INTRODUCTION/AIMS:Nerve cross-sectional area (CSA) is the most robust and sensitive ultrasonographic indicator of nerve pathology. The study aimed to identify predictors of maximal CSA (CSAmax) in ulnar neuropathy at the elbow (UNE) and to assess its utility in elucidating the mechanism of UNE, which is potentially important for patient referral to a surgeon. METHODS:In a group of prospectively recruited UNE patients, 11 demographic, clinical, and electrodiagnostic features were recorded. CSAmax in the elbow segment was measured ultrasonographically. Explanatory variables for CSAmax were determined using a backward stepwise method of multiple linear regression analysis. To determine the CSAmax threshold with the best differentiation of retrocondylar compression and cubital tunnel entrapment (i.e., the UNE mechanism), a ROC curve was constructed. RESULTS:We studied 130 patients (94 men), aged 27-88 years (median 62 years). The only significant predictor of CSAmax was the mechanism of UNE (CSAmax = 7.49 + 6.89 UNE mechanism, SE 1.04, (adjusted) R 2 = 0.25, p < 0.0001). The best differentiation between UNE mechanisms was obtained at the CSAmax of 16 mm2 (sensitivity 0.80, positive predictive value 0.71). DISCUSSION:In UNE, the main determinant of CSAmax was the mechanism of neuropathy. In the UNE of unclear mechanism, CSAmax larger than 16 mm2 is more in favor of a cubital tunnel entrapment. These findings suggest that US is more sensitive in the diagnosis of entrapment compared with compression neuropathies.

INTRODUCTION/AIMS:Ultrasound (US)-guided perineural injection therapy (PIT) with corticosteroids (CS) or 5% dextrose in water (D5W) is commonly used to relieve symptoms in carpal tunnel syndrome (CTS). However, comparative data beyond short-term follow-up are limited. This study aimed to compare the efficacy of US-guided PIT using D5W and CS over a 12-month follow-up period. METHODS:Patients with bilateral mild to moderate CTS participated in a randomized, double-blind, within-subject trial. Each patient's right hand was randomly assigned to receive D5W or CS, while the contralateral hand received the alternate treatment. Primary outcomes included the Boston Carpal Tunnel Questionnaire symptom severity (BCTQs) and functional status (BCTQf) scales and the Visual Analogue Scale (VAS). A single US-guided PIT was performed using 6 mL of injectate: 5% dextrose or triamcinolone acetonide diluted with saline. Clinical assessment, nerve conduction studies, and ultrasonography were performed at baseline and at 1, 3, 6, and 12 months. RESULTS:Fifty-seven patients (114 hands) were included in the analysis. Both D5W and CS produced similar improvements, with the greatest symptom relief observed within the first 3 months. Clinically meaningful improvement in BCTQs was observed in approximately 50% of hands in both groups at 1 and 3 months, and in 29% (D5W) and 25% (CS) at 12 months. DISCUSSION:US-guided PIT with D5W and CS provides comparable clinical benefit over 12 months in mild to moderate CTS, with maximal improvement occurring early after treatment. These results support D5W as a reasonable non-steroidal alternative for perineural injection therapy in CTS.

In non-vasculitic immune-mediated neuropathies, imaging studies demonstrate an enlargement not only of clinically involved but also of clinically intact nerves. The present study aimed to present a pattern of nerve swelling and its relation to nerve function. In a group of patients with dysimmune motor and sensorimotor mononeuropathies, nerve cross-sectional areas (CSAs) were measured using ultrasonography (US) and compound muscle action potential (CMAP) amplitudes using electrodiagnostic (EDx) studies. Nerve CSAs were compared in (1) clinically involved, (2) swollen and clinically uninvolved, and (3) non-swollen (clinically uninvolved) nerves. Patients' non-swollen nerves were also compared to those of controls. In swollen nerves, the correlation between nerve CSA and CMAP amplitude was calculated. Twenty-two patients (12 men) and 50 controls (28 men) were included in the study. Clinically involved nerves were thicker than swollen segments of clinically intact nerves (p < 0.001). The patients' non-swollen (clinically uninvolved) nerves were thicker than the controls'. In swollen nerves, CSA was strongly negatively correlated with CMAP amplitude (r = -0.54, p < 0.001). In patients with immune-mediated mononeuropathies, nerve swelling correlates with clinical and EDx findings. Patients' clinically uninvolved nerves were also swollen, but to a lesser degree.

Consensus was sought from 17 nominated global expert leaders to provide guidance on the combined use of neuromuscular ultrasound (NMUS) and electrodiagnostic tests (EDX) in the investigation of peripheral neuropathy (PN) in clinical practice. Consensus was based on an initial systematic review of the literature by the experts themselves, followed by three anonymised surveys, using the Delphi method. No consensus was defined as < 60 % rating frequency. The panel agreed that NMUS should be used if EDX cannot differentiate an axonal from a demyelinating process or an acquired from a hereditary process, and in the investigation of vasculitic neuropathy; NMUS of the brachial plexus should be used in Guillain-Barre' syndrome if EDX is negative; when NMUS is used, at least two nerves of the upper limbs should be scanned; NMUS should be used for screening or repeat testing for carpal tunnel syndrome in children with mucopolysaccharidoses. Areas of disagreement exposed gaps in current knowledge and informed the direction of future research, which should aim to identify situations in which NMUS can stand alone as a diagnostic test, particularly for screening or repeat testing and especially in vulnerable individuals and paediatric populations.

Background: We aimed to determine the utility of different electrodiagnostic (EDx) methods in diagnosing meralgia paresthetica (MP). Methods: Twenty-nine MP patients and 26 controls were included. Sensory nerve action potential (SNAP) and somatosensory evoked potential (SEP) of the lateral femoral cutaneous nerve (LFCN) and tibial SEPs were measured bilaterally. Results: At least one LFCN SNAP was unobtainable in 18 patients (62%) and two controls (8%). In all remaining 11 patients, SNAPs were abnormal at least unilaterally. By contrast, LFCN SEPs were recorded bilaterally in all subjects and were abnormal in 16 patients (sensitivity 48%). Patients’ tibial SEP latency was significantly larger than that of controls (p < 0.001). Conclusions: LFCN NCSs are superior to SEP in the evaluation of MP. However, SEP studies may be useful in old (>60 years) and obese subjects with unobtainable LFCN SNAP. Longer tibial SEP points to subclinical neuropathy in MP patients predisposed to LFCN entrapment.

Background: The role of ultrasonography (US) in the practical management of polyneuropathies, particularly axonal, remains unclear. The present study aimed to explore the contribution of the US examination of polyneuropathies in daily clinical practice. Methods: We performed a retrospective chart review of patients with clinical and electrophysiological diagnoses of polyneuropathy referred to our US laboratory over eight years. The contribution of US examination in this patient population was evaluated. Results: We analyzed 201 consecutive patients (66% men), aged 12–90 years (mean (SD), 62 (15) years). The most common referral questions were differentiation of hereditary from acquired demyelinating polyneuropathies (71 (35%) patients, sensitivity 63%, specificity 88%), and additional focal neuropathies in patients with generalized neuropathies (51 (25%) patients, sensitivity 75%, specificity 34%). The US examination was pathological in 158 (79%) of patients. The most common US finding was nerve enlargement at typical entrapment sites (73 (36%) patients), followed by proximal nerve thickening (34 (17%) patients). The US provided new diagnoses in 7 (3.5%) patients, contributed to diagnoses in 39 (19%) patients, and confirmed diagnoses in 50 (25%) patients. Conclusion: Our study demonstrated the ability of peripheral nerve US to provide useful additional diagnostic information in about half of the referred patients with polyneuropathy.

INTRODUCTION/AIMS:Diagnostic criteria for multifocal motor neuropathy (MMN) and multifocal acquired demyelinating sensorimotor neuropathy (MADSAM) require the involvement of at least two peripheral nerves. However, many patients with very similar features have clinical involvement of only a single peripheral nerve, which may preclude their correct diagnosis and treatment. The present study aimed to present a cohort of such patients and discuss the role of ultrasonography (US) in their diagnosis. METHODS:Patients with nonvasculitic immune-mediated motor mononeuropathies (MM) and sensorimotor mononeuropathies (SMM) were recruited prospectively or identified from the electronic records. They were invited to comprehensive follow-up visits consisting of clinical examination, electrodiagnostic (EDx), and US studies. RESULTS:Twenty-four patients (13 men) were studied (11 with MM). The characteristics of MM and SMM patients were very similar to MMN and MADSAM, respectively. The US, in addition to a long-swollen segment (average length, 20 cm) in the clinically affected nerve, revealed nerve swelling in, on average, six additional sites in clinically unaffected nerves. DISCUSSION:In patients with clinical and EDx involvement of only a single nerve, an US demonstration of multifocal peripheral nerve swelling points to a more widespread, probably dysimmune mechanism. Further studies are needed to evaluate the value of US as a supplementary method for the diagnosis of MADSAM and MMN in patients with clinical involvement of a single nerve.

The growing threat of antibiotic resistance necessitates accurate differentiation between bacterial and viral infections for proper antibiotic administration. In this study, a Virus vs. Bacteria machine learning model was developed to distinguish between these infection types using 16 routine blood test results, C-reactive protein concentration (CRP), biological sex, and age. With a dataset of 44,120 cases from a single medical center, the model achieved an accuracy of 82.2 %, a sensitivity of 79.7 %, a specificity of 84.5 %, a Brier score of 0.129, and an area under the ROC curve (AUC) of 0.905, outperforming a CRP-based decision rule. Notably, the machine learning model enhanced accuracy within the CRP range of 10-40 mg/L, a range where CRP alone is less informative. These results highlight the advantage of integrating multiple blood parameters in diagnostics. The "Virus vs. Bacteria" model paves the way for advanced diagnostic tools, leveraging machine learning to optimize infection management.

In ulnar neuropathy at the elbow (UNE), the degree of neuropathic changes, the sensitivity of needle electromyography (EMG) in individual ulnar muscles, and the utility of individual EMG parameters are controversial. I compared qualitative needle EMG findings in two ulnar-innervated hands muscles and two ulnar-innervated forearm muscles in a group of previously reported UNE patients. Altogether, 170 UNE patients (175 arms) were studied. I found spontaneous denervation activity (SDA) most frequently in the first dorsal interosseus (FDI) (62%) and neuropathic changes in the abductor digiti minimi (ADM) muscle (88%). In the forearm muscles, SDA was more common (29% vs. 20%; p = 0.02), and neuropathic changes were similar in the flexor carpi ulnaris (FCU) and the flexor digitorum profundus (FDP) muscles. SDA and neuropathic changes were more common in the ulnar hand (88% and 77%) than in the ulnar forearm muscles (71% and 68%). Needle EMG is sensitive to diagnose UNE. For the detection of SDA FDI and neuropathic changes, ADM is the best muscle. Ulnar forearm muscles are less useful than ulnar hand muscles for UNE diagnosis.

BackgroundFunctional neurological disorder (FND) is a common cause of neurological disability. Despite recent advances in pathophysiological understanding and treatments, application of this knowledge to clinical practice is variable and limited.ObjectiveOur aim was to provide an expert overview of the state of affairs of FND practice across Europe, focusing on education and training, access to specialized care, reimbursement and disability policies, and academic and patient-led representation of people with FND.MethodsWe conducted a survey across Europe, featuring one expert per country. We asked experts to compare training and services for people with FND to those provided to people with multiple sclerosis (MS).ResultsResponses from 25 countries revealed that only five included FND as a mandatory part of neurological training, while teaching about MS was uniformly included. FND was part of final neurology examinations in 3/17 countries, unlike MS that was included in all 17. Seventeen countries reported neurologists with an interest in FND but the estimated mean ratio of FND-interested neurologists to MS neurologists was 1:20. FND coding varied, with psychiatric coding for FND impacting treatment access and disability benefits in the majority of countries. Twenty countries reported services refusing to see FND patients. Eight countries reported an FND special interest group or network; 11 reported patient-led organizations.ConclusionsFND is largely a marginal topic within European neurology training and there is limited access to specialized care and disability benefits for people with FND across Europe. We discuss how this issue can be addressed at an academic, healthcare and patient organization level.

Introduction: There are three main potential mechanisms of recovery after nerve lesion: (1) resolution of conduction block, (2) collateral reinnervation, and (3) nerve regeneration. Their relative contributions in recovery after focal neuropathies are not well established. Methods: In a group of previously reported prospective cohort of patients with ulnar neuropathy at the elbow (UNE), I performed a post-hoc analysis of their clinical and electrodiagnostic findings. I compared amplitudes of the compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) on ulnar nerve stimulation, as well as qualitative concentric needle electromyography (EMG) findings in the abductor digiti minimi muscle on the initial and follow-up examinations several years later. Results: Altogether, 111 UNE patients (114 arms) were studied. During median follow-up period of 880 days (range: 385-1545 days), CMAP amplitude increased (p = 0.02), and conduction block in the elbow segment recovered (from median 17% to 7%; p < 0.001). By contrast, SNAP amplitude did not change (p = 0.89). On needle EMG, spontaneous denervation activity diminished (p < 0.001), motor unit potential (MUP) amplitude increased (p < 0.001), and MUP recruitment remained unchanged (p = 0.43). Conclusions: Findings of the present study indicate that nerve function in chronic focal compression/entrapment neuropathies seems to improve mainly due to the resolution of the conduction block and collateral reinnervation. Contribution of nerve regeneration seems to be minor; the majority of axons lost in chronic focal neuropathies probably never recover. Further studies using quantitative methods are needed to validate present findings.

BACKGROUND:Peripheral nerve tumours (PNTs) are rare, but important cause of peripheral nerve dysfunction. The aim of the study was to present a series of consecutive patients with PNTs evaluated in authors' ultrasonography (US) practice. PATIENTS AND METHODS:The electronic medical records of patients with PNTs examined at our US laboratory from February 2013 to May 2020 were retrospectively reviewed. Data on gender, age, clinical features, PNT location, electrodiagnostic (EDx) features and US findings were collected. RESULTS:In the analyzed period 2845 patients were examined in our US laboratory. From these 15 patients (0.5%) with PNTs were identified. Four of them (3 with confirmed neurofibromatosis) had multiple PNTs. Half of patients (53%) presented with features of peripheral nerve damage, and others with palpable mass or pain. The most often involved nerve was ulnar (36%). PNT cross sectional areas varied from 24 mm2 to 1250 mm2 (median, 61 mm2). Based in 5 patients on histological and in remaining patients on US features, schwannoma was diagnosed in 40%, neurofibroma in 27%, and perineurioma in 27% of patients. CONCLUSIONS:As in previous reports, PNTs in our series presented with neurological symptoms, palpable mass or pain. In contrast to other focal neuropathies, particularly nerves with schwannomas, in spite of their large thickening, often demonstrated well preserved function. Adding US to our clinical practice, enabled us to diagnose these rare peripheral nerve lesions that we missed before.

Expert consensus was sought to guide clinicians on the use of electrodiagnostic tests (EDX) and neuromuscular ultrasound (NMUS) in the investigation of suspected carpal tunnel syndrome (CTS). Consensus was achieved using the Delphi method via three consecutive anonymised surveys of 15 experts and was defined as rating agreement >= 80%. The panel agreed that combining EDX and NMUS is more informative than using each modality alone. NMUS adds value in patients with clinically suspected CTS with non-localizing or normal EDX, atypical EDX, failed CTS surgery, polyneuropathy, and CTS suspected to be secondary to structural pathology. The median nerve cross-sectional area should be measured at the site of maximal nerve enlargement, and the nerve should be scanned from mid-forearm to the palm. The group also identified those situations where the wrist-to-forearm area ratio and longitudinal scans of the median nerve should also be obtained. EDX should always be performed to quantify CTS severity and in individuals over age 70. This document is an initial step to guide clinicians on the combined investigation of CTS using EDX and NMUS, to be updated regularly with the emergence of new research. (C) 2022 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Objective: To establish length of the affected nerve segment (LANS) in ulnar neuropathy at the elbow (UNE). Methods: In a group of our previously reported UNE patients we identified 2-cm segments with reduced motor nerve conduction velocity (MNCV) on electrodiagnostic (EDx) studies and increased nerve cross-sectional areas (CSA) on ultrasonographic (US) studies. LANS was obtained by summation of these abnormal 2-cm segments separately for each approach. We also studied effect of selected independent parameters on LANS. Results: Altogether we studied 189 patients (194 arms). Mean (SD) LANS determined in 171 arms with reduced ulnar MNCV was 4.15 (1.89) cm, and was similar (p = 0. 21) to LANS obtained in 147 arms with increased CSA 4.46 (2.29) cm. Longer LANS were found in right arms, clinically severe UNE, axonal UNE and UNE due to entrapment. The most commonly affected 6 cm segment included 89% of abnormal 2-cm segments, with 50% of included 2-cm segments being normal. By contrast, the whole 10 cm segment included all abnormal 2-cm segments, with 66% of included segments being normal. Conclusions: In UNE both EDx and US studies revealed average LANS of around 4 cm. LANS was longer in more severe UNE. Significance: LANS needs to be taken into account in discussion of the mechanisms of UNE and approach to EDx diagnosis of UNE, particularly length of the segment used in nerve conduction studies across the elbow. (C) 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Introduction/AimsAn important mechanism of peripheral nerve motor and sensory dysfunction is conduction block (CB). However, recovery from mechanically induced CB has been rarely studied in humans. The aim of this study was to describe clinical, electrodiagnostic (EDx), and ultrasonographic (US) characteristics of CB recovery in ulnar neuropathy at the elbow (UNE). MethodsWe recruited a group of consecutive patients presenting to our EDx laboratory with UNE and >50% motor CB. Patients' histories were obtained and neurologic, EDx, and US examinations were repeated every 1-3 mo for at least 12 mo. ResultsWe studied 10 patients (5 men), with a mean age of 63 y (range, 51-81 y). In all affected arms CB was localized to the retrocondylar groove. Following conservative management, myometrically measured index finger abduction improved from a median of 49% to 100% relative to the contralateral index finger, and ulnar nerve CB decreased from a median of 74% to 6%. Most of the improvement took place within 8 mo of symptom onset, and 6 mo after receiving treatment instructions. Mean motor nerve conduction velocity improved from 15 to 27 m/s in the most affected 2-cm ulnar nerve segment. DiscussionThe resolution of CB after typical chronic compression may take longer than after acute compression. This should be considered by clinicians when estimating prognosis for discussions with patients.

Physicians taking care of patients with COVID-19 have described different changes in routine blood parameters. However, these changes hinder them from performing COVID-19 diagnoses. We constructed a machine learning model for COVID-19 diagnosis that was based and cross-validated on the routine blood tests of 5333 patients with various bacterial and viral infections, and 160 COVID-19-positive patients. We selected the operational ROC point at a sensitivity of 81.9% and a specificity of 97.9%. The cross-validated AUC was 0.97. The five most useful routine blood parameters for COVID-19 diagnosis according to the feature importance scoring of the XGBoost algorithm were: MCHC, eosinophil count, albumin, INR, and prothrombin activity percentage. t-SNE visualization showed that the blood parameters of the patients with a severe COVID-19 course are more like the parameters of a bacterial than a viral infection. The reported diagnostic accuracy is at least comparable and probably complementary to RT-PCR and chest CT studies. Patients with fever, cough, myalgia, and other symptoms can now have initial routine blood tests assessed by our diagnostic tool. All patients with a positive COVID-19 prediction would then undergo standard RT-PCR studies to confirm the diagnosis. We believe that our results represent a significant contribution to improvements in COVID-19 diagnosis.