Spatio-temporal modulation of cortical activity during motor deadaptation depends on the feedback of task-related error

Motor adaptations are responsible for recalibrating actions and facilitating the achievement of goals in an ever-changing environment. Once consolidated, the decay of motor adaptation is a process affected by available sensory information during deadaptation. However, the cortical response to task error feedback during the deadaptation phase has received little attention. Here, we explored changes in brain cortical responses due to feedback of task-related error during deadaptation. Twelve healthy volunteers were recruited for the study. Right hand movement and EEG were recorded during repetitive trials of a hand reaching movement. A visuomotor rotation of 30° was introduced to induce motor adaptation. Volunteers participated in two experimental sessions organized in baseline, adaptation, and deadaptation blocks. In the deadaptation block, the visuomotor rotation was removed, and visual feedback was only provided in one session. Performance was quantified using angle end-point error, averaged speed, and movement onset time. Non-parametric spatiotemporal cluster-level permutation test was used to analyze the EEG recordings. During deadaptation, participants experienced a greater error reduction when feedback of the cursor was provided. The EEG responses showed larger activity in the left centro-frontal parietal areas during the deadaptation block when participants received feedback, as opposed to when they did not receive feedback. Centrally distributed clusters were found for the adaptation and deadaptation blocks in the absence of visual feedback. The results suggest that visual feedback of the task-related error activates cortical areas related to performance monitoring, depending on the accessible sensory information.

Generalized myasthenia gravis with acetylcholine receptor antibodies: A guidance for treatment

BACKGROUND

Generalized myasthenia gravis (MG) with antibodies against the acetylcholine receptor is a chronic disease causing muscle weakness. Access to novel treatments warrants authoritative treatment recommendations. The Nordic countries have similar, comprehensive health systems, mandatory health registers, and extensive MG research.

METHODS

MG experts and patient representatives from the five Nordic countries formed a working group to prepare treatment guidance for MG based on a systematic literature search and consensus meetings.

RESULTS

Pyridostigmine represents the first-line symptomatic treatment, while ambenonium and beta adrenergic agonists are second-line options. Early thymectomy should be undertaken if a thymoma, and in non-thymoma patients up to the age of 50-65 years if not obtaining remission on symptomatic treatment. Most patients need immunosuppressive drug treatment. Combining corticosteroids at the lowest possible dose with azathioprine is recommended, rituximab being an alternative first-line option. Mycophenolate, methotrexate, and tacrolimus represent second-line immunosuppression. Plasma exchange and intravenous immunoglobulin are used for myasthenic crises and acute exacerbations. Novel complement inhibitors and FcRn blockers are effective and fast-acting treatments with promising safety profiles. Their use depends on local availability, refunding policies, and cost-benefit analyses. Adapted physical training is recommended. Planning of pregnancies with optimal treatment, information, and awareness of neonatal MG is necessary. Social support and adaptation of work and daily life activities are recommended.

CONCLUSIONS

Successful treatment of MG rests on timely combination of different interventions. Due to spontaneous disease fluctuations, comorbidities, and changes in life conditions, regular long-term specialized follow-up is needed. Most patients do reasonably well but there is room for further improvement. Novel treatments are promising, though subject to restricted access due to costs.

CRISPR activation to characterize splice-altering variants in easily accessible cells

Genetic variants that affect mRNA splicing are a major cause of hereditary disorders, but the spliceogenicity of variants is challenging to predict. RNA diagnostics of clinically accessible tissues enable rapid functional characterization of splice-altering variants within their natural genetic context. However, this analysis cannot be offered to all individuals as one in five human disease genes are not expressed in easily accessible cell types. To overcome this problem, we have used CRISPR activation (CRISPRa) based on a dCas9-VPR mRNA-based delivery platform to induce expression of the gene of interest in skin fibroblasts from individuals with suspected monogenic disorders. Using this ex vivo splicing assay, we characterized the splicing patterns associated with germline variants in the myelin protein zero gene (MPZ), which is exclusively expressed in Schwann cells of the peripheral nerves, and the spastin gene (SPAST), which is predominantly expressed in the central nervous system. After overnight incubation, CRISPRa strongly upregulated MPZ and SPAST transcription in skin fibroblasts, which enabled splice variant profiling using reverse transcription polymerase chain reaction, next-generation sequencing, and long-read sequencing. Our investigations show proof of principle of a promising genetic diagnostic tool that involves CRISPRa to activate gene expression in easily accessible cells to study the functional impact of genetic variants. The procedure is easy to perform in a diagnostic laboratory with equipment and reagents all readily available.

Efficacy and safety of iscalimab, a novel anti-CD40 monoclonal antibody, in moderate-to-severe myasthenia gravis: A phase 2 randomized study

BACKGROUND

Increased morbidity in many patients with myasthenia gravis (MG) on long-term immunosuppression highlights the need for improved treatments. The aim of this study is to investigate the safety and efficacy of iscalimab (CFZ533), a fully human anti-CD40 monoclonal antibody, in patients with moderate-to-severe MG receiving standard-of-care (SoC) therapies.

METHODS

In this double-blind, placebo-controlled phase 2 study, symptomatic patients (n = 44) despite SoC were randomized 1:1 to receive intravenous iscalimab (10 mg/kg; n = 22) or placebo (n = 22) every 4 weeks for 6 doses in total. Patients were followed up for 6 months after the last dose. The total duration of the study was 52 weeks.

RESULTS

In total, 34 of 44 patients (77.3 %) completed the study. The primary endpoint, Quantitative MG score, did not change significantly between baseline and week 25 for iscalimab (median [90 % CI], -4.07 [-5.67, -2.47]) versus placebo (-2.93 [-4.53, -1.33]); however, non-thymectomized patients (n = 29) showed more favorable results (iscalimab, -4.35 [-6.07, -2.64] vs placebo, -2.26 [-4.16, -0.36]). A statistically significant difference between iscalimab and placebo groups was observed in MG Composite score (adjusted mean change: -4.19 [-6.67, -1.72]; p = 0.007) at week 13, and MG-Activities of Daily Living score (-1.93 [-3.24, -0.62]; p = 0.018) at week 21. Adverse events were comparable between the iscalimab (91 %) and placebo (96 %) groups.

CONCLUSION

Iscalimab showed favorable safety and improvements compared with placebo in non-thymectomized patients with moderate-to-severe MG. It did not show any protective effect in patients with moderate-to-severe MG.

The impact of vestibular dysfunction on falls and postural instability in individuals with type 2 diabetes with and without diabetic polyneuropathy

Aim

This study aimed to determine the association between vestibular dysfunction, falls, and postural instability in individuals with type 2 diabetes (T2D) compared to healthy control individuals and to examine the impact of diabetic polyneuropathy (DPN).

Methods

This cross-sectional study included individuals with T2D with DPN (n = 43), without DPN (n = 32), and healthy controls (n = 32). Cervical and ocular vestibular evoked myogenic potentials (VEMP) were recorded, and latencies and amplitudes were determined. DPN was diagnosed based on nerve conduction studies and clinical scores. Postural instability was examined using a static posturographic balance system and calculated as an instability index (ST). Falls were recorded retrospectively during the past year. Group comparisons were conducted by using univariate and bivariate statistics.

Results

Individuals with T2D experienced more falls than healthy controls (T2D with DPN n = 12[38%], T2D without DPN n = 15[35%], controls n = 5[16%], p = 0.04). Individuals with T2D had decreased postural stability, T2D with DPN, ST (median of 52[iqi = 33; 77]), T2D without DPN, ST (median of 31[iqi = 24; 39]), controls ST (median of 26[iqi = 19; 33], p = 0.01), when comparing all three groups. Individuals with T2D had a greater number of no-responses in oVEMP compared to controls (T2D with DPN, n = 15[46.9%] T2D without DPN n = 25[58.1%], controls n = 9[28.1%], p = 0.04). No difference was found in cVEMP and oVEMP amplitudes in any of the groups. Irrespectively of DPN, fallers with T2D had decreased oVEMP and cVEMP latencies on the right ears, when comparing to non-fallers, respectively, n10 (fallers [median of 16, iqi=15;19 ms.] vs. non-fallers [median of 25 iqi=16;35 ms]); p13 (fallers [median of 16, iqi=15;17 ms.] vs. non-fallers [median of 15, iqi=8;16 ms.], p < 0.05).

Conclusion

Falls and postural instability were more frequent in individuals with T2D compared to healthy controls. Fallers with T2D had vestibular end-organ impairments based on the oVEMP and cVEMP latencies on the right but not the left ears, irrespective of DPN. Individuals with T2D had more frequent no-response of the oVEMP, indicating impaired vestibular nerve function.

Prevalence and detection rate of major congenital heart disease in twin pregnancies in Denmark

OBJECTIVE

To investigate the national prevalence and prenatal detection rate (DR) of major congenital heart disease (mCHD) in twin pregnancies without twin-to-twin transfusion syndrome (TTTS)-associated CHD in a Danish population following a standardized prenatal screening program.

METHODS

This was a national registry-based study of data collected prospectively over a 10-year period. In Denmark, all women with a twin pregnancy are offered standardized screening and surveillance programs in addition to first- and second-trimester screening for aneuploidies and malformation, respectively: monochorionic (MC) twins every 2 weeks from gestational week 15 and dichorionic (DC) twins every 4 weeks from week 18. The data were retrieved from the Danish Fetal Medicine Database and included all twin pregnancies from 2009-2018, in which at least one fetus had a pre- and/or postnatal mCHD diagnosis. mCHD was defined as CHD requiring surgery within the first year of life, excluding ventricular septal defects. All pregnancy data were pre- and postnatally validated in the local patient files at the four tertiary centers covering the entire country.

RESULTS

A total of 60 cases from 59 twin pregnancies were included. The prevalence of mCHD was 4.6 (95% CI, 3.5-6.0) per 1000 twin pregnancies (1.9 (95% CI, 1.3-2.5) per 1000 live births). The prevalences for DC and MC were 3.6 (95% CI, 2.6-5.0) and 9.2 (95% CI, 5.8-13.7) per 1000 twin pregnancies, respectively. The national prenatal DR of mCHD in twin pregnancies for the entire period was 68.3%. The highest DRs were in cases with univentricular hearts (100%) and the lowest with aortopulmonary window, total anomalous pulmonary venous return, Ebstein's anomaly, aortic valve stenosis and coarctation of the aorta (0-25%). Mothers of children with prenatally undetected mCHD had a significantly higher body mass index (BMI) compared to mothers of children with a prenatally detected mCHD (median, 27 kg/m2 and 23 kg/m2 , respectively; P = 0.02).

CONCLUSIONS

The prevalence of mCHD in twins was 4.6 per 1000 pregnancies and was higher in MC than DC pregnancies. The prenatal DR of mCHD in twin pregnancies was 68.3%. Maternal BMI was higher in cases of prenatally undetected mCHD. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Hospital-diagnosed morbidities and recent surgery as risk factors for developing Guillain-Barré syndrome

BACKGROUND AND PURPOSE

This study was undertaken to determine the association of hospital-diagnosed morbidity and recent surgery with risk of subsequent Guillain-Barré syndrome (GBS) development.

METHODS

We conducted a nationwide population-based case-control study of all patients with first-time hospital-diagnosed GBS in Denmark between 2004 and 2016 and 10 age-, sex-, and index date-matched population controls per case. Hospital-diagnosed morbidities included in the Charlson Comorbidity Index were assessed as GBS risk factors up to 10 years prior to the GBS index date. Incident major surgery was assessed within 5 months prior.

RESULTS

In the 13-year study period, there were 1086 incident GBS cases, whom we compared with 10,747 matched controls. Any pre-existing hospital-diagnosed morbidity was observed in 27.5% of GBS cases and 20.0% of matched controls, yielding an overall matched odds ratio (OR) of 1.6 (95% confidence interval [CI] = 1.4-1.9). The strongest associations were found for leukemia, lymphoma, diabetes, liver disease, myocardial infarction, congestive heart failure, and cerebrovascular disease, with 1.6- to 4.6-fold increased risks of subsequent GBS. GBS risk was strongest for morbidities newly diagnosed during the past 5 months (OR = 4.1, 95% CI = 3.0-5.6). Surgical procedures within 5 months prior were observed in 10.6% of cases and 5.1% of controls, resulting in a GBS OR of 2.2 (95% CI = 1.8-2.7). Risk of developing GBS was highest during the first month following surgery (OR = 3.7, 95% CI = 2.6-5.2).

CONCLUSIONS

In this large nationwide study, individuals with hospital-diagnosed morbidity and recent surgery had a considerably increased risk of GBS.

Changes in axonal and clinical function during intravenous and subcutaneous immunoglobulin therapy in chronic inflammatory demyelinating polyneuropathy

BACKGROUND AND AIMS

Intravenous immunoglobulin (IVIg) has a rapid clinical effect which cannot be explained by remyelination during each treatment cycle in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). This study aimed to investigate axonal membrane properties during the IVIg treatment cycle and their potential correlation with clinically relevant functional measurements.

METHODS

Motor nerve excitability testing (NET) of the median nerve was performed before and 4 and 18 days after initiation of an IVIg treatment cycle in 13 treatment-naïve (early) CIDP patients and 24 CIDP patients with long term (late) IVIg treatment, 12 CIDP patients treated with subcutaneous immunoglobulin (SCIg) and 55 healthy controls. Clinical function was measured extensively using the Six Spot Step test, 10-Meter Walk test, 9-Hole Peg test, grip strength, MRC sum score, Overall Neuropathy Limitations Score and Patient Global Impression of Change.

RESULTS

Superexcitability and S2 accommodation decreased significantly in the early treatment group from baseline to day 4 and returned to baseline levels at day 18, suggesting temporary depolarization of the axonal membrane. A similar trend was observed for the late IVIg group. Substantial clinical improvement was observed in both early and late IVIg groups during the entire treatment cycle. No statistically significant correlation was found between clinical and NET changes. No change was found in NET or clinical function in the SCIg group or controls.

INTERPRETATION

NET suggested temporary depolarization of the axonal membrane during IVIg treatment in treatment naïve CIDP patients. The relation to clinical improvement, however, remains speculative.

Hyaluronidase-facilitated subcutaneous immunoglobulin 10% as maintenance therapy for chronic inflammatory demyelinating polyradiculoneuropathy: The ADVANCE-CIDP 1 randomized controlled trial

BACKGROUND AND AIMS

ADVANCE-CIDP 1 evaluated facilitated subcutaneous immunoglobulin (fSCIG; human immunoglobulin G 10% with recombinant human hyaluronidase) efficacy and safety in preventing chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) relapse.

METHODS

ADVANCE-CIDP 1 was a phase 3, double-blind, placebo-controlled trial conducted at 54 sites in 21 countries. Eligible adults had definite or probable CIDP and adjusted Inflammatory Neuropathy Cause and Treatment (INCAT) disability scores of 0-7 (inclusive), and received stable intravenous immunoglobulin (IVIG) for ≥12 weeks before screening. After stopping IVIG, patients were randomized 1:1 to fSCIG 10% or placebo for 6 months or until relapse/discontinuation. fSCIG 10% was administered at the same dose (or matching placebo volume) and interval as pre-randomization IVIG. The primary outcome was patient proportion experiencing CIDP relapse (≥1-point increase in adjusted INCAT score from pre-subcutaneous treatment baseline) in the modified intention-to-treat population. Secondary outcomes included time to relapse and safety endpoints.

RESULTS

Overall, 132 patients (mean age 54.4 years, 56.1% male) received fSCIG 10% (n = 62) or placebo (n = 70). CIDP relapse was reduced with fSCIG 10% versus placebo (n = 6 [9.7%; 95% confidence interval 4.5%, 19.6%] vs n = 22 [31.4%; 21.8%, 43.0%], respectively; absolute difference: -21.8% [-34.5%, -7.9%], p = .0045). Relapse probability was higher with placebo versus fSCIG 10% over time (p = .002). Adverse events (AEs) were more frequent with fSCIG 10% (79.0% of patients) than placebo (57.1%), but severe (1.6% vs 8.6%) and serious AEs (3.2% vs 7.1%) were less common.

INTERPRETATION

fSCIG 10% more effectively prevented CIDP relapse than placebo, supporting its potential use as maintenance CIDP treatment.

Reduced 3-year risk of hospital admission and mortality after 12-week resistance training of cirrhosis patients: A follow-up of a randomized clinical trial

BACKGROUND AND AIM

Physical activity confers health benefits in many diseases but remains almost unstudied for cirrhosis. We investigated whether a period of resistance training affects the subsequent long-term risk of hospitalization or mortality among patients with cirrhosis.

METHODS

The study includes 39 participants with cirrhosis Child-Pugh class A/B who participated in a prior clinical trial randomized to either resistance training three times per week for 12 weeks or a control group. We gathered data through medical records from trial entry and the following 3 years. The outcomes were time to first hospitalization and all-cause mortality. We used regression models to examine the associations between trial groups and outcomes, adjusting for Child-Pugh class, age, gender, and comorbidity.

RESULTS

Nine patients who trained and 15 controls were hospitalized, resulting in a lower risk of first hospitalization in the training group (adjusted subdistribution hazard ratio of 0.40, 95% confidence interval [CI] [0.17, 0.92]; P = 0.03). One patient who trained and six controls died, resulting in a lower all-cause mortality in the training group (adjusted hazard ratio of 0.06, 95% CI [0.01, 0.66]; P = 0.02).

CONCLUSION

Twelve weeks of resistance training was associated with a reduced risk of first hospitalization and mortality among patients with cirrhosis Child-Pugh class A/B 3 years after trial entry. The mechanisms of this effect are not identified, and larger studies are warranted.

Muscle velocity recovery cycles in myopathy

OBJECTIVE

To understand the pathophysiology of myopathies by using muscle velocity recovery cycles (MVRC) and frequency ramp (RAMP) methodologies.

METHODS

42 patients with quantitative electromyography (qEMG) and biopsy or genetic verified myopathy and 42 healthy controls were examined with qEMG, MVRC and RAMP, all recorded from the anterior tibial muscle.

RESULTS

There were significant differences in the motor unit potential (MUP) duration, the early and late supernormalities of the MVRC and the RAMP latencies in myopathy patients compared to controls (p < 0.05 apart from muscle relatively refractory period (MRRP)). When dividing into subgroups, the above-mentioned changes in MVRC and RAMP parameters were increased for the patients with non-inflammatory myopathy, while there were no significant changes in the group of patients with inflammatory myopathy.

CONCLUSIONS

The MVRC and RAMP parameters can discriminate between healthy controls and myopathy patients, more significantly for non-inflammatory myopathy. MVRC differences with normal MRRP in myopathy differs from other conditions with membrane depolarisation.

SIGNIFICANCE

MVCR and RAMP may have a potential in understanding disease pathophysiology in myopathies. The pathogenesis in non-inflammatory myopathy does not seem to be caused by a depolarisation of the resting membrane potential but rather by the change in sodium channels of the muscle membrane.

The Prevalence of Polyneuropathy in Type 2 Diabetes Subgroups Based on HOMA2 Indices of β-Cell Function and Insulin Sensitivity

OBJECTIVE

Metabolic syndrome components may cumulatively increase the risk of diabetic polyneuropathy (DPN) in type 2 diabetes mellitus (T2DM) patients, driven by insulin resistance and hyperinsulinemia. We investigated the prevalence of DPN in three T2DM subgroups based on indices of β-cell function and insulin sensitivity.

RESEARCH DESIGN AND METHODS

We estimated β-cell function (HOMA2-B) and insulin sensitivity (HOMA2-S) in 4,388 Danish patients with newly diagnosed T2DM. Patients were categorized into subgroups of hyperinsulinemic (high HOMA2-B, low HOMA2-S), classical (low HOMA2-B, low HOMA2-S), and insulinopenic (low HOMA2-B, high HOMA2-S) T2DM. After a median follow-up of 3 years, patients filled the Michigan Neuropathy Screening Instrument questionnaire (MNSIq) to identify DPN (score ≥ 4). We used Poisson regression to calculate adjusted prevalence ratios (PRs) for DPN, and spline models to examine the association with HOMA2-B and HOMA2-S.

RESULTS

A total of 3,397 (77%) patients filled in the MNSIq. The prevalence of DPN was 23% among hyperinsulinemic, 16% among classical, and 14% among insulinopenic patients. After adjusting for demographics, diabetes duration and therapy, lifestyle behaviors, and metabolic syndrome components (waist circumference, triglycerides, HDL cholesterol, hypertension, and HbA1c), the PR of DPN was 1.35 (95% CI 1.15-1.57) for the hyperinsulinemic compared with the classical patients. In spline analyses, we observed a linear relation of higher DPN prevalence with increasing HOMA2-B, independent of both metabolic syndrome components and HOMA2-S.

CONCLUSIONS

Hyperinsulinemia marked by high HOMA2-B is likely an important risk factor for DPN beyond metabolic syndrome components and insulin resistance. This should be considered when developing interventions to prevent DPN.

CSF Findings in Relation to Clinical Characteristics, Subtype, and Disease Course in Patients With Guillain-Barré Syndrome

BACKGROUND AND OBJECTIVES

To investigate CSF findings in relation to clinical and electrodiagnostic subtypes, severity, and outcome of Guillain-Barré syndrome (GBS) based on 1,500 patients in the International GBS Outcome Study.

METHODS

Albuminocytologic dissociation (ACD) was defined as an increased protein level (>0.45 g/L) in the absence of elevated white cell count (<50 cells/μL). We excluded 124 (8%) patients because of other diagnoses, protocol violation, or insufficient data. The CSF was examined in 1,231 patients (89%).

RESULTS

In 846 (70%) patients, CSF examination showed ACD, which increased with time from weakness onset: ≤4 days 57%, >4 days 84%. High CSF protein levels were associated with a demyelinating subtype, proximal or global muscle weakness, and a reduced likelihood of being able to run at week 2 (odds ratio [OR] 0.42, 95% CI 0.25-0.70; p = 0.001) and week 4 (OR 0.44, 95% CI 0.27-0.72; p = 0.001). Patients with the Miller Fisher syndrome, distal predominant weakness, and normal or equivocal nerve conduction studies were more likely to have lower CSF protein levels. CSF cell count was <5 cells/μL in 1,005 patients (83%), 5-49 cells/μL in 200 patients (16%), and ≥50 cells/μL in 13 patients (1%).

DISCUSSION

ACD is a common finding in GBS, but normal protein levels do not exclude this diagnosis. High CSF protein level is associated with an early severe disease course and a demyelinating subtype. Elevated CSF cell count, rarely ≥50 cells/μL, is compatible with GBS after a thorough exclusion of alternative diagnoses.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that CSF ACD (defined by the Brighton Collaboration) is common in patients with GBS.

Myopathy as a cause of Long COVID fatigue: Evidence from quantitative and single fiber EMG and muscle histopathology

OBJECTIVE

To describe neurophysiological abnormalities in Long COVID and correlate quantitative electromyography (qEMG) and single fiber EMG (sfEMG) results to clinical scores and histopathology.

METHODS

84 patients with non-improving musculoskeletal Long COVID symptoms were examined with qEMG and sfEMG. Muscle biopsies were taken in a subgroup.

RESULTS

Mean motor unit potential (MUP) duration was decreased in ≥ 1 muscles in 52 % of the patients. Mean jitter was increased in 17 % of the patients in tibialis anterior and 25 % in extensor digitorum communis. Increased jitter was seen with or without myopathic qEMG. Low quality of life score correlated with higher jitter values but not with qEMG measures. In addition to our previously published mitochondrial changes, inflammation, and capillary injury, we show now in muscle biopsies damage of terminal nerves and motor endplate with abundant basal lamina material. At the endplate, axons were present but no vesicle containing terminals. The post-synaptic cleft in areas appeared atrophic with short clefts and coarse crests.

CONCLUSIONS

Myopathic changes are common in Long COVID. sfEMG abnormality is less common but may correlate with clinical scores. sfEMG changes may be due to motor endplate pathology.

SIGNIFICANCE

These findings may indicate a muscle pathophysiology behind fatigue in Long COVID.

Increased risk of depression after Guillain-Barré syndrome

INTRODUCTION/AIMS

Guillain-Barré syndrome (GBS) is a potentially life-threatening disorder, and some patients may develop subsequent depression related to traumatic stress or permanent loss of motor function. We determined the short-term (0-2 year) and long-term (> 2 year) risk of depression following GBS.

METHODS

Individual-level data from nationwide registries were linked in this population-based cohort study of all first-time hospital-diagnosed GBS patients in Denmark between 2005 and 2016 and individuals from the general population. After exclusion of individuals with prior depression, we computed cumulative rates of depression, defined as either antidepressant drug prescription or depression hospital diagnosis. We used Cox regression analyses to calculate adjusted depression hazard ratios (HRs) following GBS.

RESULTS

We identified 853 incident GBS patients and recruited 8,639 individuals from the general population. Depression within 2 years was observed in 21.3% (95% CI, 18.2-25.0%) of GBS patients and in 3.3% (95% CI, 2.9-3.7%) of general population members, resulting in a hazard ratio (HR) of 7.6 (95% CI, 6.2-9.3). The highest depression HR was observed within the first 3 months after GBS (HR, 20.5; 95% CI, 13.6-30.9). After the first two years, GBS patients and the general population members had similar long-term depression risks with a HR of 0.8 (95% CI, 0.6-1.2).

DISCUSSION

During the first 2 years after GBS hospital admission, patients with GBS have a 7.6-fold increased hazard of depression compared with individuals in the general population. Two years after GBS, the risk of depression is similar to the background population. This article is protected by copyright. All rights reserved.

Standardized Tapering off Subcutaneous Immunoglobulin in Chronic Inflammatory Demyelinating Polyneuropathy

BACKGROUND

Attempting discontinuation of treatment in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) is recommended. However, there is no evidence based regimen for tapering off subcutaneous immunoglobulin (SCIG). This trial investigated stepwise tapering off SCIG to detect remission and the lowest effective dosage. During tapering off, frequent vs less frequent clinical evaluation was compared.

METHODS

Patients with CIDP receiving a stable SCIG dosage followed a standardized tapering off regimen: 90%, 75%, 50%, 25% and 0% of the initial dose every 12th week, pending no deterioration occurred. In case of relapse during tapering off, the lowest effective dose was identified. Treatment with SCIG was registered for two years after participation. Disability score and grip strength were primary parameters. Participants were randomized to clinical evaluation every 6th week (frequent) or 12th week (less frequent).

RESULTS

Fifty-five patients were included of which thirty-five relapsed. Twenty patients (36%) were able to discontinue treatment without relapse. In relapsing patients, median dosage could be reduced by 10% (range, 0-75). After two years, 18 of 20 patients were still in remission without treatment. Frequent clinical evaluation did not detect deterioration more frequently than less frequent evaluation; RR 0.5 (95% CI, 0.2-1.2) (p = 0.17).

CONCLUSION

In stable CIDP patients, SCIG could be completely tapered off in 36% of the patients and only in 10% of these patients relapse occurred during the following two years. More frequent evaluation was not superior to detect deterioration.

Guillain-Barré syndrome following influenza vaccination: A 15-year nationwide population-based case-control study

BACKGROUND AND PURPOSE

Influenza vaccination may increase the risk of developing Guillain-Barré syndrome (GBS) due to an elicited immune response, but the exact magnitude and duration of risk is unclear and hence the aim of this study.

METHODS

We conducted a retrospective nationwide population-based case-control study of prospectively collected data on all patients with first-time hospital-diagnosed GBS in Denmark between 2002 and 2016 and 10 age-, sex- and index date-matched population controls per case. The primary exposure was incident influenza vaccination 1 month prior to admission with GBS. We used medical registries to ascertain a complete hospital contact history of pre-existing morbidities. To examine duration of GBS risk, we repeated the analysis for five consecutive 1-month risk periods following vaccination.

RESULTS

Of the 1295 GBS cases and 12,814 controls, 20 cases (1.5%) and 119 controls (0.9%) had received an influenza vaccination within the last month, yielding a comorbidity-adjusted odds ratio of 1.9 (95% confidence interval 1.1-3.2) for GBS. Stratified analyses by calendar time, gender and age showed similar results. The increased risk of GBS was largely confined to 1 month following influenza vaccination. The population-attributable fraction of GBS from influenza vaccination in Denmark was 0.4%.

CONCLUSIONS

Influenza vaccination was associated with a slightly elevated risk of GBS occurrence within 1 month after vaccination. However, only 1.5% of GBS cases in Denmark are associated with recent influenza vaccination. Thus, the benefit of influenza vaccines in preventing influenza infections and associated morbidity and mortality needs to be weighed against the small absolute risk of GBS.

Towards prevention of diabetic peripheral neuropathy: clinical presentation, pathogenesis, and new treatments

Diabetic peripheral neuropathy (DPN) occurs in up to half of individuals with type 1 or type 2 diabetes. DPN results from the distal-to-proximal loss of peripheral nerve function, leading to physical disability and sometimes pain, with the consequent lowering of quality of life. Early diagnosis improves clinical outcomes, but many patients still develop neuropathy. Hyperglycaemia is a risk factor and glycaemic control prevents DPN development in type 1 diabetes. However, glycaemic control has modest or no benefit in individuals with type 2 diabetes, probably because they usually have comorbidities. Among them, the metabolic syndrome is a major risk factor for DPN. The pathophysiology of DPN is complex, but mechanisms converge on a unifying theme of bioenergetic failure in the peripheral nerves due to their unique anatomy. Current clinical management focuses on controlling diabetes, the metabolic syndrome, and pain, but remains suboptimal for most patients. Thus, research is ongoing to improve early diagnosis and prognosis, to identify molecular mechanisms that could lead to therapeutic targets, and to investigate lifestyle interventions to improve clinical outcomes.

An International Perspective on Preceding Infections in Guillain-Barré Syndrome: The IGOS-1000 Cohort

BACKGROUND AND OBJECTIVES

Infections play a key role in the development of Guillain-Barré syndrome (GBS) and have been associated with specific clinical features and disease severity. The clinical variation of GBS across geographical regions has been suggested to be related to differences in the distribution of preceding infections, but this has not been studied on a large scale.

METHODS

We analyzed the first 1,000 patients included in the International GBS Outcome Study with available biosamples (n = 768) for the presence of a recent infection with Campylobacter jejuni, hepatitis E virus, Mycoplasma pneumoniae, cytomegalovirus, and Epstein-Barr virus.

RESULTS

Serologic evidence of a recent infection with C. jejuni was found in 228 (30%), M. pneumoniae in 77 (10%), hepatitis E virus in 23 (3%), cytomegalovirus in 30 (4%), and Epstein-Barr virus in 7 (1%) patients. Evidence of more than 1 recent infection was found in 49 (6%) of these patients. Symptoms of antecedent infections were reported in 556 patients (72%), and this proportion did not significantly differ between those testing positive or negative for a recent infection. The proportions of infections were similar across continents. The sensorimotor variant and the demyelinating electrophysiologic subtype were most frequent across all infection groups, although proportions were significantly higher in patients with a cytomegalovirus and significantly lower in those with a C. jejuni infection. C. jejuni-positive patients were more severely affected, indicated by a lower Medical Research Council sum score at nadir (p = 0.004) and a longer time to regain the ability to walk independently (p = 0.005). The pure motor variant and axonal electrophysiologic subtype were more frequent in Asian compared with American or European C. jejuni-positive patients (p < 0.001, resp. p = 0.001). Time to nadir was longer in the cytomegalovirus-positive patients (p = 0.004).

DISCUSSION

Across geographical regions, the distribution of infections was similar, but the association between infection and clinical phenotype differed. A mismatch between symptom reporting and serologic results and the high frequency of coinfections demonstrate the importance of broad serologic testing in identifying the most likely infectious trigger. The association between infections and outcome indicates their value for future prognostic models.

Myopathy as a cause of fatigue in long-term post-COVID-19 symptoms: Evidence of skeletal muscle histopathology

Background and purpose

Among post‐COVID‐19 symptoms, fatigue is reported as one of the most common, even after mild acute infection, and as the cause of fatigue, myopathy diagnosed by electromyography has been proposed in previous reports. This study aimed to explore the histopathological changes in patients with post‐COVID‐19 fatigue.

Methods

Sixteen patients (mean age = 46 years) with post‐COVID‐19 complaints of fatigue, myalgia, or weakness persisting for up to 14 months were included. In all patients, quantitative electromyography and muscle biopsies analyzed with light and electron microscopy were taken.

Results

Muscle weakness was present in 50% and myopathic electromyography in 75%, and in all patients there were histological changes. Muscle fiber atrophy was found in 38%, and 56% showed indications of fiber regeneration. Mitochondrial changes, comprising loss of cytochrome c oxidase activity, subsarcollemmal accumulation, and/or abnormal cristae, were present in 62%. Inflammation was found in 62%, seen as T lymphocytes and/or muscle fiber human leukocyte antigen ABC expression. In 75%, capillaries were affected, involving basal lamina and cells. In two patients, uncommon amounts of basal lamina were found, not only surrounding muscle fibers but also around nerves and capillaries.

Conclusions

The wide variety of histological changes in this study suggests that skeletal muscles may be a major target of SARS‐CoV‐2, causing muscular post‐COVID‐19 symptoms. The mitochondrial changes, inflammation, and capillary injury in muscle biopsies can cause fatigue in part due to reduced energy supply. Because most patients had mild–moderate acute affection, the new variants that might cause less severe acute disease could still have the ability to cause long‐term myopathy.

Effects of progressive resistance training in individuals with type 2 diabetic polyneuropathy: a randomised assessor-blinded controlled trial

AIMS/HYPOTHESIS

The aim of this study was to evaluate the effects of progressive resistance training (PRT) on muscle strength, intraepidermal nerve fibre density (IENFD) and motor function in individuals with type 2 diabetic polyneuropathy (DPN) and to compare potential adaptations to those of individuals with type 2 diabetes without DPN and healthy controls.

METHODS

This was an assessor-blinded trial conducted at the Neurology department, Aarhus University Hospital. Adults with type 2 diabetes, with and without DPN and healthy control participants were randomised to either supervised PRT or non-PRT for 12 weeks. Allocation was concealed by a central office unrelated to the study. The co-primary outcomes were muscle strength in terms of the peak torque of the knee and ankle extensors and flexors, and IENFD. Secondary outcome measures included the 6 min walk test (6MWT), five-time sit-to-stand test (FTSST) and postural stability index obtained by static posturography.

RESULTS

A total of 109 individuals were enrolled in three groups (type 2 diabetes with DPN [n = 42], type 2 diabetes without DPN [n = 32] and healthy control [n = 35]). PRT resulted in muscle strength gains of the knee extensors and flexors in all three groups using comparative analysis (DPN group, PRT 10.3 ± 9.6 Nm vs non-PRT -0.4 ± 8.2 Nm; non-DPN group, PRT 7.5 ± 5.8 Nm vs non-PRT 0.6 ± 8.8 Nm; healthy control group, PRT 6.3 ± 9.0 Nm vs non-PRT -0.4 ± 8.4 Nm; p<0.05, respectively). Following PRT the DPN group improved the 6MWT (PRT 34.6 ± 40.9 m vs non-PRT 2.7 ± 19.6 m; p=0.001) and the FTSST (PRT -1.5 ± 2.2 s vs non-PRT 1.5 ± 4.6 s; p=0.02). There was no change in IENFD following PRT in any of the groups.

CONCLUSIONS/INTERPRETATION

PRT improved muscle strength of the knee extensors and flexors and motor function in individuals with type 2 diabetic polyneuropathy at levels comparable with those seen in individuals with diabetes without DPN and healthy control individuals, while no effects were observed in IENFD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03252132 FUNDING: Research reported in this paper is part of the International Diabetic Neuropathy Consortium (IDNC) research programme, supported by a Novo Nordisk Foundation Challenge Program grant (grant no. NNF14OC0011633) and Aarhus University.

Association Between Incident Cancer and Guillain-Barré Syndrome Development: A Nationwide Case-Control Study

BACKGROUND AND OBJECTIVES

Cancer may increase the risk of developing Guillain-Barré syndrome (GBS) due to molecular mimicry or immunosuppression, but the exact relationship is unclear. We aimed to determine the association between incident cancer and the following risk of GBS development.

METHODS

We conducted a nationwide population-based case-control study of all patients with first-time hospital-diagnosed GBS in Denmark between 1987 and 2016 and 10 age, sex and index date-matched population controls per case. We identified incident cancer diagnoses between six months prior to and two months after the GBS index date. We used conditional logistic regression to compute ORs as a measure of relative risk and performed stratified analyses to assess the impact of cancer on GBS risk in strata of calendar-periods, sex and age. In sensitivity analyses, to assess any potential risk of survival bias induced by including cancer diagnoses potentially made after GBS diagnosis, we examined incident cancers in both a broader exposure window (one year before to three months after GBS index date) and a narrower window (six months to one month before the GBS index date).

RESULTS

Of the 2,414 patients with GBS and 23,909 controls included, 49 cases (2.0%) and 138 controls (0.6%) had a recent cancer diagnosis, respectively, yielding a matched odds ratio (OR) of 3.6 (95% confidence interval (CI), 2.6- 5.1) for GBS associated with cancer. Stratification by calendar time, gender and age showed robust results for the association between cancer and GBS, with no major variations. Broadening and narrowing the exposure window produced slightly weakened associations of OR, 2.4 (95% CI, 1.8-3.3) and OR, 2.5 (95% CI, 1.5-4.1), respectively. The GBS ORs were highest for cancers of the lymphatic and hematopoietic tissue (OR, 7.2; 95% CI, 2.9-18.0), respiratory tract (OR, 5.6; 95% CI, 2.7-11.9), prostate and other male genital organ (OR, 5.0; 95% CI, 2.1-11.6) and breast cancer (OR, 5.0; 95% CI, 1.7-14.5).

DISCUSSION

In this large nationwide epidemiologic study, incident cancer was associated with a markedly increased risk of subsequent GBS development. The results suggest that yet unidentified factors present in several types of cancer drive this association.

The Impact of Diabetic Neuropathy on Activities of Daily Living, Postural Balance and Risk of Falls - A Systematic Review

OBJECTIVE

The objective of this review is to discuss a compilation of the currently available literature regarding the impact of diabetic neuropathy (DN) on activities of daily living (ADL), postural stability, and risk of falls.

METHODS

A systematic electronic search strategy was conducted on PubMed/MEDLINE database, Cochrane Library, and Embase in March 2020. This narrative review included clinical cross-sectional studies assessing ADL, postural balance, and falls in adults with DN. All studies underwent a quality assessment based on the Newcastle Ottawa scale developed to assess cross-sectional studies.

RESULTS

Forty-two studies were identified. A total of 37 studies evaluated postural stability in DN, 10 studies assessed fall accidents, and three studies assessed ADL in individuals with DN. Seven studies assessed both postural stability and fall accidents, and one study assessed postural stability and ADL. Each of the studied outcome variables was assessed separately. Based on a quality assessment, eight studies were excluded resulting in an evaluation of 34 studies.

CONCLUSIONS

Diabetic neuropathy has a negative impact on postural balance and gait kinematics combined with an increased fall risk. Because of the few number of studies available, we were unable to evaluate the impact of DN on ADL. Our findings are in concordance with previous reviews, supporting the evidence for DN as a critical measure negatively impacting postural stability and fall risk in individuals with diabetes. Further clinical investigative studies are needed.

Increased mortality following Guillain-Barré syndrome: A population-based cohort study

BACKGROUND AND PURPOSE

Guillain-Barré syndrome (GBS) may be fatal in the acute phase but also affect long-term prognosis due to irreversible sequelae and secondary medical complications. We determined the short-term, intermediate, and long-term mortality of GBS compared to the general population.

METHODS

Individual-level data from nationwide registries were linked in this matched cohort study of all first-time hospital-diagnosed GBS patients in Denmark between 1987 and 2016 and 10 individuals from the general population, matched on age, sex, and index date. We used Cox regression analysis to calculate matched mortality hazard ratios (HRs) following GBS, assessing short-term (0-6 months), intermediate (>6 months-4 years), and long-term (>4 years) mortality.

RESULTS

We identified 2414 patients with GBS and 23,909 matched individuals from the general population. Short-term mortality was 4.8% (95% confidence interval [CI] = 4.0-5.8) and 0.8% (95% CI = 0.7-0.9) for GBS patients and general population members, respectively, resulting in an HR of 6.6 (95% CI = 4.0-5.8). Intermediate mortality was 7.6% (95% CI = 6.5-8.9), compared with 5.8% (95% CI = 5.5-6.1) for general population members, corresponding to an HR of 1.5 (95% CI = 1.3-1.8). After the first 4 years, long-term mortality showed similar results for GBS patients and general population members (HR = 1.1, 95% CI = 0.9-1.2).

CONCLUSIONS

During the first 6 months after GBS hospital admission, GBS was associated with a 6.6-fold increased mortality as compared with the background population of the same age. Mortality remained increased for approximately 4 years following GBS, and then leveled off to a similar long-term mortality rate.

Normative reference values for the dorsal sural nerve derived from a large multicenter cohort

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We determined reference values for the dorsal sural nerve from a large cohort, aged 21-80.

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Amplitude and conduction velocity depended on both age and height.

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We provide formulas for reference limits.

Objectives

Dorsal sural nerve conduction studies (NCS) may increase the sensitivity for the diagnosis of polyneuropathy, but clinical use is limited by a lack of reliable normative reference values in all age-groups. The aim of our study was to develop reference values for the dorsal sural nerve, based on a large multicenter cohort of healthy subjects.

Methods

Bilateral antidromic NCS were performed using standard surface electrodes in 229 healthy subjects (aged 21–80 years; median: 54 years). We assessed the normality of data distribution for amplitudes and conduction velocity (CV) and for their logarithmic (ln) transformation. The effects of age and height were determined using linear regression analysis.

Results

Sensory potentials were present in all subjects. Logarithmically transformed data were normally distributed. Age² and height were most significantly associated with amplitude, and age and height with CV, respectively. There was no significant side-difference. Mean amplitudes (right and left) were 4.8 and 4.9 μV and mean CV 46.7 and 46.9 m/s. Reference limits were e ^{(3.712515 – 0.0000956 * age2 – 0.0115883 * height ± 1.96 * 0.51137)} for amplitude and e ^{(4.354374 – 0.0021081 * age – 0.0023354 * height ± 1.96 * 0.11161)} for CV.

Conclusions

Dorsal sural nerve NCS are robust and have well defined normative limits.

Significance

The findings provide a basis for more sensitive NCS in clinical practice and future studies of the diagnostic accuracy of NCS in polyneuropathy.

Falls and fractures associated with type 2 diabetic polyneuropathy: A cross-sectional nationwide questionnaire study

AIMS/INTRODUCTION

To examine the prevalence of falls and fractures, and the association with symptoms of diabetic polyneuropathy (DPN) in patients with recently diagnosed type 2 diabetes.

MATERIALS AND METHODS

A detailed questionnaire on neuropathy symptoms and falls was sent to 6,726 patients enrolled in the Danish Center for Strategic Research in Type 2 Diabetes cohort (median age 65 years, diabetes duration 4.6 years). Complete data on fractures and patient characteristics were ascertained from population-based health registries. We defined possible DPN as a score ≥4 on the Michigan Neuropathy Screening Instruments questionnaire. Using Poisson regression analyses, we estimated the adjusted prevalence ratio (aPR) of falls and fractures, comparing patients with and without DPN.

RESULTS

In total, 5,359 patients (80%) answered the questions on the Michigan Neuropathy Screening Instruments questionnaire and falls. Within the year preceding the questionnaire response, 17% (n = 933) reported at least one fall and 1.4% (n = 76) suffered from a fracture. The prevalence ratio of falls was substantially increased in patients with possible DPN compared with those without (aPR 2.33, 95% confidence interval [CI] 2.06-2.63). The prevalence ratio increased with the number of falls from aPR 1.51 (95% CI 1.22-1.89) for one fall to aPR 5.89 (95% CI 3.84-9.05) for four or more falls within the preceding year. Possible DPN was associated with a slightly although non-significantly increased risk of fractures (aPR 1.32, 95% CI 0.75-2.33).

CONCLUSIONS

Patients with recently diagnosed type 2 diabetes and symptoms of DPN had a highly increased risk of falling. These results emphasize the need for preventive interventions to reduce fall risk among patients with type 2 diabetes and possible DPN.

Uterine torsion in a full-term pregnancy presenting as prolonged latent phase and fetal intolerance of labor: A case report

Background

Uterine torsion is defined as torsion of the uterus around its longitudinal axis exceeding 45 degrees. It is a rare obstetric complication. It is a dangerous complication that can lead to placental abruption and intrauterine fetal death. Although rare, early diagnosis is crucial to expedite intervention and optimize outcomes. While the few cases in the current literature have documented acute presentations of uterine torsion, our case is unique in that it had a slower evolution.

Case

A 38-year-old woman, G2P0, was admitted at 37 weeks 0 days of gestation for induction of labor for gestational diabetes mellitus, pre-eclampsia, and maternal BMI of 60. Due to a prolonged latent phase of labor and fetal intolerance of labor, primary cesarean was recommended. Through a sub-umbilical approach, the uterus was dextro-rotated almost 180 degrees and blanched with engorged uterine vessels. A vertical uterine incision was made, and a asphyxiated female infant was delivered via breech extraction. APGAR scores were 2, 7, and 8. The infant required brief respiratory support following delivery. The postoperative course was uncomplicated, with normal recovery time.

Conclusion

Uterine torsion poses significant risk to both mother and fetus. The phenomenon is so rare that epidemiological data are difficult to gather. In our case, the presentation was gradual compared with the acute presentations that have been reported, which may mislead clinicians toward more benign diagnoses. Our case report aims to add to the literature on uterine torsion, providing a unique presentation, clinical features, and treatment.

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Uterine torsion is torsion of the uterus around its longitudinal axis exceeding 45 degrees.

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It is a rare obstetric complication.

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Severe acute uterine torsion can result in placental abruption, intrauterine fetal death, and maternal death.

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This case of uterine torsion presented as prolonged latent phase and fetal intolerance of labor.

•

Delivery was achieved via classical cesarean section.

Falls in individuals with type 2 diabetes; a cross-sectional study on the impact of motor dysfunction, postural instability and diabetic polyneuropathy

AIM

To estimate the incidence of falls in individuals with type 2 diabetes compared to healthy controls and to describe the characteristics of fallers with type 2 diabetes in relation to motor dysfunction, postural instability and diabetic polyneuropathy (DPN).

METHODS

This is a cross-sectional study of individuals with type 2 diabetes with DPN (n = 54), without DPN (n = 38) and healthy controls (n = 39). Falls were recorded within the preceding year. DPN was defined by clinical scores and nerve conduction studies. Motor function was assessed by a 6-min walk test (6 MWT), five-time sit-to-stand test (FTSST) and isokinetic dynamometry at the non-dominant ankle and knee. An instability index (ST) was measured using static posturography. Univariate and bivariate descriptive statistics were used for group comparisons.

RESULTS

Compared with healthy controls, individuals with diabetes had a higher incidence of falls 36%, (n = 33) versus 15%, (n = 6), p = 0.02. There were no differences in falls when comparing individuals with and without DPN. Fallers had an impaired 6 MWT versus non-fallers (450 ± 153 m vs. 523 ± 97 m respectively), a slower FTSST (11.9 ± 4.2 s vs. 10.3 ± 2.9 s respectively) and a higher ST (53 ± 29 vs. 41 ± 17 respectively), p < 0.02 for all.

CONCLUSION

Individuals with type 2 diabetes reported a higher number of falls within the preceding year compared to healthy controls, irrespective of the presence of DPN. The main factors associated with falls were increased postural instability, lower walking capacity and slower sit-to-stand movements. The 6 MWT, FTSST and posturography should be considered in future screening programs in identification of individuals at risk for falls.

Diabetic Polyneuropathy Early in Type 2 Diabetes Is Associated With Higher Incidence Rate of Cardiovascular Disease: Results From Two Danish Cohort Studies

OBJECTIVE

Symptoms indicative of diabetic polyneuropathy (DPN) early in type 2 diabetes may act as a marker for cardiovascular disease (CVD) and death.

RESEARCH DESIGN AND METHODS

We linked data from two Danish type 2 diabetes cohorts, the Anglo-Danish-Dutch Study of Intensive Treatment in People With Screen-Detected Diabetes in Primary Care (ADDITION-Denmark) and the Danish Centre for Strategic Research in Type 2 Diabetes (DD2), to national health care registers. The Michigan Neuropathy Screening Instrument questionnaire (MNSIq) was completed at diabetes diagnosis in ADDITION-Denmark and at a median of 4.6 years after diagnosis of diabetes in DD2. An MNSIq score ≥4 was considered as indicative of DPN. Using Poisson regressions, we computed incidence rate ratios (IRRs) of CVD and all-cause mortality comparing MNSIq scores ≥4 with scores <4. Analyses were adjusted for a range of established CVD risk factors.

RESULTS

In total, 1,445 (ADDITION-Denmark) and 5,028 (DD2) individuals were included in the study. Compared with MNSIq scores <4, MNSIq scores ≥4 were associated with higher incidence rate of CVD, with IRRs of 1.79 (95% CI 1.38-2.31) in ADDITION-Denmark, 1.57 (CI 1.27-1.94) in the DD2, and a combined IRR of 1.65 (CI 1.41-1.95) in a fixed-effect meta-analysis. MNSIq scores ≥4 did not associate with mortality; combined mortality rate ratio was 1.11 (CI 0.83-1.48).

CONCLUSIONS

The MNSIq may be a tool to identify a subgroup within individuals with newly diagnosed type 2 diabetes with a high incidence rate of subsequent CVD. MNSIq scores ≥4, indicating DPN, were associated with a markedly higher incidence rate of CVD, beyond that conferred by established CVD risk factors.

Overactive bladder in patients with myasthenia gravis-A cross-sectional population-based study

BACKGROUND

In myasthenia gravis (MG), first-line treatment for MG is acetylcholinesterase inhibitors which alleviates symptoms, but concomitantly may cause autonomic adverse effects.

AIMS OF THE STUDY

In this study, we evaluated if symptoms of overactive bladder (OAB) are more frequent among MG patients than healthy controls.

METHODS

Eighty-three MG patients and 50 healthy sex- and age-matched controls were included and answered the questionnaire "International Consultation on Incontinence Questionnaire Overactive Bladder Module" (ICIQ-OAB), including questions about polyuria, nocturia, urgency, and stress incontinence. Clinical severity of MG was determined based on three standardized clinical evaluations.

RESULTS

Compared to control subjects, MG patients had a higher total OAB score (median 5 [range 0-12] versus 3 [0; 7]) (p < 0.005) with higher scores concerning all four items. Also, MG patients had a higher bother score (10 [0-40] versus 5 [0-40]) (p < 0.05). Patients receiving a daily dose of pyridostigmine of more than 300 mg had a higher OAB score than other patients.

CONCLUSIONS

Myasthenia gravis patients have more bothering symptoms of OAB than healthy controls, related to the daily dose of pyridostigmine. To minimize adverse effects in patients with symptoms of OAB, the pyridostigmine dose should be as low as possible.

Oral function in patients with myasthenia gravis

Myasthenia Gravis (MG) is characterised by muscle weakness and increased fatigability. The aim of this pilot study was to investigate if patients with MG demonstrate different functional chewing patterns and report more complaints related to mastication as compared with healthy controls. Twelve patients (median 60 years Q1–Q3: 46–70) with generalised MG and nine healthy controls (median 57 years Q1–Q3: 55–63) participated. All participants underwent dental and oral examination and were asked to fill in a questionnaire concerning oral health. Static maximum bite force was measured with a bite force transducer, electromyography in the masseter, temporalis, and suprahyoid muscles were recorded, and jaw movement was tracked, during a 5-minute gum chewing test. The patients had more oral complaints (oral health impact profile total score 22.6 vs 7.5 P < 0.01) and had lower peak bite force than controls (18.8kgf (11.1;26.4) (95% CI) vs 29.5 kgf (21.6; 37.4) (P = 0.04)). In contrast, fatigability of the masticatory muscles, as defined by number of chewing cycles during the gum-chewing test, did not differ between patients and controls (P = 0.10). In conclusion, patients had more oral complaints and lower bite force than controls, but did not show significantly different functional chewing patterns. Future studies should aim at integrating measurement of peak force into functional tests. Attention should be given to oral complaints of patients with MG.

Gender differences in clinical outcomes in myasthenia gravis: A prospective cohort study

INTRODUCTION/AIMS

It is uncertain whether clinical outcomes differ between male and female patients with myasthenia gravis (MG) while receiving standard clinical care.

METHODS

In a prospective cohort study of 107 patients with MG receiving standard of care from 2012 to 2019, the Quantitative MG (QMG), the MG Composite (MGC), the MG Activities of Daily Living (MG-ADL), and the MG Quality of Life 15-Items (QOL15) were determined. Clinical outcomes were analyzed in relation to gender.

RESULTS

Mean follow-up time was 4.8 (±0.4) y, and 70 patients completed all follow-up assessments. Patients improved on all clinical scores: QMG -1.8 (P < .001), MGC -1.5 (P < .001), MG-ADL -1.3 (P < .001), and QOL15 -3.0 (P < .001). Females improved less than males on the QMG (P = .01), MGC (P < .001), MG-ADL (P = .006), and QOL15 (P < .001) independent of potential confounders. Males had moderate to strong correlations between changes in all clinical scales (r range 0.52 to 0.73), whereas females had weak correlations between changes in the QMG and MG-ADL (r = 0.13), the QMG and QOL15 (r = 0.27), the MGC and MG-ADL (r = 0.21), the MGC and QOL15 (r = 0.00), and the MG-ADL and QOL15 (r = 0.31).

DISCUSSION

Females improved less compared to males on objective and patient-reported outcomes. Moreover, females improved more on objective measures than on patient-reported outcomes. These gender differences should receive attention in clinical care and in the design of future trials.

Myopathic changes in patients with long-term fatigue after COVID-19

Objective

To investigate the peripheral nerve and muscle function electrophysiologically in patients with persistent neuromuscular symptoms following Coronavirus disease 2019 (COVID-19).

Methods

Twenty consecutive patients from a Long-term COVID-19 Clinic referred to electrophysiological examination with the suspicion of mono- or polyneuropathy were included. Examinations were performed from 77 to 255 (median: 216) days after acute COVID-19. None of the patients had received treatment at the intensive care unit. Of these, 10 patients were not even hospitalized. Conventional nerve conduction studies (NCS) and quantitative electromyography (qEMG) findings from three muscles were compared with 20 age- and sex-matched healthy controls.

Results

qEMG showed myopathic changes in one or more muscles in 11 patients (55%). Motor unit potential duration was shorter in patients compared to healthy controls in biceps brachii (10.02 ± 0.28 vs 11.75 ± 0.21), vastus medialis (10.86 ± 0.37 vs 12.52 ± 0.19) and anterior tibial (11.76 ± 0.31 vs 13.26 ± 0.21) muscles. All patients with myopathic qEMG reported about physical fatigue and 8 patients about myalgia while 3 patients without myopathic changes complained about physical fatigue.

Conclusions

Long-term COVID-19 does not cause large fibre neuropathy, but myopathic changes are seen.

Significance

Myopathy may be an important cause of physical fatigue in long-term COVID-19 even in non-hospitalized patients.

Function, structure and quality of striated muscles in the lower extremities in patients with late onset Pompe Disease-an MRI study

Background

Pompe Disease (PD) is a rare inherited metabolic myopathy, caused by lysosomal-α-glucosidase (GAA) deficiency, which leads to glycogen accumulation within the lysosomes, resulting in cellular and tissue damage. Due to the emergence of a disease modifying treatment with recombinant GAA there has been a large increase in studies of late onset Pompe Disease (LOPD) during the last decade.

Methods

The present study evaluates muscle quality in 10 patients with LOPD receiving treatment with enzyme replacement therapy and in 10 age and gender matched healthy controls applying T₁-weighted Dixon MR imaging and isokinetic dynamometry. Muscle quality was determined by muscle strength in relation to muscle size (contractile cross-sectional area, CSA) and to muscle quality (fat fraction). A follow-up evaluation of the patients was performed after 8–12 months. Patient evaluations also included: six-minute walking test (6MWT), forced vital capacity, manual muscle testing and SF-36 questionnaire.

Results

Fat fraction of knee flexors (0.15 vs 0.07, p < 0.05) and hip muscles (0.11 vs 0.07, p < 0.05) were higher in patients than controls. In patients, contractile CSA correlated with muscle strength (knee flexors: r = 0.86, knee extensors: r = 0.88, hip extensors: r = 0.83, p < 0.05). No correlation was found between fat fraction and muscle strength. The fat fraction of thigh muscles did not correlate with scores from the clinical tests nor did it correlate with the 6MWT. During follow-up, the contractile CSA of the knee extensors increased by 2%. No other statistically significant change was observed. Quantitative MRI reflects muscle function in patients with LOPD, but larger long-term studies are needed to evaluate its utility in detecting changes over time.

Sensory and motor axonal excitability testing in early diabetic neuropathy

OBJECTIVE

The aim of the present study was to gain insight into the pathophysiology of diabetic polyneuropathy (DPN) and examine the diagnostic value of sensory and motor axonal excitability testing.

METHODS

One hundred and eleven type 2 diabetics with and without DPN (disease duration: 6.36 ± 0.25 years) and 60 controls were included. All participants received a thorough clinical examination including Michigan Neuropathy Screening Instrument (MNSI) score, nerve conduction studies (NCS), and sensory and motor excitability tests. Patients were compared by the likelihood of neuropathy presence, ranging from no DPN (17), possible/probable DPN (46) to NCS-confirmed DPN (48).

RESULTS

Motor excitability tests showed differences in rheobase and depolarizing threshold electrotonus measures between NCS-confirmed DPN group and controls but no changes in hyperpolarising threshold electrotonus or recovery cycle parameters. Sensory excitability showed even less changes despite pronounced sensory NCS abnormalities. There were only weak correlations between the above motor excitability parameters and clinical scores.

CONCLUSIONS

Changes in excitability in the examined patient group were subtle, perhaps because of the relatively short disease duration.

SIGNIFICANCE

Less pronounced excitability changes than NCS suggest that axonal excitability testing is not of diagnostic value for early DPN and does not provide information on the mechanisms.

Painful and non-painful diabetic neuropathy, diagnostic challenges and implications for future management

Peripheral neuropathy is one of the most common complications of both type 1 and type 2 diabetes. Up to half of patients with diabetes develop neuropathy during the course of their disease, which is accompanied by neuropathic pain in 30-40% of cases. Peripheral nerve injury in diabetes can manifest as progressive distal symmetric polyneuropathy, autonomic neuropathy, radiculo-plexopathies, and mononeuropathies. The most common diabetic neuropathy is distal symmetric polyneuropathy, which we will refer to as DN, with its characteristic glove and stocking like presentation of distal sensory or motor function loss. DN or its painful counterpart, painful DN, are associated with increased mortality and morbidity; thus, early recognition and preventive measures are essential. Nevertheless, it is not easy to diagnose DN or painful DN, particularly in patients with early and mild neuropathy, and there is currently no single established diagnostic gold standard. The most common diagnostic approach in research is a hierarchical system, which combines symptoms, signs, and a series of confirmatory tests. The general lack of long-term prospective studies has limited the evaluation of the sensitivity and specificity of new morphometric and neurophysiological techniques. Thus, the best paradigm for screening DN and painful DN both in research and in clinical practice remains uncertain. Herein, we review the diagnostic challenges from both clinical and research perspectives and their implications for managing patients with DN. There is no established DN treatment, apart from improved glycaemic control, which is more effective in type 1 than in type 2 diabetes, and only symptomatic management is available for painful DN. Currently, less than one-third of patients with painful DN derive sufficient pain relief with existing pharmacotherapies. A more precise and distinct sensory profile from patients with DN and painful DN may help identify responsive patients to one treatment versus another. Detailed sensory profiles will lead to tailored treatment for patient subgroups with painful DN by matching to novel or established DN pathomechanisms and also for improved clinical trials stratification. Large randomized clinical trials are needed to identify the interventions, i.e. pharmacological, physical, cognitive, educational, etc., which lead to the best therapeutic outcomes.

A Search for Undiagnosed Charcot-Marie-Tooth Disease Among Patients Registered with Unspecified Polyneuropathy in the Danish National Patient Registry

Purpose

In a recent study based on data from the Danish National Patients Registry (DNPR), we reported the prevalence of Charcot-Marie-Tooth disease (CMT) in Denmark to be 22.5 per 100.000. This prevalence is most likely a minimum estimate, as many cases of CMT may be misdiagnosed or remain undiagnosed due to the heterogeneous nature of the disorder. The aim of this study was to investigate the possible number of undiagnosed CMT cases among patients registered with unspecified polyneuropathy (UP) diagnoses in the DNPR.

Patients and Methods

From the DNPR we extracted data on all patients given an UP diagnosis in the period 1977 to 2012. We selected all patients diagnosed with a primary UP diagnosis before age 40 at a department of neurology, neurophysiology, clinical genetics or pediatrics, and excluded all patients with a specified polyneuropathy diagnosis or with diagnostic codes related to alcohol and diabetes mellitus. To assess the proportion of possible CMT patients, we performed medical record review in a random sample of patients diagnosed in the Central Denmark Region. To further investigate the possible overlap between UP and CMT in the DNPR, we performed a series of searches for ICD-8 and ICD-10 codes related to CMT.

Results

Between 1977 and 2012, 30.903 patients were diagnosed with UP without also being diagnosed with CMT. A total of 940 patients fulfilled the selection criteria. We found that 21.5% (95% CI 13.1%–32.2%) of the cases in the random sample fulfilled our criteria for CMT. This estimate increases the prevalence of CMT in Denmark with 3.6 per 100,000 (95% CI 2.4%–5.5%).

Conclusion

This study illustrates how hitherto undiagnosed CMT patients may be identified in the DNPR and further reports the number of possible CMT cases. Our results support the hypothesis that the true prevalence of CMT is higher than recently reported.

[Diabetic neuropathy caused by too rapid downregulation of blood glucose]

Treatment-induced neuropathy of diabetes is an iatrogenic acute painful sensory and autonomic neuropathy. The condition is caused by rapid downregulation of blood glucose after a long period of hyperglycaemia. In this case report, a 43-year-old man with Type 1 diabetes and severe metabolic dysregulation had downregulated his blood glucose level with 3.8% over ten weeks through optimised insulin treatment and weight loss. He developed severe neuropathic pain due to small fiber neuropathy and neurogenic autonomic dysfunction with erectile dysfunction, urine retention and cardiovagal and enteric dysfunction.

Isokinetic strength and degeneration of lower extremity muscles in patients with myotonic dystrophy; an MRI study

Our aim was to determine isokinetic strength and degeneration of lower extremity muscles in patients with Myotonic Dystrophy (DM1). In 19 patients with DM1 and 19 matched controls, strength measured by isokinetic dynamometry was expressed as percentage of expected strength (ePct), adjusted for age, height, weight and gender. MRI of the hip, thigh and calf muscles were obtained. Fat fraction (FF), mean contractile cross-sectional area (cCSA) and specific strength (Nm/cm²) were calculated. Patients' ankle plantar flexors, knee flexors and extensors had higher FF (Δ: 0.08 - 0.42) and lower cCSA (Δ: 3.2 -17.1 cm²) compared to controls (p ≤ 0.005). EPct (Δ: 19.5 - 41.6%) and specific strength (Δ: 0.27 - 0.96 Nm/cm²) were lower in the majority of patients muscle groups (p˂0.05). Close correlations were found for patients when relating ePct to; FF for plantar flexors (R²=0.742, p<0.001) and knee extensors (R²=0.732, p<0.001), cCSA for plantar flexors (R²=0.696, p<0.001) and knee extensors (R²=0.633, p<0.001), and specific strength for dorsal flexors (ρ=0.855, p = 0.008). In conclusion, patients had weaker lower extremity muscles with higher FF, lower cCSA and specific strength compared to controls. Muscle degeneration determined by quantitative MRI strongly correlated to strength supporting its feasibility to quantify muscle dysfunction in DM1.

Efficacy and Safety of Rozanolixizumab in Moderate to Severe Generalized Myasthenia Gravis: A Phase 2 Randomized Control Trial

OBJECTIVE

To explore the clinical efficacy and safety of subcutaneous (SC) rozanolixizumab, an anti-neonatal Fc receptor humanized monoclonal antibody, in patients with generalized myasthenia gravis (gMG).

METHODS

In this phase 2a, randomized, double-blind, placebo-controlled, 2-period, multicenter trial (NCT03052751), patients were randomized (1:1) in period 1 (days 1-29) to 3 once-weekly (Q1W) SC infusions of rozanolixizumab 7 mg/kg or placebo. In period 2 (days 29-43), patients were re-randomized to either rozanolixizumab 7 mg/kg or 4 mg/kg (3 Q1W SC infusions), followed by an observation period (days 44-99). Primary endpoint was change from baseline to day 29 in Quantitative Myasthenia Gravis (QMG) score. Secondary endpoints were change from baseline to day 29 in MG-Activities of Daily Living (MG-ADL) and MG-Composite (MGC) scores and safety.

RESULTS

Forty-three patients were randomized (rozanolixizumab 21, placebo 22 [period 1]). Least squares (LS) mean change from baseline to day 29 for rozanolixizumab vs placebo was as follows: QMG (LS mean -1.8 vs -1.2, difference -0.7, 95% upper confidence limit [UCL] 0.8; p = 0.221; not statistically significant), MG-ADL (LS mean -1.8 vs -0.4, difference -1.4, 95% UCL -0.4), and MGC (LS mean -3.1 vs -1.2, difference -1.8, 95% UCL 0.4) scores. Efficacy measures continued to improve with rozanolixizumab 7 mg/kg in period 2. The most common adverse event in period 1 was headache (rozanolixizumab 57%, placebo 14%).

CONCLUSION

Whereas change from baseline in QMG was not statistically significant, the data overall suggest rozanolixizumab may provide clinical benefit in patients with gMG and was generally well tolerated. Phase 3 evaluation is ongoing (NCT03971422).

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that for patients with gMG, rozanolixizumab is well-tolerated, but did not significantly improve QMG score.

Outcome Measures in Clinical Trials of Patients With Myasthenia Gravis

Myasthenia gravis (MG) is a heterogeneous disorder whose clinical presentation ranges from mild ocular deficits to severe widespread weakness. This variance poses a challenge when quantifying clinical deficits. Deficits and symptoms are quantified using standardized clinical scales and questionnaires which are often used as outcome measures. The past decades have seen the development of several validated outcome measures in MG, which are used in clinical trials to obtain regulatory approval. In recent years, emphasis has moved from objective assessments to patient-reported outcomes. Despite a growing body of literature on the validity of the MG-specific outcome measures, several unresolved factors remain. As several novel therapeutics are currently in clinical development, knowledge about capabilities and limitations of outcome measures is needed. In the present paper, we describe the most widely used clinical classifications and scales in MG. We highlight the choice of outcome measures in published and ongoing trials, and we denote whether trial efficacy was reached on these outcomes. We discuss advantages and limitations of the individual scales, and discuss some of the unresolved factors relating to outcome assessments in MG.

Association of Hospital-Diagnosed Infections and Antibiotic Use With Risk of Developing Guillain-Barré Syndrome

OBJECTIVE

To determine whether hospital-diagnosed and community-treated infections are important Guillain-Barré syndrome (GBS) risk factors, we investigated the magnitude and duration of associated GBS risk.

METHODS

We conducted a nationwide population-based case-control study of all patients with first-time hospital-diagnosed GBS in Denmark between 1987 and 2016 and 10 matched population controls per case. Hospital-diagnosed infections were determined in the 1987-2016 period and community antibiotic prescriptions in the 2004-2016 period. We used conditional logistic regression to examine the relative risk of GBS associated with having a recent infection.

RESULTS

Hospital-diagnosed infections within 60 days were observed in 4.3% of 2,414 GBS cases vs 0.3% of 23,909 controls, with a matched odds ratio (OR) of 13.7 (95% confidence interval [CI], 10.2-18.5). The strongest association with subsequent GBS was observed for lower respiratory tract infection, gastrointestinal tract infection, and septicemia. Community antibiotic prescriptions within 60 days were observed in 22.4% of 1,086 GBS cases and 7.8% of 10,747 controls, with a matched OR of 3.5 (95% CI, 3.0-4.1). The risk of GBS declined considerably with time since infection, with high ORs of 21.3 (95% CI, 14.5-31.2) and 4.7 (95% CI, 3.9-5.7) observed within the first month after a hospital-diagnosed infection and a community antibiotic prescription, respectively. However, GBS risk remained increased 2.4-fold (95% CI, 1.1-5.5) and 1.5-fold (95% CI, 1.2-2.0) even in the fifth month after infection.

CONCLUSION

There is a strong, temporal association between community antibiotic use and especially infections necessitating hospitalization and risk of subsequent GBS.

Small and large fiber sensory polyneuropathy in type 2 diabetes: Influence of diagnostic criteria on neuropathy subtypes

Diabetic polyneuropathy (DPN) can be classified based on fiber diameter into three subtypes: small fiber neuropathy (SFN), large fiber neuropathy (LFN), and mixed fiber neuropathy (MFN). We examined the effect of different diagnostic models on the frequency of polyneuropathy subtypes in type 2 diabetes patients with DPN. This study was based on patients from the Danish Center for Strategic Research in Type 2 Diabetes cohort. We defined DPN as probable or definite DPN according to the Toronto Consensus Criteria. DPN was then subtyped according to four distinct diagnostic models. A total of 277 diabetes patients (214 with DPN and 63 with no DPN) were included in the study. We found a considerable variation in polyneuropathy subtypes by applying different diagnostic models independent of the degree of certainty of DPN diagnosis. For probable and definite DPN, the frequency of subtypes across diagnostic models varied from: 1.4% to 13.1% for SFN, 9.3% to 21.5% for LFN, 51.4% to 83.2% for MFN, and 0.5% to 14.5% for non-classifiable neuropathy (NCN). For the definite DPN group, the frequency of subtypes varied from: 1.6% to 13.5% for SFN, 5.6% to 20.6% for LFN, 61.9% to 89.7% for MFN, and 0.0% to 6.3% for NCN. The frequency of polyneuropathy subtypes depends on the type and number of criteria applied in a diagnostic model. Future consensus criteria should clearly define sensory functions to be tested, methods of testing, and how findings should be interpreted for both clinical practice and research purpose.

Statin Therapy and Risk of Polyneuropathy in Type 2 Diabetes: A Danish Cohort Study

OBJECTIVE

Statins may reduce the risk of diabetic polyneuropathy (DPN) as a result of lipid-lowering and anti-inflammatory effects, but statins have also been associated with neurotoxicity. We examined whether statin therapy affects the risk of DPN.

RESEARCH DESIGN AND METHODS

We identified all Danish patients with incident type 2 diabetes during 2002-2016. New users initiated statins between 180 days before and 180 days after their first diabetes record, while prevalent users had initiated statins before that period. Patients were followed for incident DPN using validated hospital diagnosis codes, starting 180 days after their first diabetes record. Cox proportional hazard analysis was used to compute adjusted hazard ratios (aHRs) for DPN.

RESULTS

The study cohort comprised 59,255 (23%) new users, 75,528 (29%) prevalent users, and 124,842 (48%) nonusers; median follow-up time was 6.2 years (interquartile range 3.4-9.6). The incidence rate of DPN events per 1,000 person-years was similar in new users (4.0 [95% CI 3.8-4.2]), prevalent users (3.8 [3.6-3.9]), and nonusers (3.8 [3.7-4.0]). The aHR for DPN was 1.05 (0.98-1.11) in new users and 0.97 (0.91-1.04) in prevalent users compared with statin nonusers. New users had a slightly increased DPN risk during the first year (1.31 [1.12-1.53]), which vanished after >2 years of follow-up. Findings were similar in on-treatment and propensity score-matched analyses and with additional adjustment for pretreatment blood lipid levels.

CONCLUSIONS

Statin therapy is unlikely to increase or mitigate DPN risk in patients with type 2 diabetes, although a small acute risk of harm cannot be excluded.