How should peripheral neuropathy be assessed in people with diabetes in primary care? A population-based comparison of four measures

New Horizons in Diabetic Neuropathies: An Updated Review on their Pathology, Diagnosis, Mechanism, Screening Techniques, Pharmacological, and Future Approaches

BACKGROUND

One of the largest problems for global public health is diabetes mellitus (DM) and its micro and macrovascular consequences. Although prevention, diagnosis, and treatment have generally improved, its incidence is predicted to keep rising over the coming years. Due to the intricacy of the molecular mechanisms, which include inflammation, oxidative stress, and angiogenesis, among others, discovering treatments to stop or slow the course of diabetic complications is still a current unmet need.

METHODS

The pathogenesis and development of diabetic neuropathies may be explained by a wide variety of molecular pathways, hexosamine pathways, such as MAPK pathway, PARP pathway, oxidative stress pathway polyol (sorbitol) pathway, cyclooxygenase pathway, and lipoxygenase pathway. Although diabetic neuropathies can be treated symptomatically, there are limited options for treating the underlying cause.

RESULT

Various pathways and screening models involved in diabetic neuropathies are discussed, along with their possible outcomes. Moreover, both medicinal and non-medical approaches to therapy are also explored.

CONCLUSION

This study highlights the probable involvement of several processes and pathways in the establishment of diabetic neuropathies and presents in-depth knowledge of new therapeutic approaches intended to stop, delay, or reverse different types of diabetic complications.

[Diabetic neuropathy and diabetic foot syndrome (update 2023)]

These are the guidelines for diagnosis and treatment of diabetic neuropathy and diabetic foot.The position statement summarizes characteristic clinical symptoms and techniques for diagnostic assessment of diabetic neuropathy, including the complex situation of the diabetic foot syndrome. Recommendations for the therapeutic management of diabetic neuropathy, especially for the control of pain in sensorimotor neuropathy, are provided. The needs to prevent and treat diabetic foot syndrome are summarized.

Distal Symmetric and Cardiovascular Autonomic Neuropathies in Brazilian Individuals with Type 2 Diabetes Followed in a Primary Health Care Unit: A Cross-Sectional Study

The paucity of epidemiological data regarding diabetes complications in Brazil motivated us to evaluate the prevalence rates of distal symmetric polyneuropathy (DSP) and of cardiovascular autonomic neuropathy (CAN) in individuals with type 2 diabetes (T2D) followed in a primary care unit. A total of 551 individuals (59.3% women, 65 years old; diabetes duration of 10 years; HbA1c of 7.2%, medians) were included in this cross-sectional study. DSP was diagnosed by sum of the Neuropathy Symptoms Score (NSS) and Modified Neuropathy Disability Score (NDS) and by the Semmes-Weinstein monofilament. CAN was diagnosed by cardiovascular autonomic reflex tests combined with spectral analysis of heart rate variability. The prevalence rates of DSP were 6.3% and 14.3%, as evaluated by the sum of NSS and NDS and by the Semmes-Weinstein monofilament, respectively. Those with DSP diagnosed by monofilament presented longer diabetes duration, worse glycemic control and a higher stature. The prevalence rates of incipient and definitive CAN were 12.5% and 10%, respectively. Individuals with definitive CAN presented a higher frequency of hypercholesterolemia and of arterial hypertension. The higher prevalence rate of DSP with the use of the monofilament suggests that it may be a more appropriate tool to diagnose DSP in the primary care setting in Brazil.

Challenges of neuropathic pain: focus on diabetic neuropathy

Neuropathic pain is a frequent condition caused by a lesion or disease of the central or peripheral somatosensory nervous system. A frequent cause of peripheral neuropathic pain is diabetic neuropathy. Its complex pathophysiology is not yet fully elucidated, which contributes to underassessment and undertreatment. A mechanism-based treatment of painful diabetic neuropathy is challenging but phenotype-based stratification might be a way to develop individualized therapeutic concepts. Our goal is to review current knowledge of the pathophysiology of peripheral neuropathic pain, particularly painful diabetic neuropathy. We discuss state-of-the-art clinical assessment, validity of diagnostic and screening tools, and recommendations for the management of diabetic neuropathic pain including approaches towards personalized pain management. We also propose a research agenda for translational research including patient stratification for clinical trials and improved preclinical models in relation to current knowledge of underlying mechanisms.

Clinical Response to Real-Time Patient-Reported Diabetic Peripheral Neuropathy Symptoms

INTRODUCTION

To assess clinician response to real-time patient-reported data about diabetic peripheral neuropathy (DPN) symptoms, we analyzed DPN diagnosis and treatment patterns after administration of a 4-question symptom questionnaire in a large vertically integrated health care system.

METHODS

Retrospective cohort study to analyze data from 160,852 patients screened for DPN symptoms from April 2012 to March 2014. Electronic medical record data were used to study changes in DPN diagnosis, treatment initiation, and treatment intensification. We used logistic regression to study the association of patient characteristics with the odds of clinical response.

RESULTS

Of patients queried, 50,684 (31.5%) reported symptoms. Patients reporting DPN symptoms experienced a greater increase in new DPN diagnoses (16 percentage points; p < 0.0001) and medication use (4 percentage points; p < 0.0001) compared with those denying symptoms. Among patients reporting symptoms, women and nonwhite patients were less likely to receive a DPN diagnosis, whereas older patients were more likely to receive a DPN diagnosis. Overall, patients who were older, were Asian (hazard ratio = 0.67, 95% confidence interval = 0.63-0.77), and had lower socioeconomic status (hazard ratio = 0.89, 95% confidence interval = 0.80-0.99) were less likely to be treated. However, these racial and socioeconomic differences were not statistically significant for patients with preexisting DPN diagnoses.

CONCLUSION

Patients' real-time reports of DPN symptoms were associated with increased clinical activity. Patient- and clinician-level factors associated with the likelihood of receiving a DPN diagnosis need further study because a formal diagnosis may be associated with more equitable treatment.

Evaluation of the risk of diabetic peripheral neuropathy: Design and validation of the NeuDiaCan nursing screening procedure

OBJECTIVE

To design and validate a nursing screening procedure for diabetic peripheral neuropathy in primary care.

METHODS

The study was carried out in three phases. 1)Construction of an item bank to form the procedure with an exit score describing the patient's clinical situation. 2)Test and reduction of the initial tentative procedure on a sample of 50 patients using community nurse consultations, eliminating the components with low inter-intra nurse reliability. 3)Validation of the version of the procedure obtained in the previous step on a sample of 106 patients. Calculation of validity and reliability by eliminating components with low criterion validity with respect to the results of the diagnostic electromyography used as a reference standard. Cut-off points were estimated for the use of the procedure as a screening tool, predictive values, performance, internal consistency and inter-nurse reliability.

RESULTS

The initial tentative procedure consisted of 12 components that were reduced to 10. In the process of validation of this second version the procedure was simplified again, eventually comprising 6 components, with a cut-off point of 2.5 in its output scale, the point at which it reaches adequate values of sensitivity and negative predictors to be used as a screening instrument. For this cut-off point the inter-intra nurse reliability, criterion validity and predictive validity reached acceptable values.

CONCLUSIONS

NeuDiaCan as a nursing screening procedure for diabetic peripheral neuropathy in primary care is valid, reliable and easy to use.

[Diabetic neuropathy and diabetic foot syndrome (Update 2019)]

These are the guidelines for diagnosis and treatment of diabetic neuropathy and diabetic foot. Diabetic neuropathy comprises a number of mono- and polyneuropathies, plexopathies, radiculopathies and autonomic neuropathy.The position statement summarizes characteristic clinical symptoms and techniques for diagnostic assessment of diabetic neuropathy, including the complex situation of the diabetic foot syndrome. Recommendations for the therapeutic management of diabetic neuropathy, especially for the control of pain in sensorimotor neuropathy, are provided. The needs to prevent and treat diabetic foot syndrome are summarized.

Correlation Between Different Stages of Diabetic Nephropathy and Neuropathy in Patients with T2DM: A Cross-Sectional Controlled Study

INTRODUCTION

Early detection of diabetic peripheral neuropathy (DPN) is critical in patients with type 2 diabetes mellitus (T2DM) due to the lack of targeted therapy for DPN. We have investigated the relationship between different stages of diabetic nephropathy and DPN in an attempt to elucidate whether albuminuria can be used as an early warning signal of DPN progression.

METHODS

A total of 217 T2DM patients who met the inclusion criteria were recruited from the Department of Endocrinology, Nanfang Hospital between January 2016 and June 2016. These patients were placed in groups based on urinary albumin excretion rate (UAER) and estimated glomerular filtration rate. Nerve conduction studies, the Semmes-Weinstein monofilament test (SWMT) and the vibration perception threshold (VPT) test were conducted. Multiple linear regression analysis, multivariate logistic regression and receiver-operating characteristic (ROC) analysis were performed to investigate the relationship between different stages of diabetic nephropathy and DPN in these patients.

RESULTS

Significant differences were observed in the conduction velocity (CV) and amplitude of sensory/motor nerve potential among the T2DM patients at different stages of diabetic nephropathy (all p  < 0.05). The UAER and duration of diabetes were found to be independent factors associated with the mean CV and amplitude of sensory/motor nerve potential (all p  < 0.05). A disease duration of > 10 years (p  = 0.025) and a higher total cholesterol value (p  = 0.024) were found to be significantly associated with abnormal SWMT results. A UAER of > 300 mg/24 h (p  = 0.007) and a diastolic blood pressure of > 100 mmHg (p  = 0.042) were associated with a higher risk for abnormal VPT. A UAER  of > 300 mg/24 h (p  < 0.001) and a disease duration of > 10 years (p  = 0.02) were observed to be significantly correlated with DPN. The ROC analysis showed that the optimal cutoff values of UAER and duration as indicators of DPN were 90.5 mg/24 h and 9.5 years, respectively (both p  < 0.001).

CONCLUSIONS

The results suggest that diabetic nephropathy is closely associated with the development of DPN in T2DM patients and that UAER and disease duration can be used as warning indicators of DPN progression.

CHINESE CLINICAL TRIALS REGISTER NUMBER

ChiCTR-ROC-16007701.

Overcoming barriers to diabetic polyneuropathy management in primary care

Diabetic polyneuropathy is a highly prevalent and costly complication of diabetes that is frequently underdiagnosed and undertreated in primary care settings. In this article, we discuss challenges in the management of diabetic polyneuropathy symptoms, including diagnostic complexity, the limited efficacy and high side effect rates associated with available treatments and the time constrained primary care visit. We call for the development of novel patient-centric, system-level strategies that engage patients between physician visits in order to facilitate timely communication of symptoms and treatment response and to promote patient-centered care.

Fuzzy expert system for diagnosing diabetic neuropathy

AIM

To design a fuzzy expert system to help detect and diagnose the severity of diabetic neuropathy.

METHODS

The research was completed in 2014 and consisted of two main phases. In the first phase, the diagnostic parameters were determined based on the literature review and by investigating specialists’ perspectives (n = 8). In the second phase, 244 medical records related to the patients who were visited in an endocrinology and metabolism research centre during the first six months of 2014 and were primarily diagnosed with diabetic neuropathy, were used to test the sensitivity, specificity, and accuracy of the fuzzy expert system.

RESULTS

The final diagnostic parameters included the duration of diabetes, the score of a symptom examination based on the Michigan questionnaire, the score of a sign examination based on the Michigan questionnaire, the glycolysis haemoglobin level, fasting blood sugar, blood creatinine, and albuminuria. The output variable was the severity of diabetic neuropathy which was shown as a number between zero and 10, had been divided into four categories: absence of the disease, (the degree of severity) mild, moderate, and severe. The interface of the system was designed by ASP.Net (Active Server Pages Network Enabled Technology) and the system function was tested in terms of sensitivity (true positive rate) (89%), specificity (true negative rate) (98%), and accuracy (a proportion of true results, both positive and negative) (93%).

CONCLUSION

The system designed in this study can help specialists and general practitioners to diagnose the disease more quickly to improve the quality of care for patients.

Diagnostic Accuracy of Monofilament Tests for Detecting Diabetic Peripheral Neuropathy: A Systematic Review and Meta-Analysis

OBJECTIVE

To systematically evaluate the diagnostic accuracy of monofilament tests for detecting diabetic peripheral neuropathy.

METHODS

We searched EMBASE (OvidSP), MEDLINE (OvidSP), the Cochrane Library, and Web of Science to identify diagnostic accuracy trials of monofilament tests for detecting diabetic peripheral neuropathy. We used a hierarchical summary receiver operating characteristics (HSROC) model to conduct the meta-analysis of diagnostic accuracy of monofilament tests for detecting diabetic peripheral neuropathy.

RESULTS

A total of 19 comparative trials met the inclusion criteria and were part of the qualitative synthesis. Eight trials using nerve conduction studies as the reference standard were selected for the meta-analysis. The pooled sensitivity and specificity of monofilament tests for detecting diabetic peripheral neuropathy were 0.53 (95% confidence interval (CI) 0.32 to 0.74) and 0.88 (95% CI 0.78 to 0.94), respectively. The pooled positive likelihood ratio and negative likelihood ratio were 4.56 (95% CI 2.93 to 7.10) and 0.53 (95% CI 0.35 to 0.81), respectively.

CONCLUSIONS

Our review indicated that monofilament tests had limited sensitivity for screening diabetic peripheral neuropathy. The clinical use of the monofilament test in the evaluation of diabetic peripheral neuropathy cannot be encouraged based on currently available evidence.

A randomised trial of the effect and cost-effectiveness of early intensive multifactorial therapy on 5-year cardiovascular outcomes in individuals with screen-detected type 2 diabetes: the Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen-Detected Diabetes in Primary Care (ADDITION-Europe) study

BACKGROUND

Intensive treatment (IT) of cardiovascular risk factors can halve mortality among people with established type 2 diabetes but the effects of treatment earlier in the disease trajectory are uncertain.

OBJECTIVE

To quantify the cost-effectiveness of intensive multifactorial treatment of screen-detected diabetes.

DESIGN

Pragmatic, multicentre, cluster-randomised, parallel-group trial.

SETTING

Three hundred and forty-three general practices in Denmark, the Netherlands, and Cambridge and Leicester, UK.

PARTICIPANTS

Individuals aged 40-69 years with screen-detected diabetes.

INTERVENTIONS

Screening plus routine care (RC) according to national guidelines or IT comprising screening and promotion of target-driven intensive management (medication and promotion of healthy lifestyles) of hyperglycaemia, blood pressure and cholesterol.

MAIN OUTCOME MEASURES

The primary end point was a composite of first cardiovascular event (cardiovascular mortality/morbidity, revascularisation and non-traumatic amputation) during a mean [standard deviation (SD)] follow-up of 5.3 (1.6) years. Secondary end points were (1) all-cause mortality; (2) microvascular outcomes (kidney function, retinopathy and peripheral neuropathy); and (3) patient-reported outcomes (health status, well-being, quality of life, treatment satisfaction). Economic analyses estimated mean costs (UK 2009/10 prices) and quality-adjusted life-years from an NHS perspective. We extrapolated data to 30 years using the UK Prospective Diabetes Study outcomes model [version 1.3; (©) Isis Innovation Ltd 2010; see www.dtu.ox.ac.uk/outcomesmodel (accessed 27 January 2016)].

RESULTS

We included 3055 (RC, n = 1377; IT, n = 1678) of the 3057 recruited patients [mean (SD) age 60.3 (6.9) years] in intention-to-treat analyses. Prescription of glucose-lowering, antihypertensive and lipid-lowering medication increased in both groups, more so in the IT group than in the RC group. There were clinically important improvements in cardiovascular risk factors in both study groups. Modest but statistically significant differences between groups in reduction in glycated haemoglobin (HbA1c) levels, blood pressure and cholesterol favoured the IT group. The incidence of first cardiovascular event [IT 7.2%, 13.5 per 1000 person-years; RC 8.5%, 15.9 per 1000 person-years; hazard ratio 0.83, 95% confidence interval (CI) 0.65 to 1.05] and all-cause mortality (IT 6.2%, 11.6 per 1000 person-years; RC 6.7%, 12.5 per 1000 person-years; hazard ratio 0.91, 95% CI 0.69 to 1.21) did not differ between groups. At 5 years, albuminuria was present in 22.7% and 24.4% of participants in the IT and RC groups, respectively [odds ratio (OR) 0.87, 95% CI 0.72 to 1.07), retinopathy in 10.2% and 12.1%, respectively (OR 0.84, 95% CI 0.64 to 1.10), and neuropathy in 4.9% and 5.9% (OR 0.95, 95% CI 0.68 to 1.34), respectively. The estimated glomerular filtration rate increased between baseline and follow-up in both groups (IT 4.31 ml/minute; RC 6.44 ml/minute). Health status, well-being, diabetes-specific quality of life and treatment satisfaction did not differ between the groups. The intervention cost £981 per patient and was not cost-effective at costs ≥ £631 per patient.

CONCLUSIONS

Compared with RC, IT was associated with modest increases in prescribed treatment, reduced levels of risk factors and non-significant reductions in cardiovascular events, microvascular complications and death over 5 years. IT did not adversely affect patient-reported outcomes. IT was not cost-effective but might be if delivered at a reduced cost. The lower than expected event rate, heterogeneity of intervention delivery between centres and improvements in general practice diabetes care limited the achievable differences in treatment between groups. Further follow-up to assess the legacy effects of early IT is warranted.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00237549.

FUNDING DETAILS

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 64. See the NIHR Journals Library website for further project information.

The Need for Improved Management of Painful Diabetic Neuropathy in Primary Care

The provision of care for patients with type II diabetes in primary care must involve assessing patients for peripheral neuropathy of the feet. Objectives. This paper will demonstrate that painful diabetic neuropathy (PDN) is poorly assessed for and treated in primary care. Methods. A critical analysis of research will be conducted to identify the prevalence and impact of PDN among individuals with type II diabetes. Results. Research evidence and best practice guidelines are widely available in supporting primary care practitioners to better assess for and treat PDN. However, the lack of knowledge, awareness, and implementation of such research and guidelines prevents patients with PDN from receiving appropriate care. Discussion. Much international research exists on the prevalence and impact of PDN in primary care; however, Canadian research is lacking. Furthermore, the quantity and quality of research on treatment modalities for PDN are inadequate. Finally, current research and guidelines on PDN management are inadequately implemented in the clinical setting. Conclusion. The undertreatment of PDN has significant implications on the individual, family, and society. Healthcare practitioners must be more aware of and better implement current research and guidelines into practice to resolve this clinical issue.

Effect of early multifactorial therapy compared with routine care on microvascular outcomes at 5 years in people with screen-detected diabetes: a randomized controlled trial: the ADDITION-Europe Study

OBJECTIVE

To determine the benefit of multifactorial treatment on microvascular complications among people with type 2 diabetes detected by screening.

RESEARCH DESIGN AND METHODS

This study was a multicenter cluster randomized controlled trial in primary care with randomization at the practice level. In four centers in Denmark; Cambridge, U.K.; the Netherlands; and Leicester, U.K., 343 general practices participated in the trial. Eligible for follow-up were 2,861 of the 3,057 people with diabetes detected by screening included in the original trial. Biomedical data on nephropathy were collected in 2,710 (94.7%) participants, retinal photos in 2,190 (76.6%), and questionnaire data on peripheral neuropathy in 2,312 (80.9%). The prespecified microvascular end points were analyzed by intention to treat. Results from the four centers were pooled using fixed-effects meta-analysis.

RESULTS

Five years after diagnosis, any kind of albuminuria was present in 22.7% of participants in the intensive treatment (IT) group and in 24.4% in the routine care (RC) group (odds ratio 0.87 [95% CI 0.72-1.07]). Retinopathy was present in 10.2% of the IT group and 12.1% of the RC group (0.84 [0.64-1.10]), and severe retinopathy was present in one patient in the IT group and seven in the RC group. Neuropathy was present in 4.9% and 5.9% (0.95 [0.68-1.34]), respectively. Estimated glomerular filtration rate increased between baseline and follow-up in both groups (4.31 and 6.44 mL/min, respectively).

CONCLUSIONS

Compared with RC, an intervention to promote target-driven, intensive management of patients with type 2 diabetes detected by screening was not associated with significant reductions in the frequency of microvascular events at 5 years.

Evaluation of clinical tools and their diagnostic use in distal symmetric polyneuropathy

AIMS

To compare the diagnostic usefulness of tuning fork, monofilament, biothesiometer and skin biopsies in peripheral neuropathy in individuals with varying glucose metabolism.

METHODS

Normoglycaemic, impaired glucose tolerance (IGT) and type 2 diabetes (T2DM) individuals were recruited. Nerve conduction studies (NCS) and thermal threshold tests were performed. Vibrotactile sense was tested with a biothesiometer and a 128-Hz tuning fork. Touch/pressure perception was examined with a 10-g monofilament. Skin biopsies were performed and intraepidermal nerve fibres were quantified. Distal symmetric polyneuropathy (DSPN) was defined as neuropathy disability score ≥2 and abnormal NCS. Thermal threshold tests were used to define small nerve fibre neuropathy (sDSPN) in cases where NCS (large nerve fibres) were normal.

RESULTS

The prevalence of DSPN and sDSPN in the whole group (n=119) was 18% and 23%, respectively. For the biothesiometer, a cut-off of ≥24.5V had a sensitivity of 82% and specificity of 70% (AUC=0.81, 95% CI 0.71-0.91) when evaluating DSPN. An intraepidermal nerve fibre density cut-off of ≤3.39fibres/mm showed a sensitivity of 74% and specificity of 70% in the detection of sDSPN, whereas the sensitivity of the tuning fork and the biothesiometer were relatively low, 46% and 67%, respectively. When combining skin biopsies with the tuning fork, 10 more sDSPN cases were identified. Adding skin biopsy to the combination of the tuning fork and biothesiometer increased the sensitivity of finding sDSPN cases, but not DSPN, from 81% to 93%.

CONCLUSION

Using a biothesiometer in clinical routine might be a sensitive method to detect large nerve fibre dysfunction in the lower extremity, whereas skin biopsies in combination with methods measuring vibrotactile sense could increase the diagnostic sensitivity of detecting peripheral neuropathy at an early stage.

Comparison of the accuracy of monofilament testing at various points of feet in peripheral diabetic neuropathy screening

BACKGROUND

Diabetic Peripheral Neuropathy is one of the most prevalent complications of diabetes mellitus. The development and progression of such complications are responsible for much of the morbidity and mortality. The purpose of this study was to evaluate the effectiveness of Semmes-Weinstein monofilament ten gram in 3, 4, eight and ten points in the screening of diabetic peripheral neuropathy in patients with diabetes mellitus.

METHODS

In a descriptive correlational design, 150 patients with diabetes mellitus were selected using convenience sampling. All patients were evaluated for sensory neuropathy using ten gram Semmes-Weinstein Monofilaments and questionnaire on neuropathy symptoms. In the next phase, nerve conduction velocity was examined. The most common subjective symptoms were paresthesia of both feet, pain in feet, burning sensation in the extremities and numbness in the extremities.

RESULTS

The results showed that the sensitivity of Monofilament in three and four points were 35.9 to 53.8 present and 38.5 to 51.3 percent respectively. Specificity of Monofilament the same points, were 73.9 to 84.7 and 73 to 87.4 percent respectively. Monofilament sensitivity at eight and ten points were 38.5 to 61.5 and 64.1 to 30.8 percent respectively. Also, specificity of the same points were 77.5 to 95.5 and 64 to 89.2 percent respectively. It was revealed that the difference sensitivity and specificity of Monofilament in three and four points with sensitivity and specificity in eight and ten point is not statistically significant.

CONCLUSIONS

This study showed that Semmes-Weinstein monofilament can easily use as a simple and inexpensive device for screening. Since increasing the number of points it was not significantly difference. Therefore, we suggest that screening for diabetic peripheral neuropathy, especially in large populations to avoid wasting time on Monofilament application, areas like three or four points eight and ten points could be used.

[Diabetic neuropathy]

These are the guidelines for diagnosis and treatment of diabetic neuropathy. This diabetic late complication comprises a number of mono- and polyneuropathies, plexopathies, radiculopathies and autonomic neuropathy. The position statement summarizes characteristic clinical symptoms and techniques for diagnostic assessment of diabetic neuropathy. Recommendations for the therapeutic management of diabetic neuropathy, especially for the control of pain in sensomotoric neuropathy, are provided.

A method for corneal nerves automatic segmentation and morphometric analysis

The segmentation and morphometric analysis of corneal sub-basal nerves, from corneal confocal microscopy images, has gained recently an increased interest. This interest arises from the possibility of using changes in these nerves as the basis of a simple and non-invasive method for early detection and follow-up of peripheral diabetic neuropathy, a major cause of chronic disability in diabetic patients. Here, we propose one method for automatic segmentation and analysis of corneal nerves from images obtained in vivo through corneal confocal microscopy. The method is capable of segmenting corneal nerves, with sensitivity near 90% and a percentage of false recognitions with an average of 5.3%. The nerves tortuosity was calculated and shows statistically significant differences between healthy controls and diabetic individuals, in accordance to what is reported in the literature.

Deteriorating tactile sensation in patients with hand syndromes associated with diabetes: a two-year observational study

AIMS

To observe the natural history of hand function during a two-year period in participants with hand syndromes associated with diabetes and to determine factors related to changing function.

METHODS

Hand function was measured over three annual visits using Disability of the Arm, Shoulder and Hand (DASH) and SF-36v2 questionnaires, grip strength, light touch and 9-hole peg tests. Light touch was tested with WEST monofilaments at 7 sites on the hand (score 35 to 0). Data were analyzed using repeated-measures ANOVA, Spearman's correlation, and Wilcoxon signed-rank tests.

RESULTS

Participants (n=60) were aged 61 ± 10.5 years, 57% female, diagnosed with diabetes and at least one of four associated hand disorders. Presentations of carpal tunnel syndrome, or past release (n=27, 45%) and trigger finger (n=24, 40%) were common. Tactile sensation was reduced during the two-year period (median, range; 30 months, 25-40 months). Initial median (inter-quartile range) scores for the dominant hand of 25.5 (22-28.5) were reduced to 23 (21.5-27). This sensory loss was weakly associated with HbA1c (r=0.30, p=0.05) and occurred predominantly in participants with trigger finger (p=0.05).

CONCLUSIONS

Light touch perception was reduced in longstanding diabetic hand syndromes. Tactile abnormalities that were detected by clinical examination progressed during a two year period and were related to metabolic control and musculoskeletal diagnosis.

How much does screening bring forward the diagnosis of type 2 diabetes and reduce complications? Twelve year follow-up of the Ely cohort

AIMS

There are continuing uncertainties about how much screening for type 2 diabetes brings forward the clinical diagnosis and the impact that earlier diagnosis has on health outcomes. We compared the duration of diabetes and health outcomes in a population invited for diabetes screening at 5-yearly intervals from 1990 (screened population) with those in a similar population not invited for screening (unscreened population).

METHODS

This was a parallel-group, cohort study of people aged 40-65 years, free of known diabetes, identified from the population register of a general practice in Ely, Cambridgeshire, UK (n = 4,936). In 1990-1992, one-third (n = 1,705), selected randomly, received an invitation for screening for diabetes and cardiovascular risk factors at 5-yearly intervals (screened population). From the remainder of the sampling frame, 1,705 randomly selected individuals were invited to diabetes screening 10 years later (unscreened population). Patients with diabetes from both populations were invited for a health assessment, including biochemical, anthropometric and questionnaire measures, and testing for the presence of diabetic complications

RESULTS

Of the 199 eligible individuals with diabetes diagnosed during follow-up, 152 (76%) attended for health assessment. The median duration of clinically recognised diabetes was significantly longer in cases arising in the screened (5.0 years) compared with the unscreened population (1.7 years; p = 0.006). Clinical measures, prescribed medication and functional status were similar between screened and unscreened populations.

CONCLUSIONS

Diabetes screening resulted in cases being identified on average 3.3 years earlier, a difference significantly shorter than previous estimates. Earlier diagnosis did not appear to impact on health outcomes. Further evidence is needed to justify the introduction of population-based screening.

Comparison of shoe-length fit between people with and without diabetic peripheral neuropathy: a case-control study

Background

Amongst the many identified mechanisms leading to diabetic foot ulceration, ill-fitting footwear is one. There is anecdotal evidence that people with diabetic peripheral neuropathy wear shoes that are too small in order to increase the sensation of fit. The aim of this study was to determine whether people with diabetic sensory neuropathy wear appropriate length footwear.

Methods

A case–control design was used to compare internal shoe length and foot length differences between a group of people with diabetes and peripheral sensory neuropathy and a group of people without diabetes and no peripheral sensory neuropathy. Shoe and foot length measurements were taken using a calibrated Internal Shoe Size Gauge® and a Brannock Device®, respectively.

Results

Data was collected from 85 participants with diabetes and 118 participants without diabetes. The mean difference between shoe and foot length was not significantly different between the two groups. However, a significant number of participants within both groups had a shoe to foot length difference that lay outside a previously suggested 10 to 15 mm range. From the diabetic and non-diabetic groups 82% (70/85) and 66% (78/118), respectively had a foot to shoe length difference outside this same range.

Conclusions

This study shows that although there is no significant difference in shoe-length fit between participants with and without neuropathy, a significant proportion of these populations wear shoes that are either too long or too short for their foot length according to the 10 to 15 mm value used for comparison. The study has highlighted the need for standardised approaches when considering the allowance required between foot and internal shoe length and for the measurement and comparison of foot and shoe dimensions.

A novel robotic monofilament test for diabetic neuropathy

OBJECTIVE

The use of the Semmes-Weinstein (SW) monofilament test is recommended as a screening method for diabetic neuropathy. It offers an important chance to prevent further complications of diabetic foot. We aimed to develop a prototype Robotic Monofilament Inspector that can be used as a standard machine for screening of diabetic neuropathy.

METHODS

Development was divided into three parts: computer software, control box, and Robotic Monofilament Inspector. The examiner conducted the SW test (by hand and by robotic inspector), vibration perception threshold, and Toronto Clinical Scoring System without knowledge of patient information. The unpaired t test or Wilcoxon rank-sum test was used to determine the differences between independent groups in terms of continuous outcomes, while the χ(2) test was used to determine categorical outcomes. Agreement between the various diabetic neuropathy tests was measured using the kappa statistic.

RESULTS

The SW test and vibration perception threshold were more valid tests for neuropathy than the Toronto test. The robotic test was in excellent agreement with the two former tests and appeared to be valid (kappa statistic, 0.35-0.81). Another indirect evidence for the validity of the robotic test was the finding that diabetic patients with foot ulcers had a higher prevalence of neuropathy (77%vs. 38%). This might indicate that the robotic test was more valid than the manual test.

CONCLUSION

The Robotic Monofilament Inspector could be used as a simple screening machine. This prototype may be developed further for routine clinical use.

Mechanosensitivity during lower extremity neurodynamic testing is diminished in individuals with Type 2 Diabetes Mellitus and peripheral neuropathy: a cross sectional study

Background

Type 2 Diabetes Mellitus (T2DM) and diabetic symmetrical polyneuropathy (DSP) impact multiple modalities of sensation including light touch, temperature, position sense and vibration perception. No study to date has examined the mechanosensitivity of peripheral nerves during limb movement in this population. The objective was to determine the unique effects T2DM and DSP have on nerve mechanosensitivity in the lower extremity.

Methods

This cross-sectional study included 43 people with T2DM. Straight leg raise neurodynamic tests were performed with ankle plantar flexion (PF/SLR) and dorsiflexion (DF/SLR). Hip flexion range of motion (ROM), lower extremity muscle activity and symptom profile, intensity and location were measured at rest, first onset of symptoms (P1) and maximally tolerated symptoms (P2).

Results

The addition of ankle dorsiflexion during SLR testing reduced the hip flexion ROM by 4.3° ± 6.5° at P1 and by 5.4° ± 4.9° at P2. Individuals in the T2DM group with signs of severe DSP (n = 9) had no difference in hip flexion ROM between PF/SLR and DF/SLR at P1 (1.4° ± 4.2°; paired t-test p = 0.34) or P2 (0.9° ± 2.5°; paired t-test p = 0.31). Movement induced muscle activity was absent during SLR with the exception of the tibialis anterior during DF/SLR testing. Increases in symptom intensity during SLR testing were similar for both PF/SLR and DF/SLR. The addition of ankle dorsiflexion induced more frequent posterior leg symptoms when taken to P2.

Conclusions

Consistent with previous recommendations in the literature, P1 is an appropriate test end point for SLR neurodynamic testing in people with T2DM. However, our findings suggest that people with T2DM and severe DSP have limited responses to SLR neurodynamic testing, and thus may be at risk for harm from nerve overstretch and the information gathered will be of limited clinical value.

Prediction of incident diabetic neuropathy using the monofilament examination: a 4-year prospective study

OBJECTIVE

To determine the specific monofilament examination score that predicts the subsequent 4-year incidence of diabetic neuropathy with the highest degree of diagnostic accuracy.

RESEARCH DESIGN AND METHODS

Longitudinal follow-up of 175 of 197 (89%) participants in the Toronto Diabetic Neuropathy Cohort without baseline neuropathy for incident neuropathy. We examined the baseline monofilament examination score (and other simple sensory screening tests) by receiver operating characteristic (ROC) curve analysis.

RESULTS

Incident diabetic neuropathy developed in 50 (29%) participants over a mean follow-up of 4.1 years (interquartile range 2.6-7.1 years). Although male sex, longer diabetes duration, taller height, and higher blood pressure at baseline were associated with incident neuropathy, the strongest association was with a lower baseline monofilament score (score out of 8 was 3.7 +/- 2.5 for incident neuropathy vs. 5.7 +/- 2.3 for those who did not develop neuropathy; P < 0.001). The optimal threshold score for risk of incident neuropathy was <or=5 sensate stimuli out of 8, with 72% sensitivity, 64% specificity, positive and negative likelihood ratios of 2.5 and 0.35, and positive and negative predictive values of 87 and 46%, respectively (chi(2) = 20.7, P < 0.001). Area under the ROC curve was significantly greater for the monofilament examination compared with that for other simple sensory tests.

CONCLUSIONS

A simple threshold of <or=5 sensate stimuli out of 8 discriminates 4-year risk of diabetic neuropathy with acceptable operating characteristics. Although there are limitations in its specificity for prediction of future neuropathy onset, the monofilament examination is appropriate as a simple diabetic neuropathy screening instrument generalizable to the clinical setting.

In vivo confocal microscopy of corneal small fiber damage in diabetes mellitus

BACKGROUND

Advanced diabetic keratopathy includes impaired corneal sensation, reduced tear secretion, conjunctival squamous metaplasia, and goblet cell loss, as well as susceptibility to corneal erosions and ulcerations. It is thought to be a form of generalized diabetic neuropathy. Early diagnosis of nerve fiber degeneration is essential to prevent further damage.

METHODS

We examined the corneal innervation pattern of patients with diabetes mellitus type 1 and 2 of various durations by in vivo confocal microscopy, and correlated our findings to the severity of diabetic retinopathy, corneal sensation, peripheral diabetic neuropathy in the lower limb, and nephropathy.

RESULTS

Nerve fiber length (NFL) was significantly different between patients without diabetic retinopathy and controls (p = 0.028). In patients with non-proliferative diabetic retinopathy (NPDR) and patients with proliferative diabetic retinopathy (PDR), nerve fiber parameters including density (NFD), NFL, and corneal nerve branching (NB) showed a difference with increasing significance compared to healthy persons. A history of nephropathy and/or peripheral neuropathy (all p < 0.001), decreased corneal sensation (all p < or = 0.03), and pathological vibration sensation (p < or = 0.04) were significantly associated with a decrease in NFD, NFL, and NB (except vibration sensation). Unexpectedly, diabetic patients with normal corneal and vibration sensation demonstrated significant changes in NFD (p = 0.005), NFL, and NB (both p = 0.001) compared to healthy volunteers with intact corneal and vibration sensation.

CONCLUSION

Confocal microscopy is a valuable tool for demonstrating subtle corneal nerve alterations in vivo. It is capable of demonstrating diabetic nerve fiber damage earlier than corneal sensation testing and vibration perception assessment in the lower limb.

Accuracy of monofilament testing to diagnose peripheral neuropathy: a systematic review

PURPOSE

We wanted to summarize evidence about the diagnostic accuracy of the 5.07/10-g monofilament test in peripheral neuropathy.

METHODS

We conducted a systematic review of studies in which the accuracy of the 5.07/10-g monofilament was evaluated to detect peripheral neuropathy of any cause using nerve conduction as reference standard. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool.

RESULTS

We reviewed 173 titles and abstracts of articles to identify 54 potentially eligible studies, of which 3 were finally selected for data synthesis. All studies were limited to patients with diabetes mellitus and showed limitations according to the QUADAS tool. Sensitivity ranged from 41% to 93% and specificity ranged from 68% to 100%. Because of the heterogenous nature of the studies, a meta-analysis could not be accomplished.

CONCLUSIONS

Despite the frequent use of monofilament testing, little can be said about the test accuracy for detecting neuropathy in feet without visible ulcers. Optimal test application and defining a threshold should have priority in evaluating monofilament testing, as this test is advocated in many clinical guidelines. Accordingly, we do not recommend the sole use of monofilament testing to diagnose peripheral neuropathy.

The Semmes Weinstein monofilament examination as a screening tool for diabetic peripheral neuropathy

OBJECTIVE

The purpose of this systematic review is to evaluate current evidence in the literature on the efficacy of Semmes Weinstein monofilament examination (SWME) in diagnosing diabetic peripheral neuropathy (DPN).

METHODS

The PubMed database was searched through August 2008 for articles pertaining to DPN and SWME with no language or publication date restrictions. Studies with original data comparing the diagnostic value of SWME with that of one or more other modalities for DPN in patients with diabetes mellitus were analyzed. Data were extracted by two independent investigators. Diagnostic values were calculated after classifying data by reference test, SWME methodology, and diagnostic threshold.

RESULTS

Of the 764 studies identified, 30 articles were selected, involving 8365 patients. There was great variation in both the reference test and the methodology of SWME. However, current literature suggests that nerve conduction study (NCS) is the gold standard for diagnosing DPN. Four studies were identified which directly compared SWME with NCS and encompassed 1065 patients with, and 52 patients without diabetes mellitus. SWME had a sensitivity ranging from 57% (95% confidence interval [CI], 44% to 68%) to 93% (95% CI, 77% to 99%), specificity ranging from 75% (95% CI, 64% to 84%) to 100% (95% CI, 63% to 100%), positive predictive value (PPV) ranging from 84% (95% CI, 74% to 90%) to 100% (95% CI, 87% to 100%), and negative predictive value (NPV) ranging from 36% (95% CI, 29% to 43%) to 94% (95% CI, 91% to 96%).

CONCLUSIONS

There is great variation in the current literature regarding the diagnostic value of SWME as a result of different methodologies. To maximize the diagnostic value of SWME, a three site test involving the plantar aspects of the great toe, the third metatarsal, and the fifth metatarsals should be used. Screening is vital in identifying DPN early, enabling earlier intervention and management to reduce the risk of ulceration and lower extremity amputation.

Vibration perception threshold and the law of mobility in diabetic mellitus patients

BACKGROUND

Diabetic neuropathy is a family of nerve disorders with progressive loss of nerve function in 15% of diabetes mellitus (DM) subjects. Vibration Perception Threshold (VPT) is one of the modalities of testing loss of protective sensation. Law of mobility for VPT is well known for normal subjects, but not for diabetic subjects. This is a pilot study to evaluate and plot the law of mobility for VPT among DM subjects.

METHODS

We used biothesiometer to find the VPT of several areas in upper and lower extremities for normal and diabetic subjects. VPT of normal and diabetic subjects for different foot areas from proximal to distal is evaluated for 30 subjects. All the subjects are screened for peripheral artery occlusive disease with ankle brachial pressure index (0.9 or above). VPT values of different areas are arranged in a proximal to distal order for the analysis.

RESULTS

VPT values monotonically decrease from proximal to distal areas. Vierodt's law of mobility holds well for normal subjects in both feet areas. The law of mobility does not hold good for the DM subjects in one or both feet areas.

CONCLUSIONS

The VPT value of diabetic subjects reveals that the law of mobility do not holds good for diabetic subjects in foot areas. Though the number of subjects is small, all the subjects defied the law.

Lower-extremity strength differences predict activity limitations in people with chronic stroke

BACKGROUND

Body system impairments following stroke have a complex relationship with functional activities. Although gait and balance deficits are well-documented in people after stroke, the overlapping influence of body impairments makes it difficult to prioritize interventions.

OBJECTIVE

This study examined the relationship between prospectively selected measures of body function and structure (body mass index, muscle strength, sensation, and cognition) and activity (gait speed, gait endurance, and functional balance) in people with chronic stroke.

DESIGN

This was a cross-sectional, observational study.

METHODS

Twenty-six individuals with mean (SD) age of 57.6 (11) years and time after stroke of 45.4 (43) months participated. Four variables (body mass index, muscle strength difference between the lower extremities, sensation difference between the lower extremities, and Mini-Mental Status Exam score) were entered into linear regression models for gait speed, Six-Minute Walk Test distance, and Berg Balance Scale score.

RESULTS

Lower-extremity strength difference was a significant individual predictor for gait speed, gait endurance, and functional balance. Cognition significantly predicted only gait speed.

LIMITATIONS

The authors did not include all possible factors in the model that may have influenced gait and balance in these individuals.

CONCLUSIONS

Strength deficits in the hemiparetic lower extremity should be an important target for clinical interventions to improve function in people with chronic stroke.

Hand disorders, hand function, and activities of daily living in elderly men with type 2 diabetes

AIMS/HYPOTHESIS

This study aimed to examine hand disorders, symptoms, overall hand function, activities of daily living (ADLs), and life satisfaction in elderly men with type 2 diabetes mellitus (DM), impaired glucose tolerance (IGT), and normal glucose tolerance (NGT).

METHODS

Subjects were interviewed and evaluated with a battery of clinical and laboratory tests, including hand assessment, and a questionnaire.

RESULTS

HbA1c differed between groups (highest in DM, especially in long-term DM). Limited joint motion (LJM), for example, prayer sign and Dupuytren's contracture, was most common in individuals with DM, followed by individuals with IGT, as compared to those with NGT. Vibrotactile sense was impaired symmetrically in the index and little fingers in DM. However, there were no differences for sensibility, dexterity, grip strength, and cold intolerance between groups. Individuals with long-term (>15 years) DM were more affected regarding sensibility and ADL than individuals with short-term DM, who had more sleep disturbances. ADL difficulties were less among IGT subjects. Vibrotactile sense showed correlations with Semmes-Weinstein monofilament test and static two-point discrimination.

CONCLUSIONS/INTERPRETATION

Dupuytren's contracture and impaired vibrotactile sense in finger pulps occurred in patients with DM but not in those with IGT, although LJM occurred in both IGT and DM patients. A longer duration of DM was associated with more severe neuropathy and ADL difficulties. Life satisfaction was high, and hand disorders did not have a significant impact on ADL.

Vibrotactile sense in median and ulnar nerve innervated fingers of men with Type 2 diabetes, normal or impaired glucose tolerance

AIMS

To investigate vibrotactile sense (large fibre neuropathy) at different frequencies in index and little fingers (median and ulnar nerves, respectively) of subjects with diabetes, or impaired (IGT) or normal glucose tolerance (NGT).

METHODS

Vibration thresholds (tactilometry at seven frequencies (8, 16, 32, 64, 125, 250 and 500 Hz)) and median nerve function (electrophysiology) were examined in men (age 73.4 +/- 0.12 years; n = 58, mean +/- sd) with persistent NGT (n = 28) or IGT (n = 7) or with Type 2 diabetes mellitus (T2DM) (n = 23) for > 15 years.

RESULTS

HbA1c was increased and vibrotactile sense (sensibility index) was impaired in index and little fingers in men with T2DM. Vibration thresholds were particularly increased at 16, 250 and 500 Hz in the little finger (ulnar nerve). T2DM subjects showed electrophysiological (gold standard) signs of neuropathy in the median nerve. Although subjects with persistent IGT had higher HbA1c, vibrotactile sensation and electrophysiology remained normal. HbA1c did not correlate with vibrotactile sense or electrophysiology, but the latter two correlated with respect to Z-score (sign of neuropathy) in forearm (NGT) and at wrist level (NGT and DM).

CONCLUSIONS

Vibration thresholds are increased in the finger pulps in T2DM subjects, particularly at specific frequencies in ulnar nerve innervated finger pulps. Neuropathy is not present in IGT. Tactilometry, with a multi-frequency approach, is a sensitive technique to screen for large fibre neuropathy in T2DM. Frequency-related changes may mirror dysfunction of various receptors.

Assessing subclinical tactual deficits in the hand function of diabetic blind persons at risk for peripheral neuropathy

OBJECTIVE

To assess subclinical impairments in tactual hand function produced by diabetes mellitus in late-blind adults with diabetic retinopathy.

DESIGN

The survey compares diabetic blind with nondiabetic blind and blindfolded sighted controls in terms of their performance on a battery of tests that assess tactual hand function.

SETTING

Subjects were evaluated at their rehabilitation program center in Madrid.

PARTICIPANTS

Nine (referred) diabetic blind subjects affected by diabetic retinopathy versus 10 (referred) nondiabetic blind subjects versus 10 blindfolded sighted volunteers, all right-handed and matched for age. Subjects were referred by the training professionals of the rehabilitation program center and asked to volunteer.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Cutaneous force and spatial resolution thresholds, haptic psychophysical functions for perceived roughness, weight, and size, and both accuracy and response times for haptic classification of 3-dimensional common objects. Measures of joint mobility, muscular strength, and motor dexterity were also included.

RESULTS

The diabetic blind performed significantly poorer than the controls in terms of force sensitivity (distal and proximal finger pads, and palm), spatial resolution (distal finger pad only), motor dexterity, perceived roughness, and finally, haptic object classification response times for texture-diagnostic objects.

CONCLUSIONS

Subclinical disturbances in the tactual hand function of the diabetic blind subjects were only documented in perceptual and motor tasks for which cutaneous, as opposed to kinesthetic, information was particularly relevant.

Advanced diagnostic methods of small fiber diabetic peripheral neuropathy

Early detection and diagnosis is most important in small fiber diabetic peripheral neuropathy (DPN) management. Traditionally used diagnostic methods could not detect different nerve fiber function and had low sensitivity and specificity and huge inter- and intra-individual variation and coefficient of variance. So we need more objective and sensitive and specific diagnostic tools. In this review, we will discuss about recently developed diagnostic methods of small fiber DPN.

Painful leg ulceration: a prospective, longitudinal cohort study

This study aimed to explore the relationship between pain mechanism, pain intensity, and leg ulcer characteristics using a 6-month longitudinal cohort study in a community setting in the north of England. Patients with leg ulceration referred consecutively to district nurses were invited to participate (n=96). The main outcome measures were pain intensity using daily visual analogue scores, leg ulcer characteristics (etiology, size, location, duration), and LANSS (Leeds Assessment of Neuropathic Symptoms and Signs). Results suggested that type, duration, position, and size of the leg ulcer had no effect on average daily pain scores. Using the LANSS questionnaire, 43.5% of respondents reported symptoms suggestive of a neuropathic mechanism to their pain. Patients with neuropathic symptoms had higher average daily pain scores (p<0.001). Fewer people had healed ulcers at 6 months with neuropathic symptoms compared with those with no neuropathic symptoms (30.8 vs. 52.1%). It would seem that the severity of pain can not be predicted by the type, size, position, or duration of ulceration. Patients who scored positively for neuropathic symptoms had higher average daily pain scores and fewer had healed leg ulcers at 6 months compared with those who did not experience neuropathic signs and symptoms.

Quantitative Sensory Findings in Patients With Bortezomib-Induced Pain

Bortezomib (PS-341) is a newly developed proteosome inhibitor that shows extremely promising antineoplastic effects against a variety of neoplasias. Neuropathic pain is emerging as a major complication of bortezomib. Although clinical reports have appeared in the literature describing the general symptoms of bortezomib chemoneuropathy, specific quantitative sensory data that detail the sensory deficits that might yield insight to the primary afferent dysfunction contributing to this pain is lacking. In this report, it is shown that patients with bortezomib-induced neuropathic pain have significantly elevated touch detection threshold and slotted peg board time, impaired sharpness detection, and elevated thresholds for the detection of skin warming and heat pain. Patients also had increased reports of cold pain. These data indicate that bortezomib-induced neuropathy is associated with deficits in Abeta, Adelta, and C caliber primary afferent fibers.

PERSPECTIVE

This work demonstrates that pain induced by the chemotherapy drug bortezomib is accompanied by dysfunction in all fiber types in sensory nerves. Impaired Abeta and C sensory function also extends into areas of skin that are not perceived as affected by pain.

Dysfunction in multiple primary afferent fiber subtypes revealed by quantitative sensory testing in patients with chronic vincristine-induced pain

Vincristine is one of the frontline chemotherapy drugs for the treatment of numerous lymphoid neoplasias. The main dose-limiting complication of vincristine is the development of painful peripheral neuropathy. Although clinical reports have appeared in the literature detailing the symptoms of vincristine neuropathy, quantitative sensory testing data that might yield insight to dysfunction in subsets of primary afferents are lacking. In this report, pain descriptors and anatomical distributions of sensory abnormalities were collected in each patient. Touch detection threshold, sharpness detection threshold, the thresholds for the detection of skin warming, heat pain, skin cooling, and the perception of cooling-induced pain were measured in patients with chronic vincristine-induced pain in each area of sensory abnormality and in skin perceived as outside the affected areas. Elevated touch detection thresholds were observed both within and outside areas affected by pain and sensory abnormality. Elevated sharpness and warm detection thresholds were noted only in areas affected by pain. These data suggest that chronic vincristine-induced pain is associated with dysfunction in Abeta, Adelta, and C caliber primary afferent fibers. Deficits in Abeta fibers appear to precede and presage deficits in the other fiber types, whereas deficits in Adelta- and C-fiber function appear to be specifically associated with the generation of pain.

Corneal Diabetic Neuropathy: A Confocal Microscopy Study

PURPOSE

To evaluate the role of corneal confocal microscopy in the diagnosis of morphologic damage of the corneal sub-basal nerve plexus in diabetic patients and to correlate corneal confocal microscopy findings with peripheral diabetic neuropathy.

METHODS

Corneal sub-basal nerve plexus parameters were quantified by corneal confocal microscopy in 42 diabetic patients and 27 age-matched controls. The parameters quantified were the number of fibers, the tortuosity of fibers, the number of beadings, and the branching pattern of the fibers. Peripheral neuropathy was also quantified using the Michigan Neuropathy Screening Instrument.

RESULTS

The number of fibers, number of beadings, and branching pattern of fibers significantly decreases in diabetic patients versus control subjects (P<.0001; P<.0001; P=.0006, respectively), whereas nerve tortuosity significantly increases (P<.0001). The same corneal sub-basal nerve plexus parameters show a statistical trend, suggesting progression of corneal neuropathy with peripheral diabetic neuropathy.

CONCLUSIONS

Corneal confocal microscopy represents a new tool in the diagnosis, clinical evaluation, and follow-up of peripheral diabetic neuropathy. This study found that diabetes damages corneal nerves, particularly the corneal sub-basal nerve plexus. This damage may be easily and accurately documented using corneal confocal microscopy.

Comparison of different screening tests for detecting diabetic foot neuropathy

INTRODUCTION

Regarding the major role of sensory neuropathy in diabetic foot ulcers, the use of an appropriate screening test for early detection of this neuropathy has a crucial role in the management of diabetic foot disorders. As there were no previous studies that performed all screening tests in the same group of patients, we performed all tests in a single group of diabetic patients and compared them to find out the possible differences between the results.

METHODS

A total of 142 diabetic outpatients at Shariati Teaching Hospital were chosen by systematic randomized selection. Different screening tests for detecting neuropathy in diabetic foot such as symptom and sign scores, Michigan Neuropathy Disability Score (MNDS), and testing by a monofilament were performed for each patient.

RESULTS

According to the neuropathy symptom score, 54.9% of the patients were neuropathic, their score was higher than 5, and by neuropathy sign score, 10.1% were neuropathic with a score higher than 6. Regarding MNDS, 42.7% of the subjects were neuropathic, with a score higher than 3. Finally, 23.9% were unable to sense at least one point in the monofilament examination.

CONCLUSIONS

There were obvious differences between the results of different methods in our study. However, there were significant correlations between them, except between sign and symptom score methods. For determining the most reliable screening test, further studies are needed to compare these methods with a gold standard test and reveal the specificity and sensitivity of these tests.

Effectiveness of Semmes-Weinstein monofilament examination for diabetic peripheral neuropathy screening

OBJECTIVE

To evaluate the effectiveness of the Semmes-Weinstein monofilament examination (SWME) for diabetic peripheral neuropathy (DPN) screening at an outpatient clinic.

METHODS

Eighty-two type 2 diabetic outpatients were questioned about 13 subjective symptoms and tested for deep reflexes. They were examined using two types of quantitative sensory testing: SWME (using 4.31/2 g and 5.07/10 g monofilaments) and vibration testing (using the C-64 quantitative tuning fork). The patients were diagnosed with DPN when two of the following three criteria from both legs were met: (1) the presence of either pain, numbness, or paraesthesia; (2) a diminished or absent ankle reflex; or (3) a scale below 4 for their vibration perception thresholds (VPT).

RESULTS

The most common subjective symptoms were muscle cramps and numbness in the extremities. SWME 4.31/2 g at the great toe or the plantar aspect of the fifth metatarsal was the most useful diagnostic test for DPN, providing 60.0% sensitivity and 73.8% specificity. SWME 4.31/2 g was correlated with lower limb VPT (P=.029) and three subjective symptoms including fainting. SWME 5.07/10 g was correlated with lower limb VPT (P=.011), the ankle reflex (P=.013), the knee reflex (P=.031), and two subjective symptoms. However, the sensitivity to diagnose DPN was low (30.0%).

CONCLUSIONS

The abnormalities indicated by SWME correlated well with those identified by lower limb VPT. Moreover, SWME 4.31/2 g correlated with fainting, suggesting that it could detect abnormalities in the small fibers. Considering the minimal time for this examination, SWME 4.31/2 g is a useful examination in an outpatient setting along with lower limb VPT and ankle reflex testing.