Neuromuscular ultrasound standardized scanning techniques and protocols: Expert panel recommendations

Neuromuscular ultrasound has become an integral part of the diagnostic workup of neuromuscular disorders at many centers. Despite its growing utility, uniform standard scanning techniques do not currently exist. Scanning approaches for similar diseases vary in the literature creating heterogeneity in the studies as reported in several meta-analysis. Moreover, neuromuscular ultrasound experts including the group in this study have different views with regards to technical aspects, scanning protocols, and the parameters that should be assessed. Establishing standardized neuromuscular scanning protocols is essential for the development of the subspeciality to ensure uniform clinical and research practices. Therefore, we aimed to recommend consensus-based standardized scanning techniques and protocols for common neuromuscular disorders using the Delphi approach. A panel of 17 experts participated in the study, which consisted of three consecutive electronic surveys. The first survey included voting on six scanning protocols addressing the general scanning technique and five common categories of suspected neuromuscular disorders. The subsequent surveys focused on refining the protocols and voting on new steps, rephrased statements, or areas of non-agreement. A high degree of consensus was achieved on the general neuromuscular ultrasound scanning technique and the scanning protocols for focal mononeuropathies, brachial plexopathies, polyneuropathies, amyotophic lateral sclerosis, and muscle diseases. In this study, a group of neuromuscular ultrasound experts developed six consensus-based neuromuscular ultrasound scanning protocols that may serve as references for clinicians and researchers. The standardized protocols could also aid in achieving high-quality uniform neuromuscular ultrasound practices.

Evidence-based guideline: Neuromuscular ultrasound for the diagnosis of ulnar neuropathy at the elbow

INTRODUCTION/AIMS

The purpose of this literature review is to develop an evidence-based guideline for the use of neuromuscular ultrasound in the diagnosis of ulnar neuropathy at the elbow (UNE). The proposed research question was: "In patients with suspected UNE, does ulnar nerve enlargement as measured with ultrasound accurately identify those patients with UNE?"

METHODS

A systematic review and meta-analysis was performed, and studies were classified according to American Academy of Neurology criteria for rating articles for diagnostic accuracy.

RESULTS

Based on Class I evidence in four studies, it is probable that neuromuscular ultrasound measurement of the ulnar nerve at the elbow, either of diameter or cross-sectional area (CSA), is accurate for the diagnosis of UNE.

RECOMMENDATION

For patients with symptoms and signs suggestive of ulnar neuropathy, clinicians should offer ultrasonographic measurement of ulnar nerve cross-sectional area or diameter to confirm the diagnosis and localize the site of compression (Level B).

American Academy of Neurology Telehealth Position Statement

Telehealth services complement in-person neurologic care. The American Academy of Neurology supports patient access to telehealth services regardless of location, coverage for telehealth services by all subscriber benefits and insurance, equitable provider reimbursement, simplified state licensing requirements easing access to virtual care, and expanding telehealth research and quality initiatives. The roles and responsibilities of providers should be clearly delineated in telehealth service models.

Enhancing diagnostic accuracy using a side-to-side cross-sectional area ratio for the diagnosis of unilateral ulnar mononeuropathy at the elbow

INTRODUCTION

Neuromuscular ultrasonography (NMUS) is a valuable adjunct to electrodiagnostic testing for the diagnosis of entrapment neuropathy. The aim of this study was to determine whether diagnostic accuracy of NMUS could be enhanced in patients with unilateral ulnar mononeuropathy at the elbow (UNE) by utilizing side-to-side ulnar nerve cross-sectional area (CSA) ratios.

METHODS

Retrospective case-control analysis of unilateral UNE cases identified cutoff values for elbow segment ulnar nerve maximum CSA (MCSA) of the symptomatic/asymptomatic limb (M ratio), as well as side-to-side ratios comparing MCSA with ipsilateral CSA at the Guyon canal (E/G), middle forearm (E/F), and middle humerus (E/H). Diagnostic accuracy values were calculated.

RESULTS

The optimal M-ratio cut-off was 1.22 (sensitivity, 92.9%; specificity, 97.8%; accuracy, 95.4%). Optimal cutoffs for inter-E/G, -E/F, and -E/H ratios were 1.07 (sensitivity, 98%; specificity, 78%; accuracy, 87.7%), 1.11 (sensitivity, 95%; specificity, 80%; accuracy, 87.2%), and 1.18 (sensitivity, 95%; specificity, 93%; accuracy, 94%), respectively.

DISCUSSION

The M ratio and inter-E/H ratio exhibited high diagnostic accuracy for unilateral UNE. Prospective studies are needed to compare the accuracy of the new measures with a single MCSA measurement.

Ultrasound in the diagnosis and management of fibular mononeuropathy

INTRODUCTION

Ultrasound (US) evaluation of peripheral nerves is a noninvasive, cost-effective approach to diagnosing focal mononeuropathies and guiding surgical management. We used the intranerve ratio to evaluate for possible cut-off values in diagnosis of fibular mononeuropathies (FNs).

METHODS

A retrospective analysis of FN confirmed by electrodiagnosis (EDx) was performed to identify intranerve ratio values between affected and unaffected limbs at the fibular head and popliteal fossa.

RESULTS

The optimal fibular head/popliteal fossa intranerve ratio to discriminate between limbs with and without disease was 1.25 (sensitivity, 51%; specificity, 71%). There was no statistically significant difference between affected vs unaffected limbs (ratio, 1.13; P = .15) nor in subgroup analyses. However, 25% of patients had structural lesions amenable to surgery.

DISCUSSION

The utility of US in diagnosis of FN is limited using intranerve ratio data, but US has a distinct advantage over EDx for identifying treatable structural lesions.

Association of statin pretreatment with collateral circulation and final infarct volume in acute ischemic stroke patients: A meta-analysis

BACKGROUND AND AIMS

Statin pretreatment (SP) is associated with improved outcomes in acute ischemic stroke (AIS) patients. Collateral circulation status and final infarct volume (FIV) are independent predictors of functional outcome in AIS.

METHODS

We sought to evaluate the association of SP with collateral circulation and FIV in AIS patients. We used a random-effects model for all the analyses, and pooled standardized mean differences (SMDs) and odds ratios (OR) on the FIV and collateral status according to SP history, respectively.

RESULTS

We identified 9 eligible studies (1186 AIS patients). History of SP was associated with lower FIV (SMD = 0.25, 95%CI: 0.07-0.42, p = 0.005) compared to negative history of SP. A trend towards good collateral scores was observed in the SP group (OR = 1.45; 95% CI, 0.92-2.29, p = 0.11). Subgroup analysis demonstrated reduced FIV among atherosclerotic stroke patients with history of SP (SMD = 0.49; 95% CI, 0.19-0.80, p = 0.001).

CONCLUSIONS

SP appears to be associated with decreased FIV, especially in atherosclerotic AIS.

Modeling of Lung Function Recovery in Neuralgic Amyotrophy With Diaphragm Impairment

BACKGROUND

Neuralgic amyotrophy is an inflammatory peripheral nerve disorder in which phrenic nerve involvement can lead to diaphragm paralysis. The prevalence, magnitude, and time course of diaphragm recovery are uncertain.

METHODS

This study modeled the course of recovery of lung function in 16 subjects with diaphragm impairment from neuralgic amyotrophy. The first and last available vital capacity, sitting-to-supine decline in vital capacity, and maximal inspiratory pressures were compared.

RESULTS

An asymptotic regression model analysis in 11 subjects with at least partial recovery provided estimates of the vital capacity at onset (47%, 95% CI 25-68%), the final vital capacity (81%, 95% CI 62-101%), and the half-time to recovery (22 months, 95% CI 15-43 months). In those subjects, there was a significant improvement between the first and last measured FVC (median 44-66%, P = .004) and maximal inspiratory pressure (mean 34-51%, P = .004). Five subjects (31%) with complete recovery had a final sitting-to-supine drop of vital capacity of 16% and a maximal predicted inspiratory pressure of 63%.

CONCLUSIONS

Sixty-nine percent of subjects with diaphragm impairment from neuralgic amyotrophy experience recovery of lung function and diaphragm strength, but recovery is slow and may be incomplete.

Intraneural nodular fasciitis of the radial nerve with rapidly progressive motor symptoms

Background:

Nodular fasciitis is a benign mesenchymal tumor arising from fascia that typically presents as a rapidly growing, subcutaneous mass. Intraneural cases are very rare and can present with neurological symptoms, requiring surgical resection.

Case Description:

A 31-year-old woman presented to us with painful paresthesias in her elbow and progressive motor deficits, for which she underwent surgery.

Conclusion:

The authors report the first case of intraneural nodular fasciitis occurring in the radial nerve and highlight the possibility of rapidly progressive motor deficit in patients presenting with this rare clinical entity.

Evidence-based guideline: neuromuscular ultrasound for the diagnosis of carpal tunnel syndrome

INTRODUCTION

The purpose of this study was to develop an evidence-based guideline for the use of neuromuscular ultrasound in the diagnosis of carpal tunnel syndrome (CTS).

METHODS

Two questions were asked: (1) What is the accuracy of median nerve cross-sectional area enlargement as measured with ultrasound for the diagnosis of CTS? (2) What added value, if any, does neuromuscular ultrasound provide over electrodiagnostic studies alone for the diagnosis of CTS? A systematic review was performed, and studies were classified according to American Academy of Neurology criteria for rating articles of diagnostic accuracy (question 1) and for screening articles (question 2).

RESULTS

Neuromuscular ultrasound measurement of median nerve cross-sectional area at the wrist is accurate and may be offered as a diagnostic test for CTS (Level A). Neuromuscular ultrasound probably adds value to electrodiagnostic studies when diagnosing CTS and should be considered in screening for structural abnormalities at the wrist in those with CTS (Level B).

A 5-Item Scale to Predict Stroke Outcome After Cortical Middle Cerebral Artery Territory Infarction

Background and Purpose—

Various clinical, laboratory, and radiographic parameters have been identified as predictors of outcome for ischemic stroke. The purpose of this study was to combine these parameters into a validated scale for outcome prognostication in patients with a middle cerebral artery territory infarction.

Methods—

We retrospectively reviewed 129 patients over a 2-year period and considered demographic, clinical, laboratory, and radiographic parameters as potential predictors of outcome. Inclusion criteria were unilateral hemispheric infarcts within the middle cerebral artery territory >15 mm in diameter. Our primary outcome measure was a favorable recovery defined as a modified Rankin Score was ≤2 at 30 days. A multivariable model was used to determine independent predictors of outcome and weighted to create a 5-item scale to predict stroke recovery. External validation of this model was done using data from the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution (DEFUSE) study.

Results—

The 5 independent predictors of outcome were as follows: age (OR, 1.09; 95% CI, 1.03 to 1.14; P =0.001), National Institutes of Health Stroke Scale score (OR, 1.17; 95% CI, 1.06 to 1.30; P =0.003), infarct volume (OR, 1.01; 95% CI, 1.00 to 1.02; P =0.03), admission white blood cell count (8.5×10 3 /mm 3 ; OR, 1.16; 95% CI, 1.03 to 1.27; P =0.04), and presence of hyperglycemia (OR, 4.2; 95% CI, 1.1 to 16.4; P =0.04). Combining these variables into a point scale significantly improved prediction over the individual variables accounted alone as evidenced by the area underneath the receiver operating curve (OR, 0.91; 95% CI, 0.87 to 0.96; P =0.0001). When applied to the DEFUSE study population for validation, the model achieved a sensitivity of 83% and specificity of 86%.

Conclusions—

With validation from a prospective study of similar patients, this model serves as a useful clinical and research tool to predict stroke recovery after cortical middle cerebral artery territory infarction.

Racing against the clock: recognizing, differentiating, diagnosing, and referring the amyotrophic lateral sclerosis patient

Recognition of the early symptoms and signs in amyotrophic lateral sclerosis, exclusion of alternative diagnoses, and referral to a tertiary center can have a significant positive impact on the lives of patients and their caregivers. This article provides the most current amyotrophic lateral sclerosis criteria, as well as helpful clinical clues to the diagnosis. An approach to laboratory testing, electrodiagnostic testing, and imaging to exclude diseases that mimic ALS also are discussed, as are atypical presentations that can confound timely diagnosis.

Novel mutation in KCNA1 causes episodic ataxia with paroxysmal dyspnea

Episodic ataxia type 1 (EA1) is an autosomal-dominant neurological disease caused by point mutations in the potassium channel-encoding gene KCNA1. It is characterized by attacks of ataxia and continuous myokymia. Respiratory muscle involvement has not been previously reported in EA1. We clinically evaluated a family with features of EA1 and paroxysmal shortness of breath. Coding and flanking intronic regions of KCNA1 were sequenced. We identified a novel 3-nucleotide deletion mutation in KCNA1 in the affected individuals. Our findings of a deletion mutation with unusual respiratory muscle involvement expand the genetic and clinical spectrum of EA1.

Statin Use is Independently Associated with Smaller Infarct Volume in Nonlacunar MCA Territory Stroke

BACKGROUND

Studies have shown an association between HMG-CoA reductase inhibitors (statins) and improved stroke outcomes, possibly secondary to neuroprotective properties.

OBJECTIVE

To assess whether patients taking statins prior to ischemic stroke have smaller infarcts on magnetic resonance imaging (MRI), adjusting for other relevant clinical factors.

DESIGN

We retrospectively reviewed the Cleveland Clinic Foundation (CCF) Neurology Inpatient Database from June 2002 through June 2004. Demographics, medications, stroke subtype, diffusion-weighted imaging (DWI) infarct volume, admission NIHSS, and hours to MRI were collected. Patients with a nonlacunar middle cerebral artery (MCA) territory infarct and MRI less than 48 hours from symptom onset were included (n= 143). A multivariable linear regression model was constructed to determine independent predictors of smaller infarct volume.

RESULTS

A total of 143 patients were studied, including 38 patients taking statins at the time of their stroke. In univariate analysis, patients using statins were significantly more likely to have a history of hyperlipidemia, atrial fibrillation, and coronary artery disease and to be using coumadin, antiplatelet drugs, and angiotensin-converting enzyme inhibitors. Patients on statins had a tendency toward smaller infarcts in univariate analysis (median 25.4 cm(3) vs. 15.5 cm(3), P= 0.054). In multivariable linear regression analysis statin use, patient age, and TIA within the prior 4 weeks were independently associated with smaller DWI volumes; vessel occlusion on vascular imaging, and cardioembolic stroke subtype with larger infarct size.

CONCLUSIONS

Statin use prior to the onset of nonlacunar MCA infarction was associated with a smaller infarct volume independent of other factors. Further studies utilizing both clinical and radiologic outcomes will be required to confirm these findings.

Incidence of seizures in patients with multiple sclerosis treated with intrathecal baclofen

Oral and intrathecal baclofen (ITB) have been associated with epileptic seizures. The authors observed a higher incidence of epileptic seizures in 99 patients with multiple sclerosis (MS) treated with ITB vs a matched control group (7% vs 1%, p < 0.05). Three patients with MS on ITB developed status epilepticus. Seizures were often associated with additional triggering factors.

Polymorphism and selection at the SerH immobilization antigen locus in natural populations of Tetrahymena thermophila

The SerH locus of Tetrahymena thermophila is one of several paralogous loci with genes encoding variants of the major cell surface protein known as the immobilization antigen (i-ag). The locus is highly polymorphic, raising questions concerning functional equivalency and selective forces acting on its multiple alleles. Here, we compare the sequences and expression of SerH1, SerH3, SerH4, SerH5, and SerH6. The precursor i-ags are highly similar. They are rich in alanine, serine, threonine, and cysteine and they share nearly identical ER translocation and GPI addition signals. The locations of the 39 cysteines are highly conserved, particularly in the 3.5 central, imperfect tandem repeats in which 8 periodic cysteines punctuate alternating short and long stretches of amino acids. Hydrophobicity patterns are also conserved. Nevertheless, amino acid sequence identity is low, ranging from 60.7 to 82.9%. At the nucleotide level, from 9.7 to 26.7% of nucleotide sites are polymorphic in pairwise comparisons. Expression of each allele is regulated by temperature-sensitive mRNA stability. H mRNAs are stable at <36 degrees but are unstable at >36 degrees. The H5 mRNA, which is less affected by temperature, has a different arrangement of the putative mRNA destabilization motif AUUUA. Statistical analysis of SerH genes indicates that the multiple alleles are neutral. Significantly low ratios of the rates of nonsynonymous to synonymous amino acid substitutions suggest that the multiple alleles are subject to purifying (negative) selection enforcing constraints on structure.