NerveCheck for the Detection of Sensory Loss and Neuropathic Pain in Diabetes

The co-existence of peripheral and vestibular neuropathy in diabetes: a cross-sectional study

PURPOSE

Diabetic neuropathy can lead to decreased peripheral sensation and motor neuron dysfunction associated with impaired postural control and risk of falling. However, the relationship between decreased peripheral sensation and impaired vestibular function in diabetes mellitus is poorly investigated. Therefore, the aim of this study was to investigate the relationship between peripheral and autonomic measurements of diabetic neuropathy and measurements of vestibular function.

METHODS

A total of 114 participants with type 1 diabetes (n = 52), type 2 diabetes (n = 51) and controls (n = 11) were included. Vestibular function was evaluated by video head impulse testing. Peripheral neuropathy was assessed by quantitative sensory testing and nerve conduction. Autonomic neuropathy using the COMPASS 31 questionnaire. Data were analyzed according to data type and distribution.

RESULTS

Measurements of vestibular function did not differ between participants with type 1 diabetes, type 2 diabetes or controls (all p-values above 0.05). Subgrouping of participants according to the involvement of large-, small- or autonomic nerves did not change this outcome. Correlation analyses showed a significant difference between COMPASS 31 and right lateral gain value (ρ = 0.23, p = 0.02,), while no other significant correlations were found.

CONCLUSION

Diabetic neuropathy does not appear to impair vestibular function in diabetes, by means of the VOR.

CLINICAL TRIALS

NCT05389566, May 25th, 2022.

Association of HbA1c Variability with Vibrating Perception Threshold in Middle-Aged and Elderly Patients with Type 2 Diabetes Mellitus: A Retrospective Cohort Study

Purpose

To investigate the relationship between HbA1c variability and vibrating perception threshold (VPT) in middle-aged and elderly patients with type 2 diabetes mellitus (T2DM).

Patients and Methods

A total of 367 middle-aged and elderly patients with T2DM were enrolled. All patients were categorized into the control and vibration sensation deficiency group (VSD) based on VPT. Clinical data were collected. The coefficient of variation of glycated hemoglobin A1c (HbA1c-CV) and the mean glycated hemoglobin A1c(HbA1c-Mean) are considered as indexes of HbA1c variability. Multivariate logistic regression analysis, the generalized linear model and ROC curve correlation analysis were used to analyze the correlation of various factors and VPT.

Results

The multivariate logistic regression analysis revealed that age, systolic blood pressure (SBP), and HbA1c-CV were identified as risk factors for vibration sensation deficiency in middle-aged and elderly patients with T2DM, while estimated glomerular filtration rate (eGFR), triiodothyronine (T3), and alanine aminotransferase (ALT) were considered as protective factors. In the unadjusted generalized linear model, a significant association was observed between HbA1c-CV and VPT values. After adjusting for age, diabetic duration, SBP, homeostatic model assessment for beta-cell function (HOMA-β), ALT, eGFR, T3, 24-hour urinary protein excretion levels, and HbA1c-Mean, HbA1c-CV remained significantly correlated with VPT values on both sides. (left side, B=2.560, 95% CI 1.298~3.823; P<0.001; right side, B=2.608, 95% CI 1.498~3.718, P<0.001). The area under the curve (AUC) for HbA1c-CV and VSD prevalence was 0.723, with a sensitivity of 79.85%, specificity of 56.22%.

Conclusion

The risk of developing VSD increases proportionally with higher HbA1c-CV levels in middle-aged and elderly patients with T2DM. Reaching and maintaining blood glucose stability is essential to the mitigation of diabetes peripheral neuropathy occurrence.

Quantitative sensory testing defines the trajectory of sensory neuropathy after severe COVID-19

AIMS

To assess sensory neuropathy development after severe COVID-19.

METHODS

Patients with severe COVID-19 underwent assessment of neuropathic symptoms, tendon reflexes, and quantitative sensory testing to evaluate vibration (VPT), cold (CPT), warm (WPT) and heat perception thresholds (HPT) within 1-3 weeks of admission and after 1-year.

RESULTS

32 participants with severe COVID-19 aged 68.6 ± 12.4 (18.8 % diabetes) were assessed. At baseline, numbness and neuropathic pain were present in 56.3 % and 43.8 % of participants, respectively. On the feet, VPT, WPT, and HPT were abnormal in 81.3 %, CPT was abnormal in 50.0 % and HPT on the face was abnormal in 12.5 % of patients. At 1-year follow-up, the prevalence of abnormal VPT (81.3 % vs 50.0 %, P < 0.01), WPT (81.3 % vs 43.8 %, P < 0.01), and HPT (81.3 % vs 50.0 %, P < 0.01) decreased, with no change in CPT (P = 0.21) on the feet or HPT on the face (P = 1.0). Only participants without diabetes recovered from an abnormal VPT, CPT, and WPT. Patients with long-COVID (37.5 %) had comparable baseline VPT, WPT and CPT with those without long-COVID (P = 0.07-0.69).

CONCLUSIONS

Severe COVID-19 is associated with abnormal vibration and thermal thresholds which are sustained for up to 1 year in patients with diabetes. Abnormal sensory thresholds have no association with long-COVID development.

Peripheral Neuropathy in Diabetes Mellitus: Pathogenetic Mechanisms and Diagnostic Options

Diabetic neuropathy (DN) is one of the main microvascular complications of both type 1 and type 2 diabetes mellitus. Sometimes, this could already be present at the time of diagnosis for type 2 diabetes mellitus (T2DM), while it appears in subjects with type 1 diabetes mellitus (T1DM) almost 10 years after the onset of the disease. The impairment can involve both somatic fibers of the peripheral nervous system, with sensory-motor manifestations, as well as the autonomic system, with neurovegetative multiorgan manifestations through an impairment of sympathetic/parasympathetic conduction. It seems that, both indirectly and directly, the hyperglycemic state and oxygen delivery reduction through the vasa nervorum can determine inflammatory damage, which in turn is responsible for the alteration of the activity of the nerves. The symptoms and signs are therefore various, although symmetrical painful somatic neuropathy at the level of the lower limbs seems the most frequent manifestation. The pathophysiological aspects underlying the onset and progression of DN are not entirely clear. The purpose of this review is to shed light on the most recent discoveries in the pathophysiological and diagnostic fields concerning this complex and frequent complication of diabetes mellitus.

The Role of Neuropathy Screening Tools in Patients Affected by Fibromyalgia

Fibromyalgia syndrome (sFM) is one of the most common causes of chronic pain. This study aimed to assess the presence of small and large fiber impairment in fibromyalgic patients by applying validated scores used in the screening for diabetic neuropathy. The endpoints for the study were the assessment of neuropathy prevalence in sFM patients using the NerveCheck Master (NCM), the Michigan Neuropathy Screening Instrument (MNSI), the Diabetic Neuropathy Symptom (DNS) and the Douleur Neuropathique 4 Questions (DN4). The sample was composed of 46 subjects: subjects with sFM (n = 23) and healthy controls (HC) (n = 23). The positivity rates in each group for DN4 were significantly different (p < 0.001), with a prevalence in symptomatic subjects of 56.3% (n = 9) among sFM individuals. A similar difference was also observed with the DNS total score (p < 0.001). NCM and MNSI did not disclose significant differences between the two groups. This finding seems to confirm the data regarding the prevalence of a neuropathic pain in sFM patients.

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.

Corneal confocal microscopy for the diagnosis of diabetic peripheral neuropathy: A systematic review and meta-analysis

INTRODUCTION

Corneal confocal microscopy (CCM) is a rapid non-invasive ophthalmic imaging technique that identifies corneal nerve fiber damage. Small studies suggest that CCM could be used to assess patients with diabetic peripheral neuropathy (DPN).

AIM

To undertake a systematic review and meta-analysis assessing the diagnostic utility of CCM for sub-clinical DPN (DPN- ) and established DPN (DPN+ ).

DATA SOURCES

Databases (PubMed, Embase, Central, ProQuest) were searched for studies using CCM in patients with diabetes up to April 2020.

STUDY SELECTION

Studies were included if they reported on at least one CCM parameter in patients with diabetes.

DATA EXTRACTION

Corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL), and inferior whorl length (IWL) were compared between patients with diabetes with and without DPN and controls. Meta-analysis was undertaken using RevMan V.5.3.

DATA SYNTHESIS

Thirty-eight studies including ~4,000 participants were included in this meta-analysis. There were significant reductions in CNFD, CNBD, CNFL, and IWL in DPN- vs controls (P < 0.00001), DPN+ vs controls (P < 0.00001), and DPN+ vs DPN- (P < 0.00001).

CONCLUSION

This systematic review and meta-analysis shows that CCM detects small nerve fiber loss in subclinical and clinical DPN and concludes that CCM has good diagnostic utility in DPN.

Widespread sensory neuropathy in diabetic patients hospitalized with severe COVID-19 infection

AIMS

To characterize the distribution and severity of sensory neuropathy using a portable quantitative sensory testing (QST) device in diabetic patients (DM) hospitalized with severe COVID-19 infection.

METHODS

Four patients with diabetes and severe SARS-CoV-2 requiring non-invasive ventilation for a protracted duration underwent clinical, laboratory and radiologic assessment and detailed evaluation of neuropathic symptoms, neurological assessment, QST on the dorsum of the foot and face using NerveCheck Master with assessment of taste and smell.

RESULTS

All four subjects developed neuropathic symptoms characterized by numbness in the feet with preserved reflexes. QST confirmed symmetrical abnormality of vibration and thermal thresholds in both lower limbs in all patients and an abnormal heat pain threshold on the face of two patients and altered taste and smell.

CONCLUSIONS

Severe COVID-19 infection with hypoxemia is associated with neuropathic symptoms and widespread sensory dysfunction in patients with DM.

TIR generated by continuous glucose monitoring is associated with peripheral nerve function in type 2 diabetes

AIMS

Continuous glucose monitoring (CGM)-derived time-in-range (TIR) of 3.9-10 mmol/L is associated with diabetic retinopathy in type 2 diabetes (T2DM), but its relationship to peripheral nerve function has not been previously investigated. To explore the association between the TIR and nerve conduction study parameters in patients with T2DM, we performed a cross-sectional analysis.

METHODS

A total of 740 patients with T2DM were enrolled in this study. All of the participants were divided into tertiles according to the TIR (TIR low: ≤53%; TIR medium: 54-76%; TIR high: ≥77%). Composite Z-scores of nerve conduction velocity (CV), latency, and amplitude were calculated. The linear correlation between the TIR and composite nerve function Z-score was evaluated and risk assessment was analysed using binary logistic regression.

RESULTS

The composite Z-score of the CV and amplitude increased with higher TIR and the composite Z-score of latency significantly decreased as the TIR tertiles increased (all P trend < 0.05). After adjusting for age, diabetes duration, height, weight and other confounding factors, higher TIR was associated with a higher composite Z-score of CV (β = 0.230, P < 0.001), amplitude (β = 0.099, P = 0.010), and lower composite Z-score of latency (β = -0.172, P < 0.001). The risk of TIR tertiles and low composite Z-score of CV remained significant even after adjustment of HbA1c (TIR medium: OR = 0.48, P = 0.001; TIR high: OR = 0.41, P < 0.001).

CONCLUSIONS

Higher TIR tertiles were independently associated with better peripheral nerve function. CGM-derived TIR may be a promising approach to screen patients for further assessment of possible diabetic peripheral neuropathy.

Instruments of Choice for Assessment and Monitoring Diabetic Foot: A Systematic Review

Diabetic foot is the most frequent disorder among the chronic complications of diabetes, happening in 25% of patients. Objective clinical outcome measures are tests or clinical instruments that provide objective values for result measurement. The aim of this study was to carry out a systematic review of specific objective clinical outcome measures focused on the assessment and monitoring of diabetic foot disorders. The databases used were PubMed, CINAHL, Scopus, PEDro, Cochrane, SciELO and EMBASE. Search terms used were foot, ankle, diabet*, diabetic foot, assessment, tools, instruments, objective outcome measures, valid*, reliab*. Because of the current published evidence, diabetic neuropathy assessment via sudomotor analysis, cardiovascular autonomic neuropathy and peripheral vascular disease detection by non-invasive electronic devices, wound 3D dimensional measurement, hyperspectral imaging for ulcer prediction and the probe-to-bone test for osteomyelitis diagnosis were highlighted in this study.

Association between thermal threshold abnormalities and peripheral artery disease in patients with type 2 diabetes

Both diabetic peripheral neuropathy and peripheral arterial disease (PAD) cause foot ulcers and often result in non-traumatic amputations in patients with type 2 diabetes. This study aimed to evaluate the association between clinical variables, PAD, and subclinical diabetic small fiber peripheral neuropathy detected by abnormal thermal thresholds of the lower extremities in patients with type 2 diabetes.We investigated 725 consecutive patients with type 2 diabetes (male/female: 372/353; mean age, 67 ± 11 years) who did not have apparent cardiovascular disease (including coronary artery disease, arrhythmia, and stroke) and who underwent the quantitative sensory test for thermal (warm and cold) thresholds of the lower limbs and ankle-brachial index (ABI)/toe-brachial index (TBI) examinations in 2015. The analyses included glycated hemoglobin, estimated glomerular filtration rate, and other characteristics.In total, 539 (74.3%) patients showed an abnormality of at least 1 thermal threshold in their feet. All patients with an abnormal ABI (<0.9) had concurrent impaired thermal thresholds, and 93% (87/94) of patients with an abnormal TBI experienced abnormal thermal thresholds in the lower limbs. Age- and sex-adjusted TBI and estimated glomerular filtration rate were significantly correlated to abnormal thermal thresholds. In the multivariate analysis, fasting plasma glucose, and glycated hemoglobin were independently associated with abnormal thermal thresholds in the lower extremities.Subclinical thermal threshold abnormalities of the feet are significantly associated with PAD and nephropathy in patients who have type 2 diabetes without cardiovascular disease.