 115 patients with type 2 diabetes (69 receiving insulin) were involved in this observational study. Hand and foot conductances were lower in patients with type 2 diabetes when compared to patients with type 1 diabetes. A slight decrease in hand and foot conductances was observed in patients with type 2 diabetes without insulin, while an increase was observed in patients receiving insulin (-3.8±9.7 vs. 1.0±9.7 µS, p=0.02 for the hands and -2.2±7.5 vs. 4.1±8.8 µS, p<0.001 for the feet). Coefficient of correlation between measurements performed with the 2 different devices was 0.85 for hands and 0.93 for feet, p<0.001. No safety concern was reported and none of the subjects experienced discomfort during the tests.
This preliminary study shows that the assessment of small C fiber neuropathy can be performed non invasively, quickly and effectively in standard diabetes outpatient practice with very good reproducibility. The observation that electrochemical skin conductance improves with intensified insulin treatment must be confirmed in a clinical study performed on a larger population.
5.Yajnik CS et al, Quick and simple evaluation of sudomotor function for screening of diabetic neuropathy.ISRN Endocrinol. 2012;2012:103714.
International Scholarly Research Network(ISRN) Endocrinology 2012; Volume 2012, Article ID 103714, 7 pages.
Quick and Simple Evaluation of Sudomotor Function for Screening of Diabetic Neuropathy.
Chittaranjan S. Yajnik,1 Vaishali V. Kantikar,1 Amol J. Pande,1 and Jean P. Deslypere2
Objective. The aim of this study was to compare SUDOSCAN, a new device to evaluate sweat function (reflecting peripheral small C-fiber status), with conventional measures of peripheral and cardiac neuropathy in patients with type 2 diabetes. Methods. 265 diabetic patients were tested for symptoms and clinical signs of neuropathy using Michigan Neuropathy Screening Instrument
(MNSI), vibration perception threshold (VPT) using biothesiometer, and cardiac autonomic neuropathy (CAN) using Ewing’s protocol. Sudomotor function was investigated with SUDOSCAN through measurement of electrochemical skin conductance (ESC) of hands and feet. Lower ESC is suggestive of sudomotor dysfunction. Results. Lower ESC at feet was significantly associated both with increasing symptoms (MNSI A) and increasing score on physical abnormalities (MNSI B). Lower ESC at feet was also significantly associated with increasing VPT by biothesiometry (P < 0.01), and with higher number of abnormal CAN results (P < 0.05). ESC was associated with postural fall in blood pressure (sympathetic abnormality) (P < 0.05), but not with heart rate variability (HRV) tests (parasympathetic abnormalities). Conclusions. Sudomotor dysfunction testing may be a simple test to alert physicians to peripheral nerve and cardiac sympathetic dysfunction. Ease of performance could make it useful in a busy diabetic clinic. Further studies with hard clinical outcomes are indicated.
6.Gin H et al, Non-invasive and quantitative assessment of sudomotor function for peripheral diabetic neuropathy evaluation.Diabetes Metab. 2011 Dec;37(6):527-32.
Non-invasive and quantitative assessment of sudomotor function for peripheral diabetic neuropathy evaluation.
Gin H1, Baudoin R, Raffaitin CH, Rigalleau V, Gonzalez C.
Perturbation of pain sensation is considered one of the major initiating risk factors for diabetic foot ulcer. Sweat dysfunction leading to abnormal skin conditions, including dryness and fissures, can increase foot ulcer risk. The aim of this study was to evaluate Sudoscan™, a new, quick, non-invasive and quantitative method of measuring sudomotor dysfunction as a co-indicator of the severity of diabetic polyneuropathy (DPN).
A total of 142 diabetic patients (age 62±18 years, diabetes duration 13±14 years, HbA(1c) 8.9±2.5%) were measured for vibration perception threshold (VPT), using a biothesiometer, and for sudomotor dysfunction, using electrochemical sweat conductance (ESC) based on the electrochemical reaction between sweat chloride and electrodes in contact with the hands and feet. Retinopathy status was also assessed, as well as reproducibility between two ESC measurements and the effect of glycaemia levels.
ESC measurements in the feet of patients showed a descending trend from 66±17 μS to 43±39 μS, corresponding to an ascending trend in VPT threshold from <15 V to >25 V (P=0.001). Correlation between VPT and ESC was -0.45 (P<0.0001). Foot ESC was lower in patients with fissures, while VPT was comparable. Both VPT and foot ESC correlated with retinopathy status. Bland-Altman plots indicated good reproducibility between two measurements, and between low and high glycaemia levels.
Sudoscan™ is a reproducible technique with results that are not influenced by blood glucose levels. Sweating status may be aquantitative indicator of the severity of polyneuropathy that may be useful for the early prevention of foot skin lesions.
7.Eranki VG et al, Sudomotor function assessment as a screening tool for microvascular complications in type 2 diabetes. Diabetes Res Clin Pract. 2013 Sep;101(3):e11-3.
Diabetes Res Clin Pract. 2013 Sep;101(3):e11-3.
Sudomotor function assessment as a screening tool for microvascular complications in type 2 diabetes.
Eranki VG1, Santosh R, Rajitha K, Pillai A, Sowmya P, Dupin J, Calvet JH.
Sudoscan, a non invasive, quick, and simple method to measure sweat function, was evaluated as a screening tool for microvascular complications intype 2 diabetes. AUC of the ROC curve for detection of microvascular complication was 0.75 for an autonomic risk score, with a sensitivity of 82% and a specificity of 61%.
Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.
Nephropathy; Peripheral neuropathy; Retinopathy; Small C-fiber
8.Freedman BI et al,Relationships between electrochemical skin conductance and kidney disease in Type 2 diabetes.J Diabetes Complications. 2014 Jan-Feb;28(1):56-60.
J Diabetes Complications. 2014 Jan-Feb;28(1):56-60.
Relationships between electrochemical skin conductance and kidney disease in Type 2 diabetes.
Freedman BI1, Bowden DW2, Smith SC3, Xu J3, Divers J4.
SUDOSCAN® non-invasively measures peripheral small fiber and autonomic nerve activity using electrochemical skin conductance. Since neuropathy and nephropathy are microvascular Type 2 diabetes (T2D) complications, relationships between skin conductance, estimated glomerular filtration rate (eGFR), and urine albumin:creatinine ratio (UACR) were assessed.
Two hundred five African Americans (AA) with T2D, 93 AA non-diabetic controls, 185 European Americans (EA) with T2D, and 73 EA non-diabetic controls were evaluated. Linear models were fitted stratified by population ancestry and T2D, adjusted for covariates.
Relative to EA, AA had lower skin conductance (T2D cases p<0.0001; controls p<0.0001). Skin conductance was also lower in T2D cases vs. controls in each population (p<0.0001, AA and EA). Global skin conductance was significantly associated with eGFR in AA and EA with T2D; adjusting for age, gender, BMI, and HbA1c, positive association was detected between skin conductance and eGFR in AA T2D cases (parameter estimate 3.38, standard error 1.2; p=5.2E(-3)), without association in EA T2D cases (p=0.22).
Noninvasive measurement of skin conductance strongly associated with eGFR in AA with T2D, replicating results in Hong Kong Chinese. SUDOSCAN® may prove useful as a low cost, non-invasive screening tool to detect undiagnosed diabetic kidney disease in populations of African ancestry.
African Americans; Diabetes; Kidney disease; Neuropathy; Skin conductance
ExpClinEndocrinol Diabetes2013; 121: 1–5
Non-invasive Screening of Diabetes Risk by AssessingAbnormalities of Sudomotor Function.
G. Müller 1 , J. Olschewski 1 , T. Stange 1 , S. Bornstein 1 , P. E. H. Schwarz 1 , 2
9.Ozaki.R, A new tool to detect kidney disease in Chinese type 2 diabetes patients: comparison of EZSCAN with standard screening methods. Diabetes Technol Ther. 2011 Sep;13(9):937-43.
A New Tool to Detect Kidney Disease in Chinese Type 2 Diabetes Patients—Comparison of EZSCAN with Standard Screening Methods.
Risa Ozaki, MBChB, MRCP,1 Kitty K.T. Cheung, MBChB, MRCP,1 Enoch Wu, MBChB, MRCP,1
Alice Kong, MBChB, FRCP,1 Xilin Yang, Ph.D.,1 Eric Lau, MPhil,1
Philippe Brunswick, Ph.D.,2 Jean-Henri Calvet, Ph.D.,2
Jean-Paul Deslypere, M.D.,2 and Juliana C.N. Chan, M.D., FRCP1
Background: EZSCAN (Impeto Medical, Paris, France), a noninvasive device that assesses sweat gland dysfunction using reverse iontophoresis, also detects early dysglycemia. Given the interrelationships among dysglycemia, vasculopathy, and neuropathy, EZSCAN may detect kidney disease in diabetes (DKD).
Methods: An EZSCAN score (0–100) was calculated using a proprietary algorithm based on the chronoamperometry analysis. We measured the score in 50 Chinese type 2 diabetes patients without DKD (urinary albumin–creatinine ratio [ACR] < 2.5mg/mmol in men or ACR < 3.5mg/mmol in women and estimated glomerular filtration rate [eGFR] > 90mL/min/1.73m2) and 50 with DKD (ACR ‡ 25mg/mmol and eGFR < 60mL/min/1.73m2). We used spline analysis to determine the threshold value of the score in detecting DKD and its sensitivity and specificity.
Results: EZSCAN scores were highly correlated with log values of eGFR (r = 0.67, P < 0.0001) and ACR (r = – 0.66, P < 0.0001). Using a cutoff value of 55, the score had 94% sensitivity, 78% specificity, and a likelihood ratio of 4.2 to detect DKD with a positive predictive value of 81% and a negative predictive value of 93%. On multivariable analysis, DKD was independently associated with EZSCAN score (b= -0.72, P = 0.02), smoking status (1 = never, 0 = current/former) (b= -2.37, P = 0.02), retinopathy (1 = yes, 0 = no) (b = 3.019, P = 0.01), triglycerides (b = 2.56, P = 0.013), and blood hemoglobin (b= -0.613, P = 0.04). Patients without DKD but low EZSCAN score (n = 10) had longer duration of disease (median [interquartile range], 13 [9–17] vs. 8 [4–16] years; P = 0.017) and were more likely to have retinopathy (36.7% vs. 5.1%, P = 0.02), lower eGFR (98 [95.00–103] vs. 106[98.5–115], P = 0.036), and treatment with renin–angiotensin system blockers (81.8% vs. 25.6%, P = 0.002) than those with a normal score.
Conclusion: EZSCAN may detect high-risk subjects for DKD in Chinese populations.
10.Raisanen A et al, Sudomotor function as a tool for cardiorespiratory fitness level evaluation: comparison with maximal exercise capacity.Int J Environ Res Public Health. 2014 May 30;11(6):5839-48.
Int J Environ Res Public Health. 2014 May 30;11(6):5839-48.
Sudomotor function as a tool for cardiorespiratory fitness level evaluation: comparison with maximal exercisecapacity.
Raisanen A1, Eklund J2, Calvet JH3, Tuomilehto J4.
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 lowestfitness 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.
11.Ashit Syngle et al, Disease-modifying anti-rheumatic drugs improve autonomic neuropathy in arthritis: DIANA study. Clin Rheumatol. 2014 Jun 15.
Clin Rheumatol. 2014 Jun 15. [Epub ahead of print]
Disease-modifying anti-rheumatic drugs improve autonomic neuropathy in arthritis: DIANA study.
Syngle A1, Verma I, Krishan P, Garg N, Syngle V.
Autonomic neuropathy (AN) is a risk predictor for sudden cardiac death in rheumatoid arthritis (RA) and ankylosing spondylitis (AS). However, the impact of most commonly employed disease-modifying anti-rheumatic drug (DMARD) therapy on autonomic neuropathy in rheumatic diseases is not known. Hence, we investigated the efficacy of DMARDs on autonomic neuropathy in RA and AS. We performed autonomic function assessment in 60 patients in this open-label, 12-week pilot study including 42 patients with RA, 18 with AS, and 30 aged-matched healthy subjects. The methodology included assessment of cardiovascular autonomic reflex tests according to Ewing. Parasympathetic dysfunction was established by performing three tests: heart rate response to deep breathing, standing, and Valsalva tests. Sympathetic dysfunction was examined by applying two tests: blood pressure response to standing and handgrip tests. Sudomotor function was assessed by Sudoscan. Cardiovascular reflex tests were impaired significantly among the patients as compared to healthy subjects (p < 0.05). Autonomic neuropathy was more pronounced in biologic-naive RA and AS patients. After treatment with combination synthetic DMARDs, parasympathetic, and sudomotor dysfunction significantly (p < 0.05) improved in RA and AS. Biologic DMARDs significantly improved parasympathetic, sympathetic and peripheral sympathetic autonomic neuropathy (p < 0.05) in biologic-naive RA and AS patients. In conclusion, synthetic DMARDs improved parasympathetic and sudomotor dysfunction in both DMARD-naive RA and AS patients. However, biologic DMARDs improved parasympathetic, sympathetic and sudomotor dysfunction to a greater extent than synthetic DMARDs in both RA and AS patients.
12.Dominique Hubert, et al,Abnormal electrochemical skin conductance in cystic fibrosis.Journal of Cystic Fibrosis 2011；10 (1)：15–20
Journal of Cystic Fibrosis 2011；10 (1)：15–20
Abnormal electrochemical skin conductance in cystic fibrosis.
Dominique Hubert, Philippe Brunswick, Jean-Henri Calvet, Daniel Dusser, Isabelle Fajac
Background: Electrochemical skin conductance measurement is an active electrophysiologic method in which incremental low direct voltage is applied on the skin. It generates a current due to reverse iontophoresis which previous studies suggested to be mostly related to chloride anion movements. As sweat chloride movements upon electric stimulation were likely to be impaired in cystic fibrosis (CF) patients, we designed a proof-of-concept study to measure electrochemical skin conductance in CF patients and control subjects and to test the ability of this method to discriminate CF from controls.
Methods: Electrochemical skin conductance was measured in 41 adult patients with classical CF and 20 healthy control subjects. Patients placed their hands and feet on nickel electrodes and an incremental low direct voltage was applied on the anode during 2 min. The resulting voltage on the cathode and the current generated between anode and cathode were measured and from them, two electrochemical skin conductance variables were calculated: ESC, obtained when a low voltage of 1.6 V was applied, and dESC which took into account electrochemical skin conductances obtained when low and high voltages were applied.
Results: ESC measurements on hands and feet were significantly different in CF patients (on feet: 75±10 μSi), as compared with control subjects (62±13 μSi, p<0.0001); dESC was also significantly different and more discriminative in CF patients (on feet: 34±24 μSi), as compared with control subjects (93±24 μSi, p<0.0001). dESC measurement provided a diagnostic specificity of 1 and a sensitivity of 0.93.
Conclusions: These results show that electrochemical skin conductance which is easily and rapidly measured is abnormal in CF patients.
13.Aaron I. Vinik et al, Sudoscan, noninvasive tool for detecting diabetic small fiber neuropathy and
autonomic dysfunction. Diabetes Technol Ther. 2013 Nov;15(11):948-53.
Diabetes Technol Ther. 2013 Nov;15(11):948-53.
Sudoscan, a noninvasive tool for detecting diabetic small fiber neuropathy and autonomic dysfunction.
Casellini CM1, Parson HK, Richardson MS, Nevoret ML, Vinik AI.
Sudomotor dysfunction may be an early detectable abnormality in diabetic small fiber neuropathy. The aim of this study was to evaluate the efficacy of Sudoscan™ (Impeto Medical, Paris, France) in detecting diabetic neuropathy (DN), in comparison with other standardized tests, in patients with diabetes mellitus (DM).
SUBJECTS AND METHODS:
Sudoscan measures electrochemical skin conductance (ESC) of hands and feet through reverse iontophoresis. We evaluated 83 DM patients with and without DN and 210 healthy controls (HCs). Neuropathy Impairment Score-Lower Legs (NIS-LL), quantitativeautonomic function testing (QAFT), and quantitative sensory testing (QST) were performed. Symptomatic pain was recorded using a visual analog scale. Receiver-operator characteristic (ROC) curves were calculated to evaluate the efficacy of Sudoscan in detecting DN compared with traditional modalities.
Diabetes patients with DN had significantly worse ESCs of feet and hands than DM patients without DN and HCs (respectively, 56.3±3 vs. 75.9±5.5 and 84.4±0.9 （P<0.0001） for feet and 51.9±2.4 vs. 67.5±4.3 and 73.1±0.8 （P<0.0001） for hands). Increasing NIS-LL scores were associated with decreasing ESC values. ESCs correlated significantly with clinical (NIS-LL), somatic (QST), and autonomic (QAFT) measures of neuropathy and with pain scores. ROC curve analysis showed significant results for both hands and feet ESC (area under the curve of 0.86 and 0.88, respectively; P<0.0001) with sensitivity of 78% and specificity of 92% for feet to detect DN.
Sudoscan is a promising, sensitive tool to detect neuropathy in patients with DM. This is a very simple, easy-to-perform test that can be done in the clinical setting in 3-5 min