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Background: Muscle-specific tyrosine kinase (MuSK) autoantibody-positive (Ab+) generalised myasthenia gravis (gMG) is a rare and frequently severe subtype of gMG. Objectives: To assess the efficacy and safety of rozanolixizumab in the subgroup of patients with MuSK Ab+ gMG in the MycarinG study. Design: A randomised, double-blind, placebo-controlled phase III study. Methods: Patients with acetylcholine receptor (AChR) Ab+ or MuSK Ab+ gMG (aged ⩾18 years, Myasthenia Gravis Foundation of America Disease Class II–IVa, Myasthenia Gravis Activities of Daily Living [MG-‍ADL] score ⩾3.0 [non-ocular symptoms], Quantitative Myasthenia Gravis score ⩾11.0) were randomly assigned (1:1:1) to receive once-weekly subcutaneous infusions of rozanolixizumab 7 mg/kg, rozanolixizumab 10 mg/kg or placebo for 6 weeks, followed by an 8-week observation period. Randomisation was stratified by AChR and MuSK autoantibody status. The primary study endpoint was change from baseline to Day 43 in MG-ADL score. Treatment-emergent adverse events (TEAEs) were also assessed. Results: Overall, 200 patients were randomised, of whom 21 had MuSK Ab+ gMG and received rozanolixizumab 7 mg/kg ( n = 5), 10 mg/kg ( n = 8) or placebo ( n = 8). In patients with MuSK Ab+ gMG, reductions from baseline to Day 43 in MG-ADL scores were observed: rozanolixizumab 7 mg/kg least squares mean (LSM) change (standard error), –7.28 (1.94); 10 mg/kg, –4.16 (1.78); and placebo, 2.28 (1.95). Rozanolixizumab 7 mg/kg LSM difference from placebo was −9.56 (97.5% confidence interval: −15.25, −3.87); 10 mg/kg, −6.45 (−11.03, –1.86). TEAEs were experienced by four (80.0%), five (62.5%) and three (37.5%) patients with MuSK Ab+ gMG receiving rozanolixizumab 7 mg/kg, 10 mg/kg and placebo, respectively. No patients experienced serious TEAEs. No deaths occurred. Conclusion: This subgroup analysis of adult patients with MuSK Ab+ gMG enrolled in the MycarinG study supports the use of rozanolixizumab as an effective treatment option for patients with gMG who have MuSK autoantibodies. Trial registration: ClinicalTrials.gov: NCT03971422 ( https://clinicaltrials.gov/study/NCT03971422 ); EU Clinical Trials Register: EudraCT 2019-000968-18 ( https://www.clinicaltrials‌register.eu/ctr-search/trial/2019-000968-18/GB ).

Aim: Several studies have found subcutaneous (SC) and intravenous (IV) administration of similar drugs for long-lasting immunological and autoimmune diseases to have similar clinical effectiveness, meaning that what patients report they prefer is, or should be, a major factor in treatment choices. Therefore, it is important to systematically compile evidence regarding patient preferences, treatment satisfaction and health-related quality of life (HRQL) using SC or IV administration of the same drug. Materials & methods: PubMed database searches were run on 15 October 2021. Studies involving patients with experience of both home-based SC and hospital-based IV administration of immunoglobulins or biological therapies for the treatment of any autoimmune disease or primary immunodeficiencies (PIDs) were included. The outcomes assessed were patient preferences, treatment satisfaction and HRQL. Preference data were meta-analyzed using a random-effects model. Results: In total, 3504 citations were screened, and 46 publications describing 37 studies were included in the review. There was a strong overall preference for SC over IV administration, with similar results seen for PIDs and autoimmune diseases: PID, 80% (95% confidence interval [CI], 64–94%) preferred SC; autoimmune diseases, 83% (95% CI: 73–92%); overall, 82% (95% CI: 75–89%). The meta-analysis also found that 84% (95% CI: 75–92%) of patients preferred administration at home to treatment in hospital. Analysis of treatment satisfaction using the life quality index found consistently better treatment interference and treatment setting scores with SC administration than with IV administration. Conclusion: Compared with IV infusions in hospital, patients tend to prefer, to be more satisfied with and to report better HRQL with SC administration of the same drug at home, primarily due to the greater convenience. This study contributes to evidence-based care of patients with autoimmune diseases or PIDs.

Abstract Objectives To assess the safety, tolerability, and key pharmacodynamic effects of subcutaneous batoclimab, a fully human anti‐neonatal Fc receptor monoclonal antibody, in patients with generalized myasthenia gravis and anti‐acetylcholine receptor antibodies. Methods A Phase 2a, proof‐of‐concept, randomized, double‐blind, placebo‐controlled trial is described. Eligible patients were randomized (1:1:1) to receive once‐weekly subcutaneous injections of batoclimab 340 mg, batoclimab 680 mg, or matching placebo for 6 weeks. Subsequently, all patients could enter an open‐label extension study where they received batoclimab 340 mg once every 2 weeks for 6 weeks. Primary endpoints were safety, tolerability, and change from baseline in total immunoglobulin G, immunoglobulin G subclasses, and anti‐acetylcholine receptor antibodies at 6 weeks post‐baseline. Secondary endpoints included changes from baseline to 6 weeks post‐baseline for Myasthenia Gravis Activities of Daily Living, Quantitative Myasthenia Gravis, Myasthenia Gravis Composite, and revised 15‐item Myasthenia Gravis Quality of Life scores. Results Seventeen patients were randomized to batoclimab 680 mg (n = 6), batoclimab 340 mg (n = 5), or placebo (n = 6). Batoclimab was associated with significantly greater reductions in total immunoglobulin G and anti‐acetylcholine receptor antibodies from baseline to 6 weeks post‐baseline than placebo. Reductions in immunoglobulin G subclasses were generally consistent with total immunoglobulin G. While clinical measures showed directionally favorable improvements over time, the study was not powered to draw conclusions about therapeutic efficacy. No safety issues were identified. Interpretation The safety profile, pharmacodynamics, and preliminary clinical benefits observed in this study support further investigation of subcutaneous batoclimab injections as a potential patient‐administered therapy for seropositive generalized myasthenia gravis.

ObjectiveTo establish a simple electrophysiological scale for patients with distal symmetric axonal polyneuropathy, in order to promote standardized and informative electrodiagnostic reporting, and understand the complex relationship between electrophysiological and clinical polyneuropathy severity.MethodsWe included 76 patients with distal symmetric axonal polyneuropathy, from a cohort of 151 patients with polyneuropathy prospectively recruited from November 2016 to May 2017. Patients underwent nerve conduction studies (NCS), were evaluated by the Toronto Clinical Neuropathy Score (TCNS), and additional tests. The number of abnormal NCS parameters was determined, within the range of 0-4, considering low amplitude or conduction velocity in the sural and peroneal nerve.ResultsHigher number of NCS abnormalities was associated with higher TCNS, indicating more severe polyneuropathy. Polyneuropathy severity per the TCNS was most frequently (63%-70%) mild in patients with a low (0-1) number of NCS abnormalities, and most frequently (57%-67%) severe in patients with a high number (3-4) of NCS abnormalities, while patients with an intermediate (2) number of NCS abnormalities showed mainly mild and moderate severity with equal distribution (40%).ConclusionsA simple NCS classification system can objectively grade polyneuropathy severity, although significant overlap exists especially at the intermediate range, underscoring the importance of clinical based scoring.

ObjectiveADAPT+ assessed the long-term safety, tolerability, and efficacy of efgartigimod in adult participants with generalized myasthenia gravis (gMG).MethodsADAPT+ was an open-label, single-arm, multicenter, up to 3-year extension of the pivotal phase 3 ADAPT study. Efgartigimod was administered in treatment cycles of 4 intravenous infusions (one 10 mg/kg infusion per week). Initiation of subsequent treatment cycles was individualized based on clinical evaluation. Safety endpoints included incidence and severity of adverse events. Efficacy endpoints assessed disease severity using Myasthenia Gravis-Activities of Daily Living (MG-ADL) and Quantitative Myasthenia Gravis (QMG) scores.ResultsAs of January 2022, 151 participants had rolled over to ADAPT+ and 145 had received ≥1 dose of efgartigimod, of whom, 111 (76.6%) were AChR-Ab+ and 34 (23.4%) were AChR-Ab−. Mean study duration (treatment plus follow-up) was 548 days, and participants received up to 17 treatment cycles, corresponding to 217.6 participant-years of exposure. In the overall population, 123 (84.8%) participants reported ≥1 treatment-emergent adverse event; most frequent were headache (36 [24.8%]), COVID-19 (22 [15.2%]), and nasopharyngitis (20 [13.8%]). Clinically meaningful improvement (CMI) in mean MG-ADL and QMG scores was seen as early as 1 week following the first infusion across multiple cycles in AChR-Ab+ and AChR-Ab− participants. Maximal MG-ADL and QMG improvements aligned with onset and magnitude of total IgG and AChR-Ab reductions. For AChR-Ab+ participants at any time point in each of the first 10 treatment cycles, more than 90% had a maximum reduction of ≥2 points (CMI) in MG-ADL total score; across the 7 cycles in which QMG was measured, 69.4% to 91.3% of participants demonstrated a maximum reduction of ≥3 points (CMI) in QMG total score. Many participants demonstrated improvements well beyond CMI thresholds. In AChR-Ab+ participants with ≥1 year of combined follow-up between ADAPT and ADAPT+, mean number of annualized cycles was 4.7 per year (median [range] 5.0 [0.5–7.6]).ConclusionResults of ADAPT+ corroborate the substantial clinical improvements seen with efgartigimod in ADAPT and support its long-term safety, tolerability, and efficacy, as well as an individualized dosing regimen for treatment of gMG.Clinical trial registrationhttps://classic.clinicaltrials.gov/ct2/show/NCT03770403, NCT03770403.

Abstract Background We have aimed to assess whether muscle thickness ultrasound (US) shows differences between patients with chronic inflammatory demyelinating polyneuropathy (CIDP), chronic axonal polyneuropathy (CAP), and other neuromuscular (NM) diseases compared to controls and to each other. Methods We performed a cross-sectional study from September 2021 to June 2022. All subjects underwent quantitative sonographic evaluation of muscle thickness in eight relaxed muscles and four contracted muscles. Differences were assessed using multivariable linear regression, correcting for age and body mass index (BMI). Results The study cohort consisted of 65 healthy controls, and 95 patients: 31 with CIDP, 34 with CAP, and 30 with other NM diseases. Both relaxed and contracted muscle thickness in all patient groups were lower than in the healthy controls, after controlling for age and body mass index (BMI). Regression confirmed that the differences persisted between patient groups and healthy controls. Differences between patient groups were not apparent. Conclusion The current study shows that muscle ultrasound thickness is not specific in NM disorders, but shows a global reduction in thickness compared with healthy controls after corrections for age and BMI.

Myasthenia gravis (MG) is an autoimmune disorder characterized by autoantibodies specifically directed against proteins located within the postsynaptic membrane of the neuromuscular junction. These pathogenic autoantibodies can be reduced by therapies such as plasma exchange, IVIG infusions and other immunosuppressive agents. However, there are significant side effects associated with most of these therapies. Since there is a better understanding of the molecular structure and the biological properties of the neonatal Fc receptors (FcRn), it possesses an attractive profile in treating myasthenia gravis. FcRn receptors prevent the catabolism of IgG by impeding their lysosomal degradation and facilitating their extracellular release at physiological pH, consequently extending the IgG half-life. Thus, the catabolism of IgG can be enhanced by blocking the FcRn, leading to outcomes similar to those achieved through plasma exchange with no significant safety concerns. The available studies suggest that FcRn holds promise as a versatile therapeutic intervention, capable of delivering beneficial outcomes in patients with distinct characteristics and varying degrees of MG severity. Efgartigimod is already approved for the treatment of generalized MG, rozanolixizumab is under review by health authorities, and phase 3 trials of nipocalimab and batoclimab are underway. Here, we will review the available data on FcRn therapeutic agents in the management of MG.

IntroductionThe patient acceptable symptom state (PASS) is a reliable way to characterize a patient’s satisfaction with their disease state in a “Yes”/“No” dichotomous manner. There is limited data on the time required to reach an acceptable state in Myasthenia Gravis (MG). We aimed to determine the time to reach a first PASS “Yes” response in patients at MG diagnosis and a PASS “No” status, and also to determine the influence of various factors on this time.MethodsWe performed a retrospective study of patients diagnosed with myasthenia gravis who had an initial PASS “No” response and defined the time to reach a first PASS “Yes” by Kaplan–Meier analysis. Correlations were made between demographics, clinical characteristics, treatment and disease severity, using the Myasthenia Gravis Impairment Index (MGII) and Simple Single Question (SSQ).ResultsIn 86 patients meeting inclusion criteria, the median time to PASS “Yes” was 15 months (95% CI 11–18). Of 67 MG patients who achieved PASS “Yes,” 61 (91%), achieved it by 25 months after diagnosis. Patients who required only prednisone therapy achieved PASS “Yes” in a shorter time with a median of 5.5 months (p = 0.01). Very-late-onset MG patients reached PASS “Yes” status in a shorter time (HR = 1.99, 95% CI 0.26–2.63; p = 0.001).DiscussionMost patients reached PASS “Yes” by 25 months after diagnosis. MG patients who only required prednisone and those with very-late-onset MG reach PASS “Yes” in shorter intervals.

Abstract Background Hereditary transthyretin amyloidosis is an uncommon multisystem disorder caused by mutation of the transthyretin protein, leading to peripheral neuropathy often with autonomic features, cardiomyopathy, or a mixed phenotype. Multiple other organ systems can be involved with ophthalmologic, renal, hematologic, gastrointestinal, and/or genitourinary symptoms and signs. This often results in assessments by multiple specialists and significant delays before the diagnosis is recognized. With the recent advent of potentially lifesaving therapies, early diagnosis has become even more important. Our case highlights the protean aspects of this disease as well as the difficulty of making this diagnosis, especially in the absence of a clear family history. Case presentation We report the case of a 64-year-old man of East-Asian descent who presented with diarrhea, mild anemia, and symptoms of peripheral neuropathy. Numerous investigations and specialist evaluations did not identify a cause. Progression of neurologic symptoms and the development of new hematologic abnormalities ultimately led to consideration of hereditary transthyretin amyloidosis. The diagnosis was confirmed after re-examining previously acquired gastrointestinal biopsies and pursuing genetic testing, which confirmed a pathogenic mutation in the transthyretin gene. He was subsequently started on a novel gene-silencing therapy. On clinical follow-up 8 months after initiation of therapy, the patient described stabilization of previously progressive numbness, weakness, and weight loss with an unchanged neurologic examination and stable repeat electrophysiologic testing. Conclusions Hereditary transthyretin amyloidosis is a challenging disease to recognize in early stages owing to its multisystem and nonspecific manifestations. Recent approval of novel therapies highlights the importance of early diagnosis before irreversible organ damage occurs.

IntroductionLoss of muscle thickness can be demonstrated in a wide spectrum of neuromuscular disorders, while fasciculations are more frequent in amyotrophic lateral sclerosis (ALS). In the current study, we aimed to determine the sensitivity and specificity of quantitative sonographic assessment of muscle thickness and the presence of fasciculations for diagnosing various neuromuscular disorders.MethodsThe thickness and the presence of fasciculations in eight muscles were determined by sonography in patients with myopathy (22), polyneuropathy (36), ALS (91), and spinal muscular atrophy (SMA) (31) and compared to normative values determined in 65 heathy control subjects.ResultsReduced muscle thickness in at least one relaxed muscle showed 92-100% sensitivity for diagnosing a neuromuscular disease, with a specificity of 85% for differentiating patients from heathy controls (AUC = 0.90). Subtracting distal from proximal muscle thickness may differentiate between myopathy and polyneuropathy. Fasciculations in ≥1 proximal muscle showed good diagnostic accuracy (AUC = 0.87) for diagnosing ALS.DiscussionSonographic assessment of muscle thickness is a sensitive tool for diagnosing a wide spectrum of neuromuscular diseases, and may facilitate diagnosis even in patients with normal strength on neurological examination, while the presence of fasciculations in proximal muscles may facilitate ALS diagnosis.

Abstract The two main objectives of this analysis were to (i) characterize the relationship between immunoglobulin (Ig) exposure and chronic inflammatory demyelinating polyneuropathy (CIDP) disease severity using data from 171 patients with CIDP who received either subcutaneous Ig (IgPro20; Hizentra®) or placebo (PATH study), and to (ii) simulate and compare exposure coverage with various dosing approaches considering weekly dosing to be the reference dose. IgG pharmacokinetic (PK) parameters, including those from a previous population PK model, were used to predict individual IgG profile and exposure metrics. Treatment‐related changes in Inflammatory Neuropathy Cause and Treatment (INCAT) scores were best described by a maximum effect (Emax) model as a function of ΔIgG (total serum IgG at INCAT score assessment minus baseline IgG levels before intravenous Ig restabilization). Simulations indicate that flexible dosing from daily to biweekly (every other week) provide an exposure coverage equivalent to that of a weekly Ig dose.

Abstract Background The global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causing the ongoing coronavirus disease 2019 (COVID-19) pandemic has raised serious concern for patients with chronic disease. A correlation has been identified between the severity of COVID-19 and a patient’s preexisting comorbidities. Although COVID-19 primarily involves the respiratory system, dysfunction in multiple organ systems is common, particularly in the cardiovascular, gastrointestinal, immune, renal, and nervous systems. Patients with amyloid transthyretin (ATTR) amyloidosis represent a population particularly vulnerable to COVID-19 morbidity due to the multisystem nature of ATTR amyloidosis. Main body ATTR amyloidosis is a clinically heterogeneous progressive disease, resulting from the accumulation of amyloid fibrils in various organs and tissues. Amyloid deposition causes multisystem clinical manifestations, including cardiomyopathy and polyneuropathy, along with gastrointestinal symptoms and renal dysfunction. Given the potential for exacerbation of organ dysfunction, physicians note possible unique challenges in the management of patients with ATTR amyloidosis who develop multiorgan complications from COVID-19. While the interplay between COVID-19 and ATTR amyloidosis is still being evaluated, physicians should consider that the heightened susceptibility of patients with ATTR amyloidosis to multiorgan complications might increase their risk for poor outcomes with COVID-19. Conclusion Patients with ATTR amyloidosis are suspected to have a higher risk of morbidity and mortality due to age and underlying ATTR amyloidosis-related organ dysfunction. While further research is needed to characterize this risk and management implications, ATTR amyloidosis patients might require specialized management if they develop COVID-19. The risks of delaying diagnosis or interrupting treatment for patients with ATTR amyloidosis should be balanced with the risk of exposure in the health care setting. Both physicians and patients must adapt to a new construct for care during and possibly after the pandemic to ensure optimal health for patients with ATTR amyloidosis, minimizing treatment interruptions.

ObjectiveTo investigate the contribution of duration and temporal dispersion (TD) of the distal compound muscle action potential (CMAP) in discriminating chronic inflammatory demyelinating polyneuropathy (CIDP) from diabetic sensorimotor polyneuropathy (DSP) and from CIDP+DSP.MethodsWe performed a retrospective review of patients diagnosed with CIDP, DSP and CIDP+DSP (responsive to immunotherapy) and examined differences in CMAP duration and TD at baseline.ResultsWe included 59 subjects: 17 CIDP, 21 DSP and 21 CIDP+DSP. Of these, 16 (94.1%) CIDP, 18 (85.7%) CIDP+DSP and 1 (4.7%) DSP fulfilled the 2010 EFNS/PNS criteria for definite CIDP. There was no difference in CMAP duration or TD in all nerves (compound outcome) or in individual motor nerves. Patients with CIDP/CIDP+DSP had more conduction blocks, slower conduction velocities and more prolonged F wave latencies than those with DSP.ConclusionMeasures of CMAP duration and TD were not helpful in distinguishing CIDP, DSP or CIDP+DSP patients; however, parameters such as F-wave latencies, conduction blocks or the number of demyelinating parameters were useful in this separation.SignificanceThere are no definite nerve conduction criteria to distinguish patients with CIDP+DSP from DSP alone. Further studies focusing on measures of demyelination may provide stronger evidence to guide treatment decisions in CIDP + DSP patients.

Abstract Background Psychopathology and personality traits may influence the course of autoimmune disorders. With this prospective longitudinal cohort study, we aimed to assess personality, stress and depression in myasthenia patients who relapse and those who remain stable or improve (non-relapsers). Method We collected data from 155 consecutive adult patients with confirmed MG attending the Neuromuscular Clinic, Toronto General Hospital, between March 2017 and July 2018, for this study. Patients were assessed at baseline and 6 months, or at the time of MG relapse. At both visits, the patients were assessed clinically and were asked to complete self-administered questionnaires for disease severity, chronic stress and depression. Personality type was assessed at baseline only. Relapsing patients were defined as those patients with MGII score increasing by more than 5.5 points from visit 1 to visit 2. Results Relapsers had higher baseline scores for depression (p = 0.01) and the change in disease severity correlated with the change in depression score (r = 0.2534, p = 0.0015, 95% CI: 0.098 0.3961). Higher levels of stress at baseline and neuroticism predicted higher relapse rates (p = 0.01 and p

Electrophysiological studies are essential for the diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP), but the utility of nerve conduction studies in monitoring outcomes in individual CIDP patients is controversial. Electrophysiological improvements after short-term treatment have been described in large cohorts of CIDP patients, but the magnitude of the changes is small and might be obscured in individual patients due to the variation inherent in nerve conduction testing. We present the case of a CIDP patient treated successfully with immunosuppression and followed for 31 years with serial standardized clinical and electrophysiological evaluations. Improvement in electrophysiological parameters lagged clinical changes for up to 2 years, but all motor parameters improved (distal motor and F wave latencies, conduction velocities, and compound muscle action potential amplitudes) even with evidence of initial axonal damage. Worsening of electrophysiological parameters, specifically increasing F wave latencies, heralded clinical relapse by as much as a year. Electrophysiological parameters do improve with treatment in CIDP patients, although the changes can take up to 2 years, and also worsening electrophysiological parameters can herald clinical relapse and might help guide therapeutic decisions.

Abstract. Introduction:. Trauma and compression are common causes of peripheral neuropathic pain (NP) refractory to conventional medical management (CMM). The role of perineural interventions in relieving this type of pain is unclear. Objectives:. The objectives of this retrospective study were to determine the analgesic benefits of adding a combination of perineural local anesthetic and steroids (LA-S) to CMM compared with CMM alone in patients who had moderate-to-severe refractory NP after trauma to the ankle and the foot. Methods:. Health care records of 60 patients in exposed (3 injections of perineural LA-S at weekly intervals with CMM) and 60 in unexposed (CMM) cohorts were reviewed. Data on patient characteristics, pain, and mental and physical function were extracted at baseline and at the postintervention follow-up. Data were analyzed to evaluate analgesic benefit from the study interventions and the impact of baseline characteristics. Results:. Perineural LA-S with CMM cohort had lower pain numerical rating scale scores at 1 to 3 months after the intervention as compared to the CMM alone cohort (5.50 [interquartile range 4.00–7.00] and 7.00 [interquartile range 5.00–8.00], respectively; P < 0.01). However, multivariable analysis did not show an independent beneficial analgesic effect with the addition of perineural LA-S to CMM compared with CMM alone. A greater severity of preintervention catastrophizing (each unit increase in pain catastrophizing score increased pain score at follow-up by 0.04, 95% confidence interval: 0.01–0.07) was associated with reduction in the analgesic benefit. Conclusion:. Perineural local anesthetic and steroid injections do not confer an analgesic benefit for trauma- or compression-related peripheral NP.

Introduction: Glomerular filtration rate (GFR) is routinely used for clinical assessment of kidney function. However, the accuracy of estimating equations in older adults is uncertain. Methods: In 66 adults with ≥50 years type 1 diabetes (T1D) duration and 73 nondiabetic controls from age/sex-matched subgroups (65 ± 8 years old and 77[55%] were women) we evaluated the performance of estimated GFR (eGFR) by creatinine (Modification of Diet and Renal Disease [MDRD], Chronic Kidney Disease–Epidemiology [CKD-EPI]cr), cystatin C (CKD-EPIcys, CKD-EPIcr-cys), and β2-microglobulin (β2M) compared with measured GFR by inulin clearance (mGFR). Performance was evaluated using metrics of bias (mean difference), precision (SD), and accuracy (proportion of eGFR that differed by >20% of mGFR). Results: Mean mGFR was 104 ± 18 ml/min per 1.73 m2 (range: 70–154 ml/min per 1.73 m2) and was not different between T1D and controls (103 ± 17 vs. 105 ± 19 ml/min per 1.73 m2, P = 0.39). All equations significantly underestimated mGFR (bias: −15 to −30 ml/min per 1.73 m2, P < 0.001 for all comparisons) except for β2M, which had bias of 1.9 ml/min per 1.73 m2 (P = 0.61). Bias was greatest in cystatin C–based equations. Precision was lowest for β2M (SD: 43.5 ml/min per 1.73 m2, P < 0.001 for each comparison). Accuracy was lowest for CKD-EPIcysC (69.1%, P < 0.001 for each comparison). Cystatin C–based equations demonstrated greater bias and lower accuracy in older age subgroups (

The porphyrias are metabolic disorders due to a defect in the heme biosynthetic pathway. Patients have diverse clinical presentations with neuropathy being frequent in acute intermittent porphyria (AIP). Associated symptoms are abdominal pain and seizures. Three patients presenting with neuropathy were later diagnosed with AIP on the basis of clinical features, erythrocyte porphobilinogen deaminase activity, neuropathic patterns, and nerve conduction studies. Testing for the HMBS genetic mutation confirmed the diagnosis of AIP in 1 patient. The findings from this case series confirm that porphyric neuropathy in AIP is a predominantly motor neuropathy with differing neuropathic presentations ranging from focal motor neuropathy to quadriplegia and respiratory failure.

Objectives: Diabetic kidney disease (DKD) is an independent predictor of cardiovascular morbidity and mortality in type 1 diabetes (T1D). We aimed to explore clinical and biochemical factors, including the achievement of American Diabetes Association (ADA) recommended targets associated with DKD in people living with T1D for ≥50 years. Methods: This was a post hoc analysis of a cross-sectional study of 75 participants enrolled in the Canadian Study of Longevity in T1D. We explored diabetes-related complications, including neuropathy, retinopathy, cardiovascular disease, and DKD. Study participants were dichotomized based on the achievement of ADA recommended targets as the low-target group (achieving ≤4 targets, n = 31) and high-target group (achieving >4 targets, n = 44). The outcome of interest was DKD defined by estimated glomerular filtration rate (eGFR) values 30 mg. Multivariable logistic regression models were employed to estimate odds ratios (ORs) for DKD with 95% confidence intervals (CIs). Results: Of the 75 participants with prolonged T1D duration (45% male, mean age 66 years), 25 participants had DKD and 50 did not. There was no statistical difference between the high- and low-target groups in terms of age and body mass index. eGFR was significantly higher and the prevalence of diabetic retinopathy was significantly lower in the high-target group. Older age at diagnosis of T1D and lower frequency component to high-frequency component ratio increased the odds of having DKD. Conclusions: In adults with prolonged T1D duration, older age at diagnosis and lower heart rate variability may be associated with DKD.

The variants of chronic inflammatory demyelinating polyneuropathy (CIDP) differ not just in their clinical, pathological and electrophysiological characteristics, but often in their indifferent response to conventional immunosuppressive agents which are effective in typical CIDP. High quality evidence is lacking as far as the management of these atypical variants is concerned. In this review, we summarize the treatment approaches to each of these CIDP variants based on existing data. Distal acquired demyelinating symmetric polyneuropathy (DADS) has the phenotype of a symmetric, demyelinating sensory, length-dependent polyneuropathy and is frequently associated with paraproteinemia and anti myelin associated glycoprotein (MAG) antibodies. While the management of idiopathic DADS (DADS-I) is the same as CIDP, DADS-M responds suboptimally and has a favorable response to rituximab. Multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) manifests as a chronic progressive demyelinating mononeuropathy multiplex which can evolve to a confluent pattern indistinguishable from CIDP. Evidence favors treating MADSAM with conventional immunomodulatory therapy (IMT), but this disorder responds less favorably than CIDP. Some patients present with purely sensory symptoms, known as pure sensory CIDP or chronic inflammatory sensory polyradiculoneuropathy (CISP), the latter localizing to a pre-ganglionic pathology. Both respond well to first line IMT, particularly to intravenous immunoglobulin (IVIG), but patients relapse without maintenance therapy. Pure motor CIDP resembles multifocal motor neuropathy with conduction block (MMNCB), but the previously reported worsening status after steroid treatment was not reproduced in recent studies, and IVIG remains the first-line therapy. Some focal forms of CIDP defy exact classification, but respond well to first-line IMT including IVIG. Overall, atypical CIDP responds to treatment with first-line IMT, but has a suboptimal response compared to CIDP. There is evidence for effectiveness with agents such as rituximab, especially in DADS-M, and this medication can also be used in cases refractory to conventional IMTs. Rituximab is also effective in CIDP with IgG4 antibodies which has distinct clinical features and is mostly refractory to first-line IMT.

Myasthenia gravis (MG) is the prototypical autoimmune disorder caused by specific autoantibodies at the neuromuscular junction. Broad-based immunotherapies, such as corticosteroids, azathioprine, mycophenolate, tacrolimus, and cyclosporine, have been effective in controlling symptoms of myasthenia. While being effective in a majority of MG patients many of these immunosuppressive agents are associated with long-term side effects, often intolerable for patients, and take several months to be effective. With advances in translational research and drug development capabilities, more directed therapeutic agents that can alter the future of MG treatment have been developed. This review focuses on the aberrant immunological processes in MG, the novel agents that target them along with the clinical evidence for efficacy and safety. These agents include terminal complement C5 inhibitors, Fc receptor inhibitors, B cell depleting agents (anti CD 19 and 20 and B cell activating factor [BAFF)]inhibitors), proteosome inhibitors, T cells and cytokine based therapies (chimeric antigen receptor T [CART-T] cell therapy), autologous stem cell transplantation, and subcutaneous immunoglobulin (SCIG). Most of these new agents have advantages over conventional immunosuppressive treatment (IST) for MG therapy in terms of faster onset of action, favourable side effect profile and the potential for a sustained and long-term remission.

High intensity focused ultrasound (HIFU) is a form of thermal ablation technique, which can treat a variety of medical afflictions. One promising therapeutic use is the permanent destruction of nerves non-invasively in patients with severe spasticity or certain types of pain (e.g., phantom limb pain). To this end, HIFU requires ultrasound guidance, which allows the non-invasive, target-specific deposition of thermal energy to the targeted nerve, thereby blocking axonal conduction. In this paper, a composite system comprising both ultrasound-imaging and HIFU therapy was developed and used to induce localized non-invasive nerve blockage in an in vivo large animal study. Five pigs were used with the femoral nerve as the target. Calibrated needle thermocouples inserted at the target site were employed to monitor the target tissue temperature. The degree of nerve blockage was assessed by measuring compound action potential (CAP) signal with a clinical nerve electrophysiology system before and after HIFU exposures. An average CAP signal amplitude reduction of 49% of baseline with a standard deviation of 9% was observed after 20-30 min post exposure. These results demonstrate the feasibility of the proposed ultrasound-guided HIFU modality as a potential non-invasive nerve ablation method.

Point-of-care nerve conduction devices (POCD) have been studied in younger patients and may facilitate screening for polyneuropathy in non-specialized clinical settings. However, performance may be impaired with advanced age owing to age-related changes in nerve conduction. We aimed to evaluate the validity of a POCD as a proxy for standard nerve conduction studies (NCS) in older adults with type 1 diabetes (T1D).Sural nerve amplitude potential (AMP) and sural nerve conduction velocity (CV) was measured in 68 participants with ≥ 50 years T1D duration and 71 controls (from age/sex-matched subgroups) using POCD and NCS protocols. Agreement was determined by the Bland-Altman method, and validity was determined by receiver operating characteristic curves.T1D were 53% female, aged 66±8yr and had diabetes duration 54yr[52,58]. Controls were 56%(p = 0.69) female and aged 65±8yr(p = 0.36). Mean AMPPOCD and CVPOCD for the 139 participants was 7.4±5.8μV and 45.7±11.2m/s and mean AMPNCS and CVNCS was 7.2±6.1μV and 43.3±8.3m/s. Mean difference of AMPPOCD-AMPNCS was 0.3±3.8μV and was 2.3±8.5m/s for CVPOCD-CVNCS. A AMPPOCD of ≤6μV had 80% sensitivity and 80% specificity for identifying abnormal AMPNCS, while a CVPOCD of ≤44m/s had 81% sensitivity and 82% specificity to identify abnormal CVNCS. Abnormality in AMPPOCD or CVPOCD was associated with 87% sensitivity, while abnormality in both measures was associated with 97% specificity for polyneuropathy identification.The POCD has strong agreement and diagnostic accuracy for identification of polyneuropathy in a high-risk subgroup and thus may represent a sufficiently accurate and rapid test for routinely detecting those with electrophysiological dysfunction.

INTRODUCTION:Polyneuropathy is one of the most prevalent neurologic disorders. Although several studies explored the role of the neurological examination in polyneuropathy, they were mostly restricted to specific subgroups of patients and have not correlated examination findings with symptoms and electrophysiological results. OBJECTIVES:To explore the sensitivity and specificity of different neurological examination components in patients with diverse etiologies for polyneuropathy, find the most sensitive combination of examination components for polyneuropathy detection, and correlate examination findings with symptoms and electrophysiological results. METHODS:Patients with polyneuropathy attending the neuromuscular clinic from 01/2013 to 09/2015 were evaluated. Inclusion criteria included symptomatic polyneuropathy, which was confirmed by electrophysiological studies. 47 subjects with no symptoms or electrophysiological findings suggestive for polyneuropathy, served as controls. RESULTS:The total cohort included 312 polyneuropathy patients, with a mean age of 60±14 years. Abnormal examination was found in 95%, most commonly sensory findings (86%). The most common abnormal examination components were impaired ankle reflexes (74%), vibration (73%), and pinprick (72%) sensation. Combining ankle reflex examination with vibration or pinprick perception had the highest sensitivity, of 88%. The specificities of individual examination component were generally high, excluding ankle reflexes (62%), and vibration perception (77%). Abnormal examination findings were correlated with symptomatic weakness and worse electrophysiological parameters. CONCLUSION:The neurological examination is a valid, sensitive and specific tool for diagnosing polyneuropathy, and findings correlate with polyneuropathy severity. Ankle reflex examination combined with either vibration or pinprick sensory testing is the most sensitive combination for diagnosing polyneuropathy, and should be considered minimal essential components of the physical examination in patients with suspected polyneuropathy.

Small fiber neuropathy might be a part of typical mixed small and large fiber neuropathy, or a distinct entity, affecting exclusively small nerve fibers.Explore the utility of small nerve fiber testing in patients with clinical presentation suggesting small fiber neuropathy, with and without evidence for concomitant large fiber neuropathy.Patients attending the neuromuscular clinic from 2012 to 2015 with a clinical presentation suggesting small nerve fiber impairment, who had Laser Doppler flare imaging (LDIFlare) and quantitative thermal testing (QTT) were evaluated for this study. Patients with clinical or electrophysiological evidence for concomitant large fiber neuropathy were not excluded.The sensitivities of LDIFlare, cooling and heat threshold testing were 64%, 36%, and 0% respectively for clinically highly suggestive small fiber neuropathy, 64%, 56%, and 19% respectively for mixed fiber neuropathy, and 86%, 79%, and 29% respectively for diabetic mixed fiber neuropathy.LDIFlare and cooling thresholds testing are non-invasive small nerve fiber testing modalities, with moderate performance in patients with small and mixed fiber neuropathy, and excellent performance in diabetic mixed fiber neuropathy.

Using ranirestat, an aldose reductase (AR) inhibitor, we investigated the relationship between sorbitol and fructose levels in the sciatic nerve and motor nerve conduction velocity (MNCV) in streptozotocin (STZ)-treated diabetic rats. Ranirestat inhibited rat and recombinant human AR with similar IC50 values and equipotently prevented sorbitol accumulation in rat erythrocytes and sciatic nerves in vitro. One week after STZ administration, sorbitol levels in rat erythrocytes and sciatic nerves significantly increased while MNCV decreased. Oral administration of ranirestat (0.03 – 1.0 mg/kg per day) for 3 weeks dose-dependently decreased the elevated sorbitol and fructose levels in the rat sciatic nerves without affecting blood glucose level. Particularly, at doses of 0.1 mg/kg per day or higher, ranirestat normalized both sorbitol and fructose levels in the sciatic nerves of STZ-treated rats. Ranirestat (0.1 – 1.0 mg/kg per day) also improved the STZ-induced decrease in MNCV in a dose-dependent manner. This improvement correlated with the decrease of sorbitol and fructose levels in the rat sciatic nerves. These findings indicate that ranirestat improves MNCV via normalization of sorbitol and fructose accumulation in the sciatic nerve. Keywords:: ranirestat, aldose reductase inhibitor, sorbitol, fructose, motor nerve conduction velocity (MNCV)

Ranirestat (AS-3201) is a novel aldose reductase (AR) inhibitor with potentially beneficial effects on diabetic sensorimotor polyneuropathy. In this study, we performed a kinetic analysis to determine the mode of inhibition of ranirestat on AR and investigated the effects of ranirestat on sorbitol levels in the sciatic nerves and lens of streptozotocin (STZ)-diabetic rats. We also evaluated the effects on motor nerve conduction velocity (MNCV) in STZ-diabetic rats. Kinetic analyses revealed that the ranirestat inhibition of AR is uncompetitive and reversible. In the sciatic nerve and lens of STZ-diabetic rats, single oral administration of ranirestat slightly reduced sorbitol levels. However, repeated oral administration of ranirestat for 5, 21, or 60 days enhanced the reducing effect of the ranirestat on sorbitol levels in the sciatic nerves and lens of STZ-diabetic rats with maximum effects after 21 days of treatment. Finally, repeated oral administration of ranirestat for 21 or 42 days dose-dependently improved the STZ-induced decrease in MNCV in STZ-diabetic rats. These findings demonstrate that repeated oral administration of ranirestat reduces sorbitol accumulation and improves MNCV in STZ-diabetic rats, indicating that ranirestat is an agent for the management of diabetic sensorimotor polyneuropathy. Keywords:: aldose reductase inhibitor, ranirestat (AS-3201), polyol pathway, motor nerve conduction velocity, streptozotocin-diabetic rat

We investigated the chronic functional and histopathological changes in the sciatic nerve and lens of streptozotocin (STZ)-diabetic rats and evaluated the preventive effects of ranirestat (AS-3201), a potent aldose reductase inhibitor, on these changes. Sorbitol levels in the sciatic nerve and lens, motor nerve conduction velocity (MNCV), and development of cataracts were measured in STZ-diabetic rats given a ranirestat-admixed diet (0.0005%) for 35 weeks. Ranirestat reduced sorbitol accumulation in the sciatic nerve and improved the decrease in MNCV of STZ-diabetic rats. Morphological and morphometric examination of changes in sural nerve revealed that treatment with ranirestat prevented both the deformity of myelinated fibers and the decrease in their axonal and myelin areas (atrophy). Ranirestat also averted the changes in the size frequency histogram of myelinated fibers. Finally, STZ-diabetic rats developed early lens opacities 8 weeks after STZ injection and had cataract by the end of the experimental period. However, in the ranirestat-treated diabetic rats, no lens opacity was observed in any rat throughout the entire experimental period. This study suggests that the polyol pathway plays an important role in the progress of diabetic neuropathy and cataract formation in STZ-diabetic rats. Ranirestat should be a promising agent for the treatment of complications associated with diabetes, especially neuropathy. Keywords:: ranirestat (AS-3201), diabetic neuropathy, cataract, aldose reductase inhibition

Vibration perception threshold (VPT) examination using a neurothesiometer provides objective, sensitive and specific information, and has been utilized mainly in patients with diabetic polyneropathy.Explore the utility of VPT examination in CIDP patients.CIDP subjects attending the Neuromuscular clinic between 01/2013 and 12/2014 were evaluated. Demographic data, clinical history, physical examination, VPT values, and electrophysiologic data from their charts were extracted.70 charts were reviewed. 55 CIDP patients had elevated VPT, associated with higher frequency of abnormal sensory testing for various modalities (92.7% vs. 46.7%, p

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is one of several chronic treatable acquired demyelinating neuropathies.To explore the association between the degree of demyelination in CIDP, and treatment responsiveness.A retrospective chart review of CIDP subjects assessed between 1997 and 2013 was performed to compare treatment responsiveness using different sets of criteria.99 CIDP patients were included, 34 with diabetes mellitus (DM). Treatment responsiveness was higher in CIDP-DM fulfilling 1 or more EFNS/PNS criteria, (63% vs. 31%, p = 0.03), and in CIDP+DM fulfilling 2 or more criteria (89% vs. 36%, p = 0.01). Nonetheless, treatment responsiveness in CIDP+DM had the highest odds ratio (3.73, p = 0.01). Similar results were also shown in simplified uniform study criteria, with 10% cut off values for CIDP-DM, compared to 30% for CIDP+DM.In CIDP+DM, higher degrees of demyelination are associated with treatment responsiveness, implying the need to adjust current criteria in these patients.

In vivo Corneal Confocal Microscopy (IVCCM) is a validated, non-invasive test for diabetic sensorimotor polyneuropathy (DSP) detection, but its utility is limited by the image analysis time and expertise required. We aimed to determine the inter- and intra-observer reproducibility of a novel automated analysis program compared to manual analysis.In a cross-sectional diagnostic study, 20 non-diabetes controls (mean age 41.4±17.3y, HbA1c 5.5±0.4%) and 26 participants with type 1 diabetes (42.8±16.9y, 8.0±1.9%) underwent two separate IVCCM examinations by one observer and a third by an independent observer. Along with nerve density and branch density, corneal nerve fibre length (CNFL) was obtained by manual analysis (CNFLMANUAL), a protocol in which images were manually selected for automated analysis (CNFLSEMI-AUTOMATED), and one in which selection and analysis were performed electronically (CNFLFULLY-AUTOMATED). Reproducibility of each protocol was determined using intraclass correlation coefficients (ICC) and, as a secondary objective, the method of Bland and Altman was used to explore agreement between protocols.Mean CNFLManual was 16.7±4.0, 13.9±4.2 mm/mm2 for non-diabetes controls and diabetes participants, while CNFLSemi-Automated was 10.2±3.3, 8.6±3.0 mm/mm2 and CNFLFully-Automated was 12.5±2.8, 10.9 ± 2.9 mm/mm2. Inter-observer ICC and 95% confidence intervals (95%CI) were 0.73(0.56, 0.84), 0.75(0.59, 0.85), and 0.78(0.63, 0.87), respectively (p = NS for all comparisons). Intra-observer ICC and 95%CI were 0.72(0.55, 0.83), 0.74(0.57, 0.85), and 0.84(0.73, 0.91), respectively (p

IntroductionWe aimed to determine whether the clinical characteristics and electrodiagnostic classification of nerve injury, and response to treatment differed in patients diagnosed with chronic inflammatory demyelinating polyneuropathy (CIDP) with and without diabetes.MethodsCIDP patients with diabetes (CIDP+DM) (n = 67) and without diabetes (CIDP-DM) (n = 67) underwent clinical examination and nerve conduction studies (NCS). CIDP-DM patients were selected using age and gender matching with the existing CIDP+DM cohort. Patients treated with immunotherapies were classified as responders (R) (n = 46) or non-responders (NR) (n = 54) based on clinical response to treatment. The groups were compared using analysis of variance, contingency tables and Kruskal-Wallis analyses.ResultsCIDP+DM subjects had more severe neuropathy based on higher lower limb vibration potential thresholds (VPT)(p = 0.004), higher Toronto Clinical Neuropathy Score (TCNS) (p = 0.0009), more proximal weakness (p = 0.03), more gait abnormality (p = 0.03) and more abnormal NCS. CIDP+DM subjects had more abnormal sural NCS with lower sural sensory nerve action potential amplitudes (2.4±3.0 µV, 6.6±6.0 µV, pDiscussionThe clinical phenotype and electrophysiological profile of CIDP patients differs according to the presence or absence of diabetes. Despite CIDP+DM patients having more severe clinical and electrophysiological neuropathy, they are less likely to receive disease-modifying/specific therapy, yet have similar response rates to treatment as those without diabetes. Specifically, the duration of neuropathy - not diabetes status - was associated with treatment response.

BACKGROUND: Confirmation of diabetic sensorimotor polyneuropathy (DSP) relies on standard nerve conduction studies (NCS) performed in specialized clinics. We explored the utility of a point-of-care device (POCD) for DSP detection by nontechnical personnel and a validation of diagnostic thresholds with those observed in a normative database. RESEARCH DESIGN AND METHODS: 44 subjects with type 1 and type 2 diabetes underwent standard NCS (reference method). Two nontechnical examiners measured sural nerve amplitude potential (SNAP) and conduction velocity (SNCV) using the POCD. Reliability was determined by intraclass correlation coefficients (ICC [2], [1]). Validity was determined by Bland-Altman analysis and receiver operating characteristic curves. RESULTS: The 44 subjects (50% female) with mean age 56 ± 18 years had mean SNAP and SNCV of 8.0 ± 8.6 µV and 41.5 ± 8.2 m/s using standard NCS and 8.0 ± 8.2 µV and 49.9 ± 11.1 m/s using the POCD. Intrarater reproducibility ICC values were 0.97 for SNAP and 0.94 for SNCV while interrater reproducibility values were 0.83 and 0.79, respectively. Mean bias of the POCD was -0.1 ± 3.6 µV for SNAP and +8.4 ± 6.4 m/s for SNCV. A SNAP of ≤6 µV had 88% sensitivity and 94% specificity for identifying age-and height-standardized reference NCS values, while a SNCV of ≤48 m/s had 94% sensitivity and 82% specificity [corrected].. Abnormality in one or more of these thresholds was associated with 95% sensitivity and 71% specificity for identification of DSP according to electrophysiological criteria. CONCLUSIONS: The POCD demonstrated excellent reliability and acceptable accuracy. Threshold values for DSP identification validated those of published POCD normative values. We emphasize the presence of measurement bias--particularly for SNCV--that requires adjustment of threshold values to reflect those of standard NCS.

OBJECTIVE: Compared to recently-studied novel morphological measures, conventional small nerve fiber functional tests have not been systematically studied for identification of diabetic sensorimotor polyneuropathy (DSP). We aimed to determine and compare the diagnostic performance of cooling detection thresholds (CDT) in a cross-sectional type 1 diabetes cohort. RESEARCH DESIGN AND METHODS: 136 subjects with type 1 diabetes and 52 healthy volunteers underwent clinical and electrophysiological examination for DSP classification concomitantly with the Toronto Clinical Neuropathy Score (TCNS) and three small fiber function tests: CDT, heart rate variability (HRV), and laser doppler imaging of axon-mediated neurogenic flare responses to cutaneous heating (LDIFLARE). Area under the curve (AUC) and optimal thresholds were determined by receiver operating characteristic (ROC) curves in the type 1 diabetes cohort. RESULTS: Type 1 diabetes subjects were 42±17 years of age with mean HbA1c 7.9±1.7%. Fifty-nine (45%) met the case definition for DSP. CDT values were lowest in cases with DSP (18.3±8.4°C) compared to controls without DSP (28.4±3.5°C) and to healthy volunteers (29.6±1.8°C; p-value for both comparisons

BACKGROUND:Myasthenia gravis is characterized by weakness and fatigability of different muscle groups, including ocular, bulbar and the limbs. Therefore, a measure of disease severity at the impairment level in myasthenia needs to reflect all the relevant impairments, as well as their variations with activity and fatigue. We conducted a qualitative study of patients with myasthenia, to explore their experiences and related impairments, aimed at developing a conceptual framework of disease severity at the impairment level in myasthenia gravis. METHODS:Twenty patients representing the spectrum of disease participated in semi-structured interviews. Interviews were recorded and the transcripts were analyzed by content analysis using an inductive approach with line-by-line open coding. Themes were generated from these codes. RESULTS:Two main themes were identified: the severity of the impairments and fatigability (i.e., triggering or worsening of an impairment with activity). The impairments were further classified within body regions (ocular, bulbar and axial/limbs). Fatigability was described as a phenomenon affecting the whole body but also affecting specific impairments, and was associated with fluctuation of the symptoms. Patients were concerned that clinical examination at a single point in time might not reflect their true clinical state due to fatigability and fluctuations in severity. CONCLUSIONS:This conceptual framework reflects the relevance of both severity and fatigability in understanding impairment-based disease severity in myasthenia. This framework could inform the development of impairment measures in myasthenia gravis.

OBJECTIVE: Evaluation of diabetic sensorimotor polyneuropathy (DSP) is hindered by the need for complex nerve conduction study (NCS) protocols and lack of predictive biomarkers. We aimed to determine the performance of single and simple combinations of NCS parameters for identification and future prediction of DSP. MATERIALS AND METHODS: 406 participants (61 with type 1 diabetes and 345 with type 2 diabetes) with a broad spectrum of neuropathy, from none to severe, underwent NCS to determine presence or absence of DSP for cross-sectional (concurrent validity) analysis. The 109 participants without baseline DSP were re-evaluated for its future onset (predictive validity). Performance of NCS parameters was compared by area under the receiver operating characteristic curve (AROC). RESULTS: At baseline there were 246 (60%) Prevalent Cases. After 3.9 years mean follow-up, 25 (23%) of the 109 Prevalent Controls that were followed became Incident DSP Cases. Threshold values for peroneal conduction velocity and sural amplitude potential best identified Prevalent Cases (AROC 0.90 and 0.83, sensitivity 80 and 83%, specificity 89 and 72%, respectively). Baseline tibial F-wave latency, peroneal conduction velocity and the sum of three lower limb nerve conduction velocities (sural, peroneal, and tibial) best predicted 4-year incidence (AROC 0.79, 0.79, and 0.85; sensitivity 79, 70, and 81%; specificity 63, 74 and 77%, respectively). DISCUSSION: Individual NCS parameters or their simple combinations are valid measures for identification and future prediction of DSP. Further research into the predictive roles of tibial F-wave latencies, peroneal conduction velocity, and sum of conduction velocities as markers of incipient nerve injury is needed to risk-stratify individuals for clinical and research protocols.

OBJECTIVE: Axon reflex-mediated neurogenic vasodilatation in response to cutaneous heating may reflect early, pre-clinical small fibre dysfunction. We aimed to evaluate the distribution of the vascular flare area measured by laser doppler imaging ("LDI(FLARE) area") in type 1 diabetes and in healthy volunteers. RESEARCH AND METHODS: Concurrent with clinical and electrophysiological examination to classify diabetic sensorimotor polyneuropathy (DSP), LDI(FLARE) area (cm(2)) was determined in 89 type 1 diabetes subjects matched to 64 healthy volunteers. We examined the association and diagnostic performance of LDI with clinical and subclinical measures of DSP and its severity. RESULTS: Compared to the 64 healthy volunteers, the 56 diabetes controls without DSP had significantly lower LDI(FLARE) area (p = 0.006). The 33 diabetes cases with DSP had substantially lower LDI(FLARE) area as compared to controls without DSP (p = 0.002). There was considerable overlap in LDI(FLARE) area between all groups such that the ROC curve had an AUC of 0.72 and optimal sensitivity of 70% for the detection of clinical DSP. Use of a subclinical definition for DSP, according to subclinical sural nerve impairment, was associated with improved AUC of 0.75 and sensitivity of 79%. In multivariate analysis higher HbA1c and body mass index had independent associations with smaller LDI(FLARE) area. CONCLUSIONS: Axon reflex-mediated neurogenic vasodilatation in response to cutaneous heating is a biomarker of early nerve dysfunction in DSP. Its independent association with glycemic exposure in diabetes subjects and both glycemic exposure and BMI in healthy volunteers highlights the existence of small-fibre dysfunction in the natural history of DSP.

BACKGROUND: Though intra-epidermal nerve fiber density (IENFD) is considered the gold standard for diagnosis of small fiber sensory neuropathy (SFSN), we aimed to determine if novel threshold values derived from standard tests of small or large fiber function could serve as diagnostic alternatives. METHODS: Seventy-four consecutive patients with painful polyneuropathy and normal nerve conduction studies (NCS) were defined as SFSN cases or controls by distal IENFD