Evaluation of sural nerve automated nerve conduction study in the diagnosis of peripheral neuropathy in patients with type 2 diabetes mellitus

Glycemic variability is associated with sural nerve conduction velocity in outpatients with type 2 diabetes: Usefulness of a new point-of-care device for nerve conduction studies

AIMS/INTRODUCTION

Although several studies have shown the association between continuous glucose monitoring (CGM)-derived glycemic variability (GV) and diabetic peripheral neuropathy, no studies have focused on outpatients or used NC-stat®/DPNCheck™, a new point-of-care device for nerve conduction study (NCS). We investigated the association between CGM-derived GV and NCS using DPNCheck™ in outpatients with type 2 diabetes, and further analyzed the difference in results between patients with and without well-controlled HbA1c levels.

MATERIALS AND METHODS

All outpatients with type 2 diabetes using the CGM device (FreeStyle Libre Pro®) between 2017 and 2022 were investigated. Sural nerve conduction was evaluated by sensory nerve action potential (SNAP) amplitude and sensory conduction velocity (SCV) using DPNCheck™. Associations of CGM-derived GV metrics with SNAP amplitude and SCV were investigated.

RESULTS

In total, 304 outpatients with type 2 diabetes were included. In a linear regression model, most CGM-derived GV metrics except for the mean amplitude of glucose excursion and low blood glucose index were significantly associated with SCV, but not with SNAP amplitude. The significant associations of most CGM-derived GV metrics with SCV remained after adjustment for possible confounding factors, but not after adjustment for glycated hemoglobin (HbA1c). Most CGM-derived GV metrics were significantly associated with SCV after adjustment for HbA1c in patients with a HbA1c ≤ 6.9%, but not in those with a HbA1c ≥ 7.0%.

CONCLUSIONS

In outpatients with type 2 diabetes, multiple CGM-derived GV metrics were significantly associated with SCV obtained by DPNCheck™. GV may have independent impacts on peripheral nerve function, particularly in patients with well-controlled HbA1c levels.

Sheffield One-Stop Service: A potential model to improve the screening uptake of diabetic peripheral neuropathy and other microvascular complications of diabetes

The world is experiencing an enormous rise in the prevalence of diabetes, which is associated with massive healthcare costs that threaten to overwhelm many healthcare systems. Most of the diabetes expenditure is attributed to the management of chronic diabetes complications, including diabetic peripheral neuropathy (DPN)/diabetic foot complications, chronic kidney disease, sight-threatening retinopathy and cardiovascular diseases. Of these complications, the most overlooked is DPN. Most consultations around the world do not even involve taking off shoes and socks to carry out a foot examination, and even when carried out, the peripheral neurological examination using the 10-g monofilament diagnoses DPN when it is already at an advanced stage. Thus, all too often diabetes complications are diagnosed late, resulting in devastating outcomes, particularly in low- to middle-income countries. There is, therefore, an urgent need to instigate new strategies to improve microvascular screening uptake using a holistic protocol for annual diabetes health checks outside the busy diabetes clinic. One such approach, the Sheffield One-Stop Microvascular Screening Service, which involves modern point of care devices to diagnose DPN, has been shown to be feasible and effective, resulting in high uptake and early management of diabetes complications. This article outlines the advantages of this One-Stop Microvascular Screening Service and a plan to trial an adapted version of this service to a resource-limited country, the Philippines. If successful, this model has the potential for implementation in other countries around the world.

Assessment of neuropathy subtypes in type 1 diabetes

INTRODUCTION

Diabetic polyneuropathy (DPN), a common complication of diabetes, can manifest as small, large, or mixed fiber neuropathy (SFN, LFN, and MFN, respectively), depending on the type of fibers involved. Despite evidence indicating small fiber involvement prior to large fiber involvement in type 1 diabetes mellitus (T1DM)-associated DPN, no evidence has been produced to determine the more prevalent subtype. We aim to determine the more prevalent type of nerve fiber damage-SFN, LFN, and MFN-in T1DM-associated DPN, both with and without pain.

RESEARCH DESIGN AND METHODS

In this cross-sectional study, participants (n=216) were divided into controls; T1DM; T1DM with non-painful DPN (NP-DPN); and T1DM with painful DPN (P-DPN). DPN was further subgrouped based on neuropathy severity. The more prevalent type of fiber damage was determined applying small and large fiber-specific tests and three diagnostic models: model 1 (≥1 abnormal test); model 2 (≥2 abnormal tests); and model 3 (≥3 abnormal tests).

RESULTS

MFN showed the highest prevalence in T1DM-associated DPN. No differences in neuropathy subtype were found between NP-DPN and P-DPN. DPN, with prevalent SFN plateaus between models 2 and 3. All models showed increased prevalence of MFN according to DPN severity. Model 3 showed increased DPN with prevalent LFN in early neuropathy. DPN with prevalent SFN demonstrated a similar, but non-significant pattern.

CONCLUSIONS

DPN primarily manifests as MFN in T1DM, with no differentiation between NP-DPN and P-DPN. Additionally, we propose model 2 as an initial criterion for diagnosing DPN with a more prevalent SFN subtype in T1DM. Lastly, the study suggests that in mild stages of DPN, one type of nerve fiber (either small or large) is more susceptible to damage.

Reliability of a novel point of care device for monitoring diabetic peripheral neuropathy

We aimed to assess DPNCheck's reliability for repeated sural nerve conduction (NC) parameters. This post hoc analysis used data from the randomized controlled ACUDPN trial assessing NC of the N. Suralis every eight weeks over a 6-month period in 62 patients receiving acupuncture against diabetic peripheral neuropathy (DPN) symptoms. The reliability of DPNCheck for nerve conduction velocity and amplitude was assessed using intraclass correlation coefficients (ICC) and was calculated using data from single time points and repeated measures design. The results of the NC measurements were correlated with the Total Neuropathy Score clinical (TNSc). Overall, for both nerve velocity and amplitude, the reliability at each measurement time point can be described as moderate to good and the reliability using repeated measures design can be described as moderate. Nerve velocity and amplitude showed weak correlation with TNSc. DPNCheck's reliability results question its suitability for monitoring DPN's progression. Given the limitation of our analysis, a long-term, pre-specified, fully crossed study should be carried out among patients with DPN to fully determine the suitability of the device for DPN progression monitoring. This was the first analysis assessing the reliability of the DPNCheck for DPN progression monitoring using data from multiple collection time points.

A Comparison of Self-reported Pain Measures Between Sensory Phenotypes in HIV-associated Sensory Neuropathy

Painful HIV-associated neuropathy (HIV-SN) is a prevalent co-morbidity of HIV infection. Sensory phenotyping, using quantitative sensory testing (QST) could allow for improved stratification to guide personalized treatment. However, previous methods of QST interpretation have demonstrated limited association with self-reported pain measures. This study sought to identify differences in self-reported pain measures between composite QST-derived sensory phenotypes, and to examine any differences in participants reporting multi-site, multi-etiology chronic pain. In this cross-sectional observational study of participants with HIV (n = 133), individuals were allocated to neuropathy and neuropathic pain groups through clinical assessment and nerve conduction testing. They completed symptom-based questionnaires and underwent standardized QST. Participants were assigned, by pre-determined algorithm, to a QST-derived sensory phenotype. Symptoms were compared between sensory phenotypes. Symptom characteristics and Neuropathic Pain Symptom Inventory scores differed between QST-derived sensory phenotypes: 'sensory loss' was associated with more paroxysmal and paraesthetic symptoms compared to 'thermal hyperalgesia' and 'healthy' phenotypes (P = .023-0.001). Those with painful HIV-SN and additional chronic pain diagnoses were more frequently allocated to the 'mechanical hyperalgesia' phenotype compared to those with painful HIV-SN alone (P = .006). This study describes heterogeneous sensory phenotypes in people living with HIV. Differences in self-reported pain outcomes between sensory phenotypes has the potential to guide future stratified trials and eventually more targeted therapy. PERSPECTIVE: This article presents quantitative sensory testing derived phenotypes, thought to reflect differing pathophysiological pain mechanisms and relates them to self-reported pain measures in people with HIV infection. This could help clinicians stratify patients to individualize analgesic interventions more effectively.

Skin advanced glycation end products as a screening tool of neuropathy in type 2 diabetes mellitus

AIM OF THE STUDY

To examine the diagnostic utility of skin advanced glycation end products (AGEs) as screening tool of neuropathy in type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

We included 132 participants (88 men) with a mean age of 64.57 years and median T2DM duration of 14.5 years. Skin AGEs were measured with AGE reader mu connect (Diagnoptics) on the dominant arm and were interpreted as normal vs. elevated. Distal sensorimotor polyneuropathy (DSPN) was diagnosed by the Neuropathy Disability Score. Cardiovascular autonomic neuropathy (CAN), sympathetic and parasympathetic nervous system impairment were diagnosed by cardiovascular autonomic reflex tests.

RESULTS

For DSPN, AGEs yielded high sensitivity (82.8%) and NPV (80.4 %) with moderate specificity (55.4 %). For CAN, they yielded relatively high sensitivity (75.0 %) and NPV (74.5 %) with low specificity (48.7 %). For sympathetic nervous system impairment, AGEs yielded relatively high sensitivity (75.0 %) and high NPV (84.3 %) with low specificity (43.9 %). For parasympathetic nervous system impairment, they yielded high PPV (81.0 %) with moderately high sensitivity (66.7 %) and moderate specificity (55.9 %).

CONCLUSIONS

In a simplified approach, skin AGEs may be used as a screening tool of DSPN and CAN (including sympathetic and parasympathetic nervous system impairment) in T2DM.

Effectiveness of Semmes Weinstein 10 gm monofilament in diabetic peripheral neuropathy taking nerve conduction and autonomic function study as reference tests

Context

Diabetic peripheral neuropathy (DPN) if detected early can reduce the burden on the health system and prevent the development of diabetic foot ulcers and amputation.

Aim

To study the effectiveness of Semmes Weinstein 10 gm monofilament in detecting DPN taking nerve conduction studies (NCS) and autonomic function testing (AFT) as reference tests.

Settings and Design

Observational and comparative cross-sectional study conducted in the Physiology department AIIMS, Bhopal in collaboration with the Medicine department of the institute.

Methods and Material

A total of 72 diagnosed type-2 diabetes mellitus patients were examined using Semmes Weinstein 10 gm monofilament, DPN was confirmed using NCS (Nihon Kohden Neuropack XI machine) and autonomic neuropathy was confirmed using AFT (Ewing's battery and Power lab) with heart rate variability (HRV). Diagnostic value of Semmes Weinstein 10 gm monofilament taking NCS and AFT as reference test was calculated.

Statistical Analysis Used

Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) were calculated using the standard formula.

Results

Sensitivity, specificity, PPV, and NPV using monofilament are 69.23%, 20%, 69.23% and 20% respectively taking NCS as reference test and 70.59%, 0, 92.30%, and 0 respectively taking AFT as reference test.

Conclusions

Semmes Weinstein 10 gm monofilament is not the ideal screening test for the diagnosis of DPN. Sole clinical use of monofilament should be discouraged.

Point-of-care sural nerve conduction could predict the presence of cardiovascular autonomic neuropathy in type 1 diabetes mellitus

AIMS

Assessment for cardiovascular autonomic neuropathy (CAN) in patients with type 1 diabetes mellitus remains time-consuming in the clinical setting. We aimed to examine the diagnostic performance of a portable point-of-care diagnostic tool (POCD) for assessing sural nerve conduction during the screening of CAN.

METHODS

Nerve amplitude (AMPPOCD ) and conduction velocity (CVPOCD ) were measured in a cross-sectional study including 198 asymptomatic patients with type 1 diabetes. CAN was diagnosed by the Ewing score and power spectral heart rate [low-frequency (LF) and high-frequency (HF) activity]. Diagnostic accuracy was determined by ROC curves.

RESULTS

CVPOCD and AMPPOCD showed positive correlations with LF and HF, and a negative correlation with age. Overall, AMPPOCD had an 81.7% accuracy in identifying CAN [AUC = 0.817 (95% CI 0.692-0.942)] with an AMPPOCD  ≤6 μV showing 90% sensitivity and 73% specificity. In a stepwise binary logistic regression analysis, the model (R2 : 0.297; P < 0.001) retained the duration of type 1 diabetes [β: 1.131 (95% CI: 1.051-1.216); P = 0.001) and A1c [β: 2.131 (95% CI: 1.060-4.283); P = 0.034) as significant predictors of CAN. The combination of AMPPOCD  ≤6 μV + a type 1 diabetes duration of ≥8 years maximized the sensitivity, showing a diagnostic performance of 87% [AUC = 0.867 (95% CI 0.769-0.965)] with 90%, 76%, and 99%, sensitivity, specificity, and NPV, respectively. Adding A1c  ≥ 7% to this model maintained accuracy [AUC = 0.867 (95% CI: 0.788-0.963) and NPV (99%), while increasing specificity to 84%.

CONCLUSIONS

The combination of AMPPOCD with A1c and the duration of type 1 diabetes mellitus showed a good performance for the detection of asymptomatic CAN, making POCD an easy and rapid test for its routine screening in the clinical setting.

Diabetes Distal Peripheral Neuropathy: Subtypes and Diagnostic and Screening Technologies

Diabetes distal symmetrical peripheral neuropathy (DSPN) is the most prevalent form of neuropathy in industrialized countries, substantially increasing risk for morbidity and pre-mature mortality. DSPN may manifest with small-fiber disease, large-fiber disease, or a combination of both. This review summarizes: (1) DSPN subtypes (small- and large-fiber disease) with attention to clinical signs and patient symptoms; and (2) technological diagnosis and screening for large- and small-fiber disease with inclusion of a comprehensive literature review of published studies from 2015-present (N = 66). Review findings, informed by the most up-to-date research, advance critical understanding of DSPN large- and small-fiber screening technologies, including those designed for point-of-care use in primary care and endocrinology practices.

Diagnostic value of optic disc retinal nerve fiber layer thickness for diabetic peripheral neuropathy

OBJECTIVE

To investigate the value of optic disc retinal nerve fiber layer (RNFL) thickness in the diagnosis of diabetic peripheral neuropathy (DPN).

METHODS

Ninety patients with type 2 diabetes, including 60 patients without DPN (NDPN group) and 30 patients with DPN (DPN group), and 30 healthy participants (normal group) were enrolled. Optical coherence tomography (OCT) was used to measure the four quadrants and the overall average RNFL thickness of the optic disc. The receiver operator characteristic curve was drawn and the area under the curve (AUC) was calculated to evaluate the diagnostic value of RNFL thickness in the optic disc area for DPN.

RESULTS

The RNFL thickness of the DPN group was thinner than those of the normal and NDPN groups in the overall average ((101.07± 12.40) µm vs. (111.07±6.99) µm and (109.25±6.90) µm), superior quadrant ((123.00±19.04) µm vs. (138.93±14.16) µm and (134.47±14.34) µm), and inferior quadrant ((129.37±17.50) µm vs. (143.60±12.22) µm and (144.48±14.10) µm), and the differences were statistically significant. The diagnostic efficiencies of the overall average, superior quadrant, and inferior quadrant RNFL thicknesses, and a combined index of superior and inferior quadrant RNFL thicknesses were similar, and the AUCs were 0.739 (95% confidence interval (CI) 0.635-0.826), 0.683 (95% CI 0.576-0.778), 0.755 (95% CI 0.652-0.840), and 0.773 (95% CI 0.672-0.854), respectively. The diagnostic sensitivity of RNFL thickness in the superior quadrant reached 93.33%.

CONCLUSIONS

The thickness of the RNFL in the optic disc can be used as a diagnostic method for DPN.

Early Detection of Diabetic Peripheral Neuropathy: A Focus on Small Nerve Fibres

Diabetic peripheral neuropathy (DPN) is the most common complication of both type 1 and 2 diabetes. As a result, neuropathic pain, diabetic foot ulcers and lower-limb amputations impact drastically on quality of life, contributing to the individual, societal, financial and healthcare burden of diabetes. DPN is diagnosed at a late, often pre-ulcerative stage due to a lack of early systematic screening and the endorsement of monofilament testing which identifies advanced neuropathy only. Compared to the success of the diabetic eye and kidney screening programmes there is clearly an unmet need for an objective reliable biomarker for the detection of early DPN. This article critically appraises research and clinical methods for the diagnosis or screening of early DPN. In brief, functional measures are subjective and are difficult to implement due to technical complexity. Moreover, skin biopsy is invasive, expensive and lacks diagnostic laboratory capacity. Indeed, point-of-care nerve conduction tests are convenient and easy to implement however questions are raised regarding their suitability for use in screening due to the lack of small nerve fibre evaluation. Corneal confocal microscopy (CCM) is a rapid, non-invasive, and reproducible technique to quantify small nerve fibre damage and repair which can be conducted alongside retinopathy screening. CCM identifies early sub-clinical DPN, predicts the development and allows staging of DPN severity. Automated quantification of CCM with AI has enabled enhanced unbiased quantification of small nerve fibres and potentially early diagnosis of DPN. Improved screening tools will prevent and reduce the burden of foot ulceration and amputations with the primary aim of reducing the prevalence of this common microvascular complication.

Clinical Tools for Peripheral Neuropathy to Exclude Cardiovascular Autonomic Neuropathy in Type 2 Diabetes Mellitus

INTRODUCTION

Assessment for cardiovascular autonomic neuropathy (CAN) remains difficult in everyday clinical practice. We sought to examine the diagnostic utility of various simple tools for diabetic peripheral neuropathy (DPN) in the detection of CAN in type 2 diabetes mellitus.

METHODS

We examined 153 type 2 diabetes mellitus subjects by various DPN tools (vibration perception threshold, 10 g Semmes-Weinstein monofilament, Ipswich touch test, NC-stat^®/DPNCheck, neuropathy disability score) for the detection of CAN. CAN was diagnosed by the standardised cardiovascular autonomic reflex function tests.

RESULTS

For the diagnosis of CAN, assessment of small nerve fibre function (pinprick sensation, temperature perception) yielded a very high negative predictive value (97%), with high sensitivity (89%) and moderate specificity (73%). The vibration perception threshold was second in diagnostic utility (91% negative predictive value, 62% sensitivity and 75% specificity).

CONCLUSIONS

Based on their high negative predictive value, simple tools for DPN may prove useful to exclude CAN in type 2 diabetes mellitus. These encouraging results merit further evaluation to enable wider screening for CAN.

New Perspective in Diabetic Neuropathy: From the Periphery to the Brain, a Call for Early Detection, and Precision Medicine

Diabetic peripheral neuropathy (DPN) is a common chronic complication of diabetes mellitus. It leads to distressing and expensive clinical sequelae such as foot ulceration, leg amputation, and neuropathic pain (painful-DPN). Unfortunately, DPN is often diagnosed late when irreversible nerve injury has occurred and its first presentation may be with a diabetic foot ulcer. Several novel diagnostic techniques are available which may supplement clinical assessment and aid the early detection of DPN. Moreover, treatments for DPN and painful-DPN are limited. Only tight glucose control in type 1 diabetes has robust evidence in reducing the risk of developing DPN. However, neither glucose control nor pathogenetic treatments are effective in painful-DPN and symptomatic treatments are often inadequate. It has recently been hypothesized that using various patient characteristics it may be possible to stratify individuals and assign them targeted therapies to produce better pain relief. We review the diagnostic techniques which may aid the early detection of DPN in the clinical and research environment, and recent advances in precision medicine techniques for the treatment of painful-DPN.

The Diagnostic Utility of VibraTip for Distal Symmetrical Polyneuropathy in Type 2 Diabetes Mellitus

INTRODUCTION

The aim of this study was to assess the performance of VibraTip, a device used to test a person's vibration perception during routine checks for peripheral neuropathy, against two thresholds of the Neuropathy Disability Score (NDS) for diagnosing distal symmetrical polyneuropathy (DSPN) in patients with type 2 diabetes mellitus (T2DM).

METHODS

One hundred consecutive subjects with T2DM were enrolled in the study, of whom 54 were men. The mean age was 62.3 years, and the mean T2DM duration was 12.6 years. VibraTip was used at one foot site (on the pulp of the hallux; protocol A) and at three foot sites (pulp of the hallux and first and third metatarsal head; protocol B). NDS thresholds of  ≥ 3 and ≥ 6 were used to establish the diagnosis of DSPN.

RESULTS

Against the NDS ≥ 3 threshold, VibraTip showed a very high sensitivity (91.3%) and negative predictive value (NPV) (92%) and a high specificity (85.2%) with protocol A, and a very high sensitivity (95.6%) and NPV (96.1%) and a very high specificity (90.7%) with protocol B. Against the NDS ≥ 6 threshold, VibraTip showed a very high sensitivity (100%) and NPV (100%) and a very high specificity (95.2%) with protocol A, and very high sensitivity (100%) and NPV (100%) and very high specificity (96.8%) with protocol B.

CONCLUSIONS

The diagnostic performance of VibraTip is very high in patients with T2DM, rendering it a very useful device as a screening tool, particularly for the exclusion of DSPN. VibraTip performs very well at both NDS thresholds, but particularly well at the NDS ≥ 6 threshold. There appears to be no need to examine sites other than the hallux site with Vibratip.

Diabetic peripheral neuropathy: advances in diagnosis and strategies for screening and early intervention

Diabetic peripheral neuropathy (DPN) is a common complication of both type 1 and 2 diabetes. It is a leading cause of lower-limb amputation and disabling neuropathic pain. Amputations in patients with diabetes have a devastating effect on quality of life and are associated with an alarmingly low life expectancy (on average only 2 years from the amputation). Amputation also places a substantial financial burden on health-care systems and society in general. With the introduction of national diabetes eye screening programmes, the prevalence of blindness in working-age adults is falling. This is not the case, however, with diabetes related amputations. In this Review, we appraise innovative point-of-care devices that enable the early diagnosis of DPN and assess the evidence for early risk factor-based management strategies to reduce the incidence and slow the progression of DPN. We also propose a framework for screening and early multifactorial interventions as the best prospect for preventing or halting DPN and its devastating sequelae.

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

AIMS

To determine the relationships of sudomotor functions, nerve conductions and self-reported depressive symptoms in Chinese type 2 diabetes (T2DM) patients.

METHODS

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).

RESULTS

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).

CONCLUSION

Self-reported depressive symptoms might be associated with sudomotor dysfunction in Chinese T2DM patients.

Correlation of cardiac autonomic neuropathy with small and large peripheral nerve function in type 2 diabetes mellitus

AIMS

To analyse the correlation of cardiac autonomic neuropathy (CAN), sympathetic and parasympathetic dysfunction with the different diagnostic tools for large and small peripheral nerve fibres in type 2 diabetes mellitus (T2DM).

METHODS

We included 153 T2DM subjects (92 men) with mean age of 64.4 years. CAN, as well as sympathetic and parasympathetic dysfunction were diagnosed by the Ewing's cardiovascular reflex tests. Vibration perception threshold (VPT), monofilament, Ipswich Touch test, automated sural nerve conduction study and neuropathy disability score (NDS) evaluated large and small peripheral nerve fibre function.

RESULTS

CAN (adjusted odds ratio [aOR]: 44.57), parasympathetic (aOR: 18.40) and sympathetic dysfunction (aOR: 5.50) correlated with measures of small fibre function evaluated by pinprick sensation and temperature perception. Among tools for large nerve fibres, positive correlation was shown between: (1) CAN and abnormal VPT (aOR: 16.78), (2) parasympathetic dysfunction and abnormal VPT (aOR: 39.47).

CONCLUSIONS

CAN and parasympathetic dysfunction correlate with peripheral neuropathy, especially when the latter is assessed through VPT and measures of small fibre function as evaluated by pinprick sensation and temperature perception. The latter additionally correlate with sympathetic nervous system impairment.

Validity and reliability of a point-of-care nerve conduction device in diabetes patients

AIMS/INTRODUCTION

Although nerve conduction study (NCS) using a standard electromyography system (EMGS) is considered to be the gold standard in evaluating diabetic polyneuropathy, this examination requires expensive equipment and well-trained technicians. We aimed to validate a point-of-care device, NC-stat/DPNCheck™, that has been developed for widespread use of NCS in diabetic polyneuropathy.

MATERIALS AND METHODS

Diabetes patients underwent two kinds of NCS: DPNCheck™ and electromyography system. Inter-/intrarater reliability of DPNCheck™ were also determined by the intraclass correlation coefficient.

RESULTS

A total of 57 patients were evaluated. The parameters of NCS between the two methods correlated well (r = 0.7734 for the sural nerve conduction velocity, r = 0.6155 for the amplitude of sural nerve action potential). The intraclass correlation coefficients were excellent (intrarater: the velocity 0.767, the amplitude 0.811; interrater: the velocity 0.974, the amplitude 0.834).

CONCLUSIONS

The point-of-care device has excellent reproducibility and good agreement with standard electromyography system. The device might be useful to evaluate diabetic polyneuropathy.

Type of Diabetes Mellitus Has Influence on Electrophysiological Parameters

INTRODUCTION

Compulsory electromyoneurography (EMNG) analysis of all neurophysiological parameters, including the most sensitive parameter for early detection of diabetic polyneuropathy (cutaneous silent periods), in patients without subjective symptoms, and EMNG analysis demonstrates the existence of incipient signs for polynomial neuropathy due to which timely therapeutic approach is needed to prevent complications of diabetic disease and prevent irreversible changes in peripheral nerves.

AIM

Examine the influence of type diabetes mellitus, therapeutic modality, and gender of patients on neurophysiological parameters obtained by EMNG analysis.

METHODS

The study included 90 patients with diabetes who were divided into three groups of 30, depending on the duration of the disease. Group 1 consisted of 30 respondents with type 2 diabetes mellitus and up to 5 years of disease duration. Group 2 consisted of 30 respondents with type 2 diabetes mellitus type and 5 to 10 years of disease duration. Group 3 consisted of 30 respondents with Type 1 diabetes mellitus. An electron-neurography analysis of peripheral nerve in the extremities was performed.

RESULTS

Group 1 (50%) and group 2 (56.17%) respondents had statistically higher incidence of tingling than those in Group 3 (13.3%), p=0.004. Tingling was not statistically significantly different in relation to the examined groups (p=0.314). Reflexes were statistically the most preserved in Group 3 (86.7%), p = 0.001. Measurement of motor conductivity values at median nerve had a significant difference in all parameters (distal latency, amplitude, mean conduction velocity (MCV) and latency in the group with DM type 1, compared to respondents with DM type 2. The same significant difference between all parameters was found when testing peroneus nerve. When measuring motor velocity conductivity in ulnar nerve, there was no significant difference in amplitude, while DM1 type 1 patients had significant differences in values: distal latency and MCV p<0.0001, latency p<0.002. Measurement of sensory velocity was not statistically significant between patients with DM types 1 and 2. In relation to therapy, oral insulin therapy was not shown to be of statistical significance, except for tibialis amplitude measurements, where insulin-treated DM patients had a value amplitude of 12.96±1.48, and in oral therapy group less than 0.04 (p<0.05) 9.14±0.93. In the DM type 2 group no, neurophysiological parameters showed significant gender differences, while in respondents with DM type 2, where the disease lasted shorter, a significant gender difference was present in terms of motor velocity and sensory conductivity in all the nerves examines, except MCV in ulnar nerve. In the DM type 1 respondents, a significant gender difference was present in measuring MCV at tibial nerve and peroneus nerve (p <0.01 and p <0.02), as well as latency of MCV in H reflexes (p<0.01), in males was 56.25±1.03 and in females 32.89±0.47.

CONCLUSION

Diabetic polyneuropathy is significantly more present in patients older than 60 years who have type 2 diabetes mellitus (2/3 of those with a duration of 5 years or less and in ½ respondents with DM duration of less than 5 years), without any hesitation on the type of therapy. Measurement values of motor conductivity at median nerve had a significant difference in all parameters (distal latency, amplitude, MCV, and latency F) in the group with DM type 1. The same significant difference between all parameters was also found in n. peroneus. Distal latency values at sural nerve and tibial nerve, latency values and MCV in H reflexes, do not depend on DM type.

One-stop microvascular screening service: an effective model for the early detection of diabetic peripheral neuropathy and the high-risk foot

AIMS

To evaluate the feasibility of a one-stop microvascular screening service for the early diagnosis of diabetic distal symmetrical polyneuropathy, painful distal symmetrical polyneuropathy and the at-risk diabetic foot.

METHODS

People with diabetes attending retinal screening in hospital and community settings had their feet examined by a podiatrist. Assessment included: Toronto Clinical Neuropathy Score evaluation; a 10-g monofilament test; and two validated, objective and quick measures of neuropathy obtained using the point-of-care devices 'DPN-Check', a hand-held device that measures sural nerve conduction velocity and amplitude, and 'Sudoscan', a device that measures sudomotor function. The diagnostic utility of these devices was assessed against the Toronto Clinical Neuropathy Score as the 'gold standard'.

RESULTS

A total of 236 consecutive people attending the retinal screening service, 18.9% of whom had never previously had their feet examined, were evaluated. The prevalence of distal symmetrical polyneuropathy, assessed using the Toronto Clinical Neuropathy Score, was 30.9%, and was underestimated by 10-g monofilament test (14.4%). The prevalence of distal symmetrical polyneuropathy using DPN-check was 51.5% (84.3% sensitivity, 68.3% specificity), 38.2% using Sudoscan foot electrochemical skin conductance (77.4% sensitivity, 68.3% specificity), and 61.9% using abnormality in either of the results (93.2% sensitivity, 52.8% specificity). The results of both devices correlated with Toronto Clinical Neuropathy Score (P<0.001). A new diagnosis of painful distal symmetrical polyneuropathy was made in 59 participants (25%), and 56.6% had moderate- or high-risk foot. Participants rated the service very highly.

CONCLUSIONS

Combined, eye, foot and renal screening is feasible, has a high uptake, reduces clinic visits, and identifies painful distal symmetrical polyneuropathy and the at-risk foot. Combined large- and small-nerve-fibre assessment using non-invasive, quantitative and quick point-of-care devices may be an effective model for the early diagnosis of distal symmetrical polyneuropathy.

Cardio-Ankle Vascular Index and Indices of Diabetic Polyneuropathy in Patients with Type 2 Diabetes

The cardio-ankle vascular index (CAVI) is used to test vascular function and is an arterial stiffness marker and potential predictor of cardiovascular events. This study aimed to analyze the relation between objective indices of diabetic polyneuropathy (DPN) and the CAVI. One hundred sixty-six patients with type 2 diabetes mellitus were included in this study. We used nerve conduction studies (NCSs) and the coefficient of variation of the R-R interval to evaluate DPN. We estimated arteriosclerosis by the CAVI. Simple and multiple linear regression analyses were performed between neuropathy indices and the CAVI. In univariate analysis, the CAVI showed significant associations with sural sensory nerve conduction velocity and median F-wave conduction velocity. Multiple linear regression analysis for the CAVI showed that sural nerve conduction velocity and median F-wave conduction velocity were significant explanatory variables second only to age. In multiple linear regression analysis for sural nerve conduction velocity among neuropathy indices, the CAVI remained the most significant explanatory variable. In multiple linear regression analysis for median nerve F-wave conduction velocity among neuropathy indices, the CAVI remained the second most significant explanatory variable following HbA1c. These results suggest a close relationship between macroangiopathy and DPN.

Diabetic Neuropathy Evaluated by a Novel Device: Sural Nerve Conduction Is Associated with Glycemic Control and Ankle-Brachial Pressure Index in Japanese Patients with Diabetes

BACKGROUND

Currently, no international diagnostic criteria for diabetic neuropathy (DN) have been established. Recently, a novel point-of-care sural nerve conduction device has been developed. We aimed to investigate associations between DN and clinical parameters related to the development and progression of DN by using this novel device.

METHODS

We conducted a retrospective observational study in patients with diabetes whose sural nerve functions were measured using DPN Check between January 2015 and October 2016. Multiple and logistic regression analyses were conducted to assess the associations of sural nerve conduction velocity (SNCV) and amplitude (SNAP) with clinical parameters related to DN.

RESULTS

A total of 740 patients were enrolled in this study. At baseline, 211 patients were diagnosed with DN by using DPN Check. The sensitivity, specificity, and positive likelihood ratio of DPN Check compared with ankle reflex as reference were 81%, 46%, and 1.5, respectively. Of these, 182 patients were followed up for approximately 1 year to measure changes in SNCV and SNAP. Both SNCV and SNAP were inversely associated with duration of diabetes, plasma glucose levels, and hemoglobin A1c levels at baseline, whereas these were positively associated with ankle-brachial index. Logistic regression analysis revealed that poor glycemic control was associated with increased risk of reduction in both SNCV [odds ratio = 1.570; 95% confidence interval (CI) = 1.298-1.898; p < 0.001] and SNAP (odds ratio = 1.408; 95% CI = 1.143-1.735; p = 0.001), and longer duration of diabetes was also significantly associated with an increased risk of reduction in both SNCV (odds ratio = 1.058; 95% CI = 1.032-1.084; p < 0.001) and SNAP (odds ratio = 1.049; 95% CI = 1.019-1.079; p = 0.001).

CONCLUSION

Sural nerve functions were significantly associated with glycemic control and arteriosclerosis in patients with diabetes. DPN Check may be useful as a screening tool to identify DN in clinical practice.