A case series evaluating patient perceptions after switching from nusinersen to risdiplam for spinal muscular atrophy.

INTRODUCTION/AIMS: In 2016, nusinersen became the first disease-modifying medication approved by the U.S. Food and Drug Administration (FDA) for spinal muscular atrophy (SMA). With the later availability of risdiplam in 2020, individuals now have the option of switching from nusinersen to risdiplam. Limited published data exist to inform this decision. This study aims to evaluate the perceptions and experiences of adult participants and parents of minor participants who previously received nusinersen and switched to risdiplam for the treatment of SMA. METHODS: Institutional Review Board (IRB) approval was obtained from the Wake Forest IRB prior to the initiation of this study. A cross-sectional, observational study, with qualitative and quantitative data gathered via questionnaire and medical record review, was performed. Inclusion criteria included (1) prior diagnosis of SMA, (2) previous treatment with nusinersen, and (3) change to treatment with risdiplam. No participants were excluded based on age. RESULTS: Fourteen participants-eight adults and six children-were enrolled in the study. Respondents noted improvements in physical function with each medication. Overall, respondents reported worse satisfaction with the method of delivery of the intrathecally delivered nusinersen compared to the orally-delivered risdiplam, but no respondent reported negative overall satisfaction with either medication. A majority (78.6%) of respondents reported that switching from nusinersen to risdiplam was the correct decision. DISCUSSION: These results suggest that most patients are satisfied when switching from nusinersen to risdiplam, with the method of delivery being a primary factor.

Ultra high-frequency ultrasound of fascicles in the ulnar and radial nerves.

INTRODUCTION/AIMS: Ultra high-frequency ultrasound (UHFUS) has been demonstrated to allow easy visualization and quantification of median and digital nerve fascicles; however, there is a lack of normative data for other upper limb nerves. The purpose of this study was to use UHFUS to establish normative reference values and ranges for fascicle count and density within selected upper extremity nerves. METHODS: Twenty-one healthy volunteers underwent sonographic examination of the ulnar, superficial branch of the radial, and radial nerves on one upper limb using UHFUS with a 48 MHz linear transducer. The number of fascicles in each peripheral nerve and fascicle density were assessed. RESULTS: The mean fascicle number and fascicle density for each of the measured nerves was ulnar nerve at the wrist 11.7 and 2.0, ulnar nerve at the elbow 9.2 and 1.1, superficial branch of the radial nerve 7.3 and 2.5, and radial nerve at the spiral groove 4.2 and 0.8. A single significant association was observed between CSA and fascicle number in the ulnar nerve at the wrist (p = .023, r = 0.66). Neither fascicle number nor density could be predicted by age, sex, height, weight, or body mass index. DISCUSSION: UHFUS may help to establish a baseline of normative data on upper limb nerves that are not frequently biopsied due to their mixed motor and sensory functions and has the potential for increased understanding of nerve fascicular anatomy to improve diagnostic accuracy of focal nerve lesions, particularly those with selective fascicular involvement.

Ultrahigh-frequency ultrasound of fascicles in the common fibular, superficial fibular, and sural nerves.

INTRODUCTION/AIMS: While ultrasound assessment of cross-sectional area and echogenicity has gained popularity as a biomarker for various neuropathies, there is a scarcity of data regarding fascicle count and density in neuropathies or even healthy controls. The aim of this study was to determine whether fascicles within select lower limb nerves (common fibular, superficial fibular, and sural nerves) can be counted in healthy individuals using ultrahigh-frequency ultrasound (UHFUS). METHODS: Twenty healthy volunteers underwent sonographic examination of the common fibular, superficial fibular, and sural nerves on each lower limb using UHFUS with a 48 MHz linear transducer. Fascicle counts and density in each examined nerve were determined by a single rater. RESULTS: The mean fascicle number for each of the measured nerves included the following: common fibular nerve 9.85 (SD 2.29), superficial fibular nerve 5.35 (SD 1.59), and sural nerve 6.73 (SD 1.91). Multivariate linear regression analysis revealed a significant association between cross-sectional area and fascicle count for all three nerves. In addition, there was a significant association seen in the common fibular nerve between fascicle density and height, weight, and body mass index. Age and sex did not predict fascicle count or density (all p > .13). DISCUSSION: UHFUS enabled the identification and counting of fascicles and fascicle density in the common fibular, superficial fibular, and sural nerves. Knowledge about normal values and normal peripheral nerve architecture is needed in order to further understand and identify pathological changes that may occur within each nerve in different disease states.

Determining the degree of proximal nerve fascicle rotation in healthy controls using ultrahigh-frequency neuromuscular ultrasound: A pilot study.

INTRODUCTION/AIMS: Ultrahigh-frequency ultrasound (UHFUS) allows improved visualization and higher resolution images of nerve fascicles than standard high-frequency ultrasound. Dynamic UHFUS may detect the presence of fascicular entwinement, the recently described sonographic phenomenon of pathologic fascicular rotation seen in neuralgic amyotrophy. This pilot study aims to establish normative reference values and degrees of fascicular rotation for the proximal portions of commonly involved upper limb nerves in healthy controls using UHFUS. METHODS: Twenty healthy participants underwent sonographic examination of the median, musculocutaneous, and radial nerves on both upper limbs using UHFUS with a 48 MHz linear transducer. A single rater assessed the degree of fascicular rotation in each peripheral nerve. RESULTS: Fascicular rotation appears to occur in the proximal portion of each of these nerves. The mean degree of fascicular rotation for each of the measured nerves was median 94.5°, musculocutaneous 97.9°, and radial 50.9°. The maximum observed fascicular rotation in each nerve was 180°. Age, sex, height, weight, body mass index, and race did not predict degree of fascicular rotation (all p > .103). A single-factor ANOVA test showed the degree of fascicular rotation differed in median, musculocutaneous, and radial nerves (F = 4.748, p = .011). DISCUSSION: UHFUS allows quantification of fascicular rotation in healthy controls in the median, musculocutaneous, and radial nerves, and provides normative data. The data from this pilot study may serve as control data for future comparative studies in conditions where fascicular rotation occurs, such as neuralgic amyotrophy.

The Role of Neuromuscular Ultrasound in the Diagnosis of Peripheral Neuropathy.

The classification of peripheral neuropathies has traditionally been based on etiology, electrodiagnostic findings, or histopathologic features. With the advent of modern imaging, they now can also be characterized based on their varied distribution of imaging findings. We describe the major morphologic patterns of these changes, which include homogeneous enlargement; homogeneous thinning; focal, multifocal, and segmental enlargement; and focal thinning and beading (multifocal thinning). Representative disorders in each of these categories are discussed, along with examples of the more complex imaging manifestations of neuralgic amyotrophy, nerve transection, and hereditary amyloidosis. An appreciation of the diverse morphologic manifestations of neuropathy can help neuromuscular clinicians conduct appropriate imaging studies with ultrasound and, when needed, order suitable investigations with magnetic resonance neurography.

Neuromuscular Ultrasound in Polyneuropathies.

Neuromuscular ultrasound is a painless, radiation-free, high-resolution imaging technique for assessing the peripheral nervous system. It can accurately depict changes in the nerves and muscles of individuals with neuromuscular conditions, and it is therefore a robust diagnostic tool for the assessment of individuals with polyneuropathies. This review will outline the typical ultrasonographic changes found in a wide variety of polyneuropathies. In general, demyelinating conditions result in greater nerve enlargement than axonal conditions, and acquired conditions result in more patchy nerve enlargement compared to diffuse nerve enlargement in hereditary conditions. This review is data-driven, but more nuanced anecdotal findings are also described. The overall goal of this paper is to provide clinicians with an accessible review of the ultrasonographic approaches and findings in a wide variety of polyneuropathies.

Evaluation of Serum Neurofilament Light Chain and Nerve Ultrasound in Diabetic Neuropathy.

OBJECTIVE: To assess the role of serum neurofilament light chain (NfL) levels in individuals with diabetic polyneuropathy (DPN) compared with controls, as well as to highlight the different sonographic changes in DPN and determine if NfL correlates with sonographic, clinical, and functional parameters. METHODS: Diabetic individuals with signs or symptoms consistent with peripheral nerve involvement were recruited. They were evaluated by examination, functional neuropathy severity scores, laboratory assessments (including NfL), nerve conduction studies (NCS), and ultrasound. Ultrasound was performed of the bilateral median, ulnar, tibial, fibular, sural, and vagus nerves, and cervical roots 5 and 6. Results were compared with age, sex, and body mass index matched healthy controls. RESULTS: A total of 320 nerves from 20 patients and 480 nerves from 30 controls were evaluated. NfL was significantly elevated in those with diabetes with a mean and standard deviation of 6.95 ± 2.95 pg/mL in the diabetic group and 2.83 ± 0.77 pg/mL in controls (P < .001). Nerve cross-sectional area and serum NfL levels correlated significantly with clinical and functional parameters and with each other (P < .05). CONCLUSION: Individuals with DPN have significantly higher NfL levels than healthy controls, and NfL levels correlate with ultrasonographic parameters. These findings may be useful for the diagnosis, prognosis, and disease monitoring of those with DPN, though further exploration is needed.

Short-term educational value of online neuromuscular ultrasound courses.

INTRODUCTION/AIMS: We have previously reported that online neuromuscular ultrasound courses are feasible and were found to be useful by most survey respondents. However, our previous report lacked objective assessment of the educational value of the courses. Therefore, we aimed in this study to evaluate the learning outcomes of online neuromuscular ultrasound courses. METHODS: Each of the basic and advanced courses featured one pre- and two post-course online knowledge tests. The percentage of corrected answers and the participants' scores in the three tests were calculated and compared. RESULTS: A total of 153 out of 277 course participants answered the course test. The mean percentage of correct answers were significantly higher in the second and first post-course tests compared to the pre-course test (Basic course test: 80.2 ± 14.8%, 75.5 ± 15.9%, 64.3 ± 19.1%, respectively; Advanced course test: 80.9 ± 20.1, 78.9 ± 15.2%, 69.5 ± 20.2%, respectively). The mean scores of the participants in the basic course test significantly improved in the first and second post-course tests (from 66.6% to 77.5% and from 67.2% to 80.2%, respectively) whereas those of the participants in the advanced course test significantly improved in the first post-course test only (from 76.3% to 85.4%). DISCUSSION: This report demonstrates the capability of online neuromuscular ultrasound courses, particularly the basic-level courses, to enhance knowledge. This information can further help integrate virtual neuromuscular ultrasound teaching as a standard complementary educational format together with supervised in-person or remote hands-on training.

Sonographic reference values of nerve size in children: A systematic review and meta-analysis.

INTRODUCTION/AIMS: Nerve ultrasound is useful in the diagnosis and follow-up of peripheral nerve disorders in children. The aim of this study was to explore and analyze the current literature on nerve cross-sectional area (CSA) in healthy children, with the goal of presenting reference values and discussing their implications. METHODS: We performed a systematic review and meta-analysis of studies that reported ultrasound measurements of the upper or lower limb nerves in healthy children through a search of Web of Science, PubMed, Embase, and Scopus. RESULTS: Sixteen studies with measurements of 10 nerves covering a total of 5149 nerves measured in 823 healthy children (445 boys and 378 girls) were included. Mean nerve CSA increased with age in the median nerve at the middle and lower third of the upper arm, mid-forearm, and distal wrist crease, the ulnar nerve at the middle third of the upper arm and elbow, the radial nerve at the spiral groove, and the tibial nerve at the popliteal fossa. Growth charts for nerve CSA for different age groups were developed. DISCUSSION: This meta-analysis provides robust reference values for nerve CSA at different sites in children, and this can inform clinical practice and assist in identifying nerve enlargement. Moreover, it identifies the strength and quality of the current published data. We recommend future studies divide their samples into smaller age subgroups and standardize the anatomic site of measurement.

A standardized ultrasound approach in neuralgic amyotrophy.

Neuralgic amyotrophy (NA), also referred to as idiopathic brachial plexitis and Parsonage-Turner syndrome, is a peripheral nerve disorder characterized by acute severe shoulder pain followed by progressive upper limb weakness and muscle atrophy. While NA is incompletely understood and often difficult to diagnose, early recognition may prevent unnecessary tests and interventions and, in some situations, allow for prompt treatment, which can potentially minimize adverse long-term sequalae. High-resolution ultrasound (HRUS) has become a valuable tool in the diagnosis and evaluation of NA. Pathologic HRUS findings can be grouped into four categories: nerve swelling, swelling with incomplete constriction, swelling with complete constriction, and fascicular entwinement, which may represent a continuum of pathologic processes. Certain ultrasound findings may help predict the likelihood of spontaneous recovery with conservative management versus the need for surgical intervention. We recommend relying heavily on history and physical examination to determine which nerves are clinically affected and should therefore be assessed by HRUS. The nerves most frequently affected by NA are the suprascapular, long thoracic, median and anterior interosseous nerve (AIN) branch, radial and posterior interosseous nerve (PIN) branch, axillary, spinal accessory, and musculocutaneous. When distal upper limb nerves are affected (AIN, PIN, superficial radial nerve), the lesion is almost always located in their respective fascicles within the parent nerve, proximal to its branching point. The purpose of this review is to describe a reproducible, standardized, ultrasonographic approach for evaluating suspected NA, and to share reliable techniques and clinical considerations when imaging commonly affected nerves.

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.

Exploration of Neurofilament Light Chain and Nerve Ultrasound in Leprotic Neuropathy.

OBJECTIVES: To explore neurofilament light chain (NfL) levels in leprotic neuropathy compared to controls, and to determine if the changes correlate with ultrasonographic nerve findings. METHODS: Individuals with leprosy with signs or symptoms suggestive of peripheral nerve involvement were recruited. They were evaluated by clinical examination, functional scores, laboratory assessments (including NfL), nerve conduction studies (NCS), and ultrasound. Ultrasound was conducted in bilateral median, ulnar, tibial, fibular, sural, and vagus nerves as well as cervical roots 5 and 6. Results were compared to age, sex, and body mass index matched healthy controls. RESULTS: A total of 320 nerves from 20 patients and 480 nerves from 30 controls were evaluated. NfL was significantly elevated in those with leprosy with a mean and standard deviation of 7.50 + 2.83 compared with 3.42 + 1.18 in controls (P < .001). Ultrasound showed focal enlargement of the nerves, particularly at entrapment sites. Additionally, there were noticeable changes in neural Doppler signal, echogenicity, and epineural thickness among the measured nerve sites. NfL levels in those with leprosy correlated closely with nerve cross-sectional area at all sites (P < .05). Functional and clinical assessment scores correlated with NfL and sonographic cross-sectional area as well (P ≤ .05). CONCLUSIONS: NfL is elevated in leprotic neuropathy. Ultrasound showed specific morphological changes in individuals with leprosy, and nerve enlargement correlated with NfL levels. Thus, both modalities may be useful for the diagnosis, prognosis, and disease monitoring in those with leprotic neuropathy, and further investigations are warranted.

Neuromuscular ultrasound in leprosy: A scanning protocol.

The diagnosis of leprosy neuropathies has been traditionally based on clinical findings and electrodiagnostic studies, but ultrasound has emerged as a new tool for use in clinical practice. We conducted a literature search on the subject and developed a pragmatic ultrasound scanning protocol for patients with confirmed or suspected leprosy neuropathy. We suggest scanning the ulnar, median, superficial radial, common fibular and sural nerves at specific sites and assessing cross-sectional area, vascularity, and epineural thickness. Our protocol is potentially useful in differentiating leprosy neuropathies from other demyelinating neuropathies, but its applicability and accuracy must be evaluated in different centers.

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).

Virtual neuromuscular ultrasound courses during COVID-19 pandemic: Leveraging technology to enhance learning opportunities.

INTRODUCTION/AIMS: Hands-on supervised training is essential for learning diagnostic ultrasound. Unfortunately, the coronavirus disease 2019 (COVID-19) pandemic led to suspension of in-person training courses. As a result, many hands-on training courses were converted into virtual courses during the pandemic. Several reports regarding virtual ultrasound courses exist, but none has addressed virtual neuromuscular ultrasound courses, their design, or participants' views of this form of training. Therefore, the aims of this study were: (1) to determine the feasibility of conducting virtual neuromuscular ultrasound courses during the COVID-19 pandemic; and (2) to report the positive and negative aspects of the courses through the analyses of the responses of post-course surveys. METHODS: Two virtual neuromuscular ultrasound courses, basic and intermediate level, were conducted by the Egyptian Neuromuscular Ultrasound society during August 2020. Post-course, the attendees were directed to an electronic survey that consisted of eight questions. Ninety-three responses (23.8%) were obtained from the survey of the basic course and 156 responses (44.4%) were obtained from the survey of the intermediate course. RESULTS: Ninety-eight percent of the respondents to basic course surveys, and 100% of the respondents to the intermediate course survey found the courses useful or very useful. DISCUSSION: This report demonstrates the utility of virtual neuromuscular ultrasound courses for those participants willing to respond to a survey and describes a proposed design for such courses. Although hands-on supervised ultrasound training is ideal, virtual courses can be useful alternatives to in-person training when in-person interaction is restricted.

Selecting disease-modifying medications in 5q spinal muscular atrophy.

Spinal muscular atrophy (SMA) is an inherited lower motor neuron disease. SMA occurs secondary to alterations in the survival motor neuron 1 gene (SMN1), which is the main driver of SMN protein production. The severity of the disease is determined by the number of copies of the SMN2 gene, which is a homolog to SMN1 but not as efficient in protein production. Three medications have recently been approved for the treatment of SMA. Nusinersen is an intrathecal antisense oligonucleotide that alters SMN2 pre-mRNA, onasemnogene abeparvovec-xioi is an intravenous SMN1 gene replacement therapy, and risdiplam is an oral small molecule splicing modifier of SMN2. No head-to-head studies have been conducted comparing these medications, so selection of one of these medications for an individual with SMA can be challenging. In this article we outline the efficacy, safety, and other pertinent factors to consider when selecting a therapy for an individual with SMA. The age of the individual and comorbidities, such as liver or kidney disease, help guide treatment choices. All three of these medications are efficacious, and early initiation is critical for obtaining the best outcomes.

Combination therapy with onasemnogene and risdiplam in spinal muscular atrophy type 1.

INTRODUCTION/AIMS: There are currently three medications approved for spinal muscular atrophy (SMA), but the use of these medications in combination has not been well described. METHODS: This is a retrospective report of four cases of SMA treated with dual onasemnogene and risdiplam therapy at our institution. RESULTS: Following onasemnogene therapy, all four patients experienced a perceived plateau of therapeutic benefit, at which time daily risdiplam was started. Transient fatigue and weakness was seen in two patients following risdiplam initiation, but this resolved within 1 mo. One patient was hospitalized with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and post-viral pneumonia, weeks following risdiplam initiation. No other adverse effects related to onasemnogene and risdiplam combination therapy were identified and all patients experienced objective and subjective improvement. DISCUSSION: Combination therapy with onasemnogene and risdiplam in patients with SMA appears to be well-tolerated. Further large prospective trials are needed to determine whether dual therapy is more efficacious than monotherapy, and to identify rare adverse events that may occur with the use of combination therapy.

Managing uncommon and unexpected findings during neuromuscular ultrasound.

One barrier to widespread adoption of neuromuscular ultrasound by clinical neurophysiologists is concern over how to identify and manage non-neuromuscular findings. This review addresses this concern by describing the sonographic appearance of a variety of commonly observed pathologies and anatomic variants in dermal, subcutaneous, bony, glandular, lymphatic, vascular, and other superficial tissues. Additionally, it outlines techniques to ensure proper clinical and ultrasound evaluation of unexpected or uncommon findings. Finally, it highlights strategies to manage unexpected findings, including how to best communicate findings to patients and referring clinicians to avoid unnecessary testing and ensure appropriate follow-up. Ultrasound extends the ability of the neuromuscular sonographer-clinician to contribute to patient care.

Neuromuscular ultrasound competency assessment: Consensus-based survey.

Neuromuscular ultrasound is a rapidly evolving specialty with direct application for patient care. Competency assessment is an essential standard needed to ensure quality for practitioners, particularly for those newly acquiring skills with the technique. Our aim was to survey experts' opinions regarding physician competency assessment of neuromuscular ultrasound and to identify minimal competency of knowledge and skills. The opinions of 18 experts were obtained through the Delphi method using two consecutive electronic surveys. A high degree of consensus was achieved on items regarding framework and the conduct of neuromuscular ultrasound assessment and the knowledge and skills that a candidate needs to attain minimal competency in neuromuscular ultrasound. In this study, a group of neuromuscular ultrasound experts developed a general framework for neuromuscular ultrasound competency assessment and recommended testable areas of knowledge and skills suitable for establishing minimal competency.