Neurophysiological patterns of acute and post-acute foodborne botulism.

INTRODUCTION/AIMS: Neurophysiological patterns in patients with foodborne botulism are rarely described after the acute phase. We report data from a large Italian outbreak of botulism, with patients evaluated at different timepoints after poisoning. METHODS: Eighteen male patients (mean age 47 ± 8.4 y) underwent 22 clinical and neurophysiological evaluations (4 patients were re-evaluated). The resting compound muscle action potential (CMAP) amplitude, postexercise CMAP amplitude, CMAP change after high-frequency (50 Hz) repetitive nerve stimulation (HFRNS), and motor unit action potentials (MUAPs) were assessed in the acute (4-8 days after poisoning; 5 patients), early post-acute (32-39 days after poisoning; 5 patients), and late post-acute (66-80 days after poisoning; 12 patients) phases. RESULTS: In the acute, early post-acute, and late post-acute phases, respectively, reduced CMAP amplitudes were found in 100%, 20%, and 17% of patients; abnormal postexercise CMAP facilitation was observed in 100%, 40%, and 0% of patients; and pathological incremental responses to HFRNS were found in 80%, 50%, and 8% of patients. Baseline CMAP amplitudes, postexercise CMAP facilitation, and CMAP increases in response to HFRNS differed significantly between the acute and post-acute phases. Small MUAPs were found in 100% of patients in the acute and early post-acute phases and in 50% of patients in the late post-acute phase. DISCUSSION: The neurophysiological findings of foodborne botulism vary considerably according to the evaluation time point. In the post-acute phase, different neurophysiological techniques must be applied to support a diagnosis of botulism.

Optimizing the operation of an electrodiagnostic laboratory during the COVID-19 pandemic: A 6-month single-center experience.

INTRODUCTION/AIMS: The initial surge of the coronavirus disease-2019 (COVID-19) pandemic in early 2020 led to widespread cancellation of elective medical procedures in the United States, including nonurgent outpatient and inpatient electrodiagnostic (EDx) studies. As certain regions later showed a downtrend in daily new cases, EDx laboratories have reopened under the guidance of the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM). In our reopening experience guided by the AANEM, we measured relevant outcomes to determine further workflow adaptations. We aimed to detail our experience and share the lessons learned. METHODS: We reviewed the clinical volumes, billing data, diagnosis distributions, and rates of COVID-19 exposure and transmission among patients and staff in our EDx laboratory during the first 6 months of reopening, starting on June 1, 2020. For context, we detailed the recent AANEM guidelines we adopted at our laboratory, supplemented by other consensus statements. RESULTS: We completed 816 outpatient studies from June 1 to December 1, 2020, reaching 97% of the total volume and 97% of total billing compared with the same time period in 2019. The average relative value units per study were similar. There were no major shifts in diagnosis distributions. We completed 10 of 12 requested inpatient studies during this period. There were no known COVID-19 transmissions between patients and staff. DISCUSSION: Our experience suggests that it is possible to safely operate an EDx laboratory under the guidance of the AANEM and other experts, with clinical volume and billing rates comparable to pre-pandemic baselines.

Kathleen Mears Memorial Lecture: The View from Here - A Perspective on Neurodiagnostic Technology.

For over 14 years in my role as ASET's Director of Education, I have had the unique opportunity and privilege of communicating with many people every day, from across the country, to across the globe. The diverse range of people who called me with questions included Neurodiagnostic technologists, physicians, and those seeking advice to enter the field. This article includes a reflection on the many questions asked, and most pressing concerns shared with me. Based on the "top ten" questions asked by callers, I determined the key trends and concerns related to the practice of Neurodiagnostic Technology. Key workforce issues and supporting data are included. I also provide suggestions for resources that can be used to address those questions. When contemplating the overall message that became apparent when I reviewed the many years of conversations I had, I find that there are many uplifting and inspirational thoughts to be shared.

AANEM survey of training in electrodiagnostic medicine in U.S. residency programs.

BACKGROUND: Little literature exists describing resident training in peripheral electrodiagnosis (EDX). METHODS: U.S. residency programs in neurology and physical medicine and rehabilitation (PM&R) were surveyed by the AANEM (American Association of Neuromuscular and Electrodiagnostic Medicine) on specific features of EDX training. RESULTS: Ninety-seven programs responded to the survey. Training duration was 4-8 weeks in most neurology programs; training averaged 22 weeks in PM&R programs. EDX experience was required in all PM&R and in 90% of neurology programs. Results varied greatly for the residency years of training, pulling of residents for other responsibilities, participation in continuity clinics, number of teaching physicians, number of needle examinations performed, organization of nerve conduction training, written/oral examinations, muscle/nerve biopsy reviews, and training materials. CONCLUSIONS: This survey demonstrated large variability in training of neurology and PM&R residents in peripheral EDX.

Electroglottography - An Update.

Electroglottography (EGG) is a low-cost, noninvasive technology for measuring changes of relative vocal fold contact area during laryngeal voice production. EGG was introduced about 60 years ago and has gone through a "golden era" of increased scientific attention in the late 1980s and early 90s. During that period, four eminent review papers were written. Here, an update to these reviews is given, recapitulating some earlier landmark contributions and documenting noteworthy developments during the past 25 years. After presenting an algorithmic bibliographic analysis, some methodological aspects pertaining to measurement technology, qualitative and quantitative analysis, and respective interpretation are discussed. In particular, the interpretation of landmarks in the (first derivative of the) EGG waveform is critically examined. It is argued that because of inferior-superior and anterior-posterior phase differences of vocal fold vibration, vocal fold (de)contacting does not occur instantaneously, but over an interval of time. For this reason, instants of vocal fold closing and opening cannot be resolved exactly from the EGG signal. Consequently, any quantitative analysis parameter relying on the determination of (de)contacting events (such as the EGG contact quotient) should be interpreted with care. Finally, recent developments are reviewed for the various fields of application of EGG, including basic voice science and voice production physiology, speech signal processing and classification, clinical practice including swallowing, phonetics, hearing sciences, psychology, singing, trumpet playing, and mammalian and avian bioacoustics. Overall, EGG has over the past six decades developed into a mature technology with a wide range of applications. However, due to current limitations, the full potential of the methodology has as yet not been fully exploited. Future development may occur on three levels: (a) rigorous validation of existent measurement approaches; (b) introduction and rigorous validation of novel quantitative and interpretative approaches; and (c) advancement of the measurement technology itself.

A new methodology to record from human primary afferents provides insight for somatosensory neuroprosthetics.

Muscle spindles are integral to proprioception and their behavior is of particular interest for the design of somatosensory neuroprostheses. Prior knowledge about human muscle spindles has been limited to microneurography recordings in peripheral nerves using joint movements that do not disrupt the electrode. Recent studies demonstrate a new methodology for studying the afferent encoding of proprioception during freestanding, providing important information for neural engineering and the broader scientific community (Knellwolf TP, Burton AR, Hammam E, Macefield VG. J Neurophysiol 120: 953-959, 2018; Knellwolf TP, Burton AR, Hammam E, Macefield VG. J Neurophysiol 121: 74-84, 2019; Macefield VG, Knellwolf TP. J Neurophysiol 120: 452-467, 2018).

Aplicação da técnica de eletrodiagnóstico em pacientes críticos: uma revisão sistemática / Application of electrodiagnostic technique in critically ill patients: a systematic review

O ambiente de terapia intensiva está evoluindo em tecnologias para avaliação e tratamento sendo uma das técnicas mais atuais aplicadas neste ambiente o eletrodiagnóstico. Esta é uma revisão sistemática desenvolvida com base nos resultados de pesquisa das principais bases de dados, seguindo o PRISMA. Neste foram incluídos somente artigos observacionais que utilizaram a técnica de eletrodiagnóstico em pacientes críticos, para os mais diferentes objetivos e desfechos. As bases de dados consultadas foram: MEDLINE (acessado via PubMed), Fisioterapia Evidence banco de dados (Pedro), Registro de Ensaios Controlados (CENTRAL Cochrane) e EMBASE além de uma busca manual de referências adicionais. Um total de 10 artigos foram encontrados, sendo que dois apresentaram-se repetidos e outros seis foram excluídos por não contemplarem os critérios de inclusão obtendo-se ao final um total de dois artigos totalizando 33 pacientes. Um dos artigos apresentou resultados seguros, sem lesão muscular e o protocolo foi viável para ser aplicado em terapia intensiva. O outro artigo que após lesão cerebral traumática os pacientes podem apresentar distúrbios eletrofisiológicos, além de atrofia muscular generalizada sendo evidenciados pela técnica de eletrodiagnóstico. (AU)

The intensive care environment is evolving in technologies for evaluation and treatment, and these include a recent technique named electrodiagnosis. This systematic review was based on search results from major databases, following PRISMA guidelines. Only observational studies using the electrodiagnostic technique in critically patients for different objectives and outcomes were included. The following databases were searched: MEDLINE (accessed via PubMed), Physiotherapy Evidence database (Pedro), Controlled Trials Registry (CENTRAL Cochrane) and EMBASE, in addition to a manual search for additional references. Ten articles were found, two of which were repeated and six were excluded because they did not meet the inclusion criteria; thus, two articles were selected, with a total of 33 patients. One of the articles showed safe results, without any muscle injury, and the protocol was applicable in intensive care. The other article demonstrated that, after traumatic brain injury, patients may present with electrophysiological disorders and generalized muscle atrophy, which can be revealed by the electrodiagnostic technique. (AU)

Prognostic value of clinical and electrodiagnostic parameters at time of diagnosis in patients with amyotrophic lateral sclerosis.

OBJECTIVE: To assess the added prognostic value of the aggregated clinical and electrodiagnostic data, which define a given diagnostic category according to the Awaji or revised El Escorial criteria at time of diagnosis in patients with amyotrophic lateral sclerosis (ALS). METHODS: Clinical signs and electrodiagnostic test results were collected at time of diagnosis in 396 patients with ALS between January 2009 and January 2016. Significant predictors of prognosis were identified using a univariate model, and later combined in a multivariate Cox regression model. RESULTS: Known factors associated with reduced survival included older age at onset, shorter diagnostic delay, higher ALSFRS-R slope and presence of C9orf72 mutation (all p < 0.05). Diagnostic category according to Awaji (p < 0.0001) or to revised El Escorial (p = 0.0177) criteria, definite ALS according to Awaji (p < 0.0001) or to revised El Escorial (p = 0.0343) and number of regions with LMN involvement (p < 0.0001) were all associated with shorter survival. DISCUSSION: Clinical and electrodiagnostic data at time of diagnosis provide additional prognostic information compared to other known prognostic factors. Diagnostic category according to Awaji and the extensiveness of LMN involvement contain the most additional value.

The value transformation of health care: Impact on neuromuscular and electrodiagnostic medicine.

Beginning in 2017, most physicians who participate in Medicare are subject to the Medicare Access and CHIP Reauthorization Act (MACRA), the milestone legislation that signals the US health care system's transition from volume-based to value-based care. Here we review emerging trends in development of value-based healthcare systems in the US. MACRA and the resulting Quality Payment Program create 2 participation pathways, the Merit-based Incentive Payment System (MIPS) and the Advanced Alternative Payment Model (AAPM) pathway. Although there are several program incentives for AAPM participation, to date there have been few AAPM options for specialists. MIPS and its widening bonus and penalty window will likely be the primary participation pathway in the early years of the program. Value-based payment has the potential to reshape health care delivery in the United States, with implications for neuromuscular and electrodiagnostic (EDX) specialists. Meaningful quality measures are required for neuromuscular and EDX specialists. Muscle Nerve 56: 679-683, 2017.

The electrodiagnostic natural history of parsonage-turner syndrome.

INTRODUCTION: Recovery from Parsonage-Turner syndrome (PTS) is generally favorable, although recovery times have been shown to vary, in part because there are no universally accepted outcome measures. In this study, we describe the electrodiagnostic natural history of this condition based on objective electrodiagnostic testing, and propose that complete electrodiagnostic recovery can be seen as early as 1 year. METHODS: Twenty-six subjects with 29 affected nerves confirmed as PTS were followed every 3 months for electrodiagnostic testing, or until full reinnervation was confirmed. RESULTS: Twenty-three cases (79.3%) demonstrated electrodiagnostic evidence of initial recovery at a mean of 5.8 months. Nine cases (31%) showed complete electrodiagnostic recovery at a mean of 1 year. When excluding cases with <1 year of follow-up, 52.9% achieved complete electrodiagnostic recovery. CONCLUSIONS: In contrast to previous reports, full electrodiagnostic recovery of PTS was demonstrated at a mean of 1 year in > 50% of patients with longer term follow-up. Muscle Nerve 56: 737-743, 2017.

Emerging techniques in the electrodiagnostic laboratory.

Electrodiagnostic techniques have been used for many decades to study neuromuscular diseases. In recent years, we have seen the extension of these methods to study disease progression, complemented by other technologies, for example, ultrasonography. There also is a growing interest in using surface electromyography, which is generally better accepted by patients than needle insertions. This article will discuss these trends and give examples of a few new and emerging methods that have the potential for use in an electrodiagnostic laboratory.

Current trends in pedicle screw stimulation techniques: lumbosacral, thoracic, and cervical levels.

Unequivocally, pedicle screw instrumentation has evolved as a primary construct for the treatment of both common and complex spinal disorders. However an inevitable and potentially major complication associated with this type of surgery is misplacement of a pedicle screw(s) which may result in neural and vascular complications, as well as impair the biomechanical stability of the spinal instrumentation resulting in loss of fixation. In light of these potential surgical complications, critical reviews of outcome data for treatment of chronic, low-back pain using pedicle screw instrumentation concluded that "pedicle screw fixation improves radiographically demonstrated fusion rates;" however the expense and complication rates for such constructs are considerable in light of the clinical benefit (Resnick et al. 2005a). Currently, neuromonitoring using free-run and evoked (triggered) electromyography (EMG) is widely used and advocated for safer and more accurate placement of pedicle screws during open instrumentation procedures, and more recently, guiding percutaneous placement (minimally invasive) where the pedicle cannot be easily inspected visually. The latter technique, evoked or triggered EMG when applied to pedicle screw instrumentation surgeries, has been referred to as the pedicle screw stimulation technique. As concluded in the Position Statement by the American Society of Neurophysiological Monitoring (ASNM), multimodality neuromonitoring using free-run EMG and the pedicle screw stimulation technique was considered a practice option and not yet a standard of care (Leppanen 2005). Subsequently, the American Association of Neurological Surgeons/Congress of Neurological Surgeons (AANS/CNS) Joint Section on Disorders of the Spine and Peripheral Nerves published their "Guidelines for the Performance of Fusion Procedures for Degenerative Disease of the Lumbar Spine" (Heary 2005, Resnick et al. 2005a, Resnick et al. 2005b). It was concluded that the "primary justification" of intraoperative neuromonitoring"... is the perception that the safety and efficacy of pedicle screw fixation are enhanced..." (Resnick et al. 2005b). However in summarizing a massive (over 1000 papers taken from the National Library of Medicine), contemporary, literature review spanning nearly a decade (1996 to 2003), this invited panel (Resnick et al. 2005b) recognized that the evidence-based documents contributing to the parts related to pedicle screw fixation and neuromonitoring were "... full of potential sources of error ..." and lacked appropriate, randomized, prospective studies for formulating rigid standards and guidelines. Nevertheless, current trends support the routine use and clinical utility of these neuromonitoring techniques. In particular free-run and triggered EMG have been well recognized in numerous publications for improving both the accuracy and safety of pedicle screw implantation. Currently, treatment with pedicle screw instrumentation routinely involves all levels of the spine - lumbosacral, thoracic, and cervical. Significant historical events, various neuromonitoring modalities, intraoperative alarm criteria, clinical efficacy, current trends, and caveats related to pedicle screw stimulation along the entire vertebral column will be reviewed.

Advances in the treatment of chronic inflammatory demyelinating neuropathies in 2010.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an uncommon disease of the peripheral nerves. The diagnosis is based mainly on clinical presentation, cerebrospinal fluid (CSF) examination, and electrodiagnostic studies. Treatment of CIDP has at least two components: supportive care and specific therapy including primarily steroids, intravenous immunoglobulins (IVIg), and plasmapheresis (PE). This review summarizes progress in the treatment of CIDP published during the last year.

Developing reference data for nerve conduction studies: an application of quantile regression.

INTRODUCTION: The interpretation of nerve conduction studies, as with any diagnostic test, requires an ability to differentiate normal from abnormal. To this end there have been many efforts to establish reference or normative data, but they have been hampered by a variety of methodological shortcomings. The goal of this article is to introduce a statistical method known as quantile regression, which we contend is better suited than existing methods to generate reference data, especially when there is a need to adjust for covariates. METHODS: Statistical methods previously used for generation of reference data are reviewed. Quantile regression is presented and used to estimate the lower percentiles for response amplitudes of the radial sensory and tibial motor nerves. RESULTS: Using data from 190 subjects, it is possible to estimate as low as the 2nd percentile for the radial nerve. Using data from 99 subjects it is possible to estimate as low as the 4th percentile for the tibial nerve. Percentile estimation for both nerves required adjustment for age, but no other covariates. DISCUSSION: Quantile regression is well suited to the estimation of extreme percentiles, the very percentiles that are most relevant to reference data. It is also less dependent on data distribution and permits covariate adjustment, even for continuous variables such as age, which are clinically important determinants of reference data for nerve conduction studies. We recommend the use of quantile regression for future studies of reference data.

Meralgia parestésica: a propósito de una serie de 140 casos / Meralgia Paraesthetca: a report on a series of 140 cases

Introducción. La meralgia parestésica es una patología frecuente en la consulta de neurología extrahospitalaria. Apesar de ello, el diagnóstico, tratamiento y pronóstico de este cuadro no están bien establecidos. Pacientes y métodos. Estudioretrospectivo de 140 pacientes. Se recogen datos demográficos, clínica, estudio diagnóstico, etiología, tratamiento y evolución.Resultados. Hubo un predominio masculino, con una mediana de 54 años. El seguimiento medio fue de 25 meses. Lossíntomas narrados fueron: acorchamiento, dolor urente, hormigueo o pinchazos en el territorio nervioso. En la exploración sehalló hipoestesia como signo más frecuente. Hubo historia de otra neuropatía compresiva en el 13,6%. El diagnóstico se basóen la historia clínica y la exploración neurológica. El estudio neurofisiológico y las pruebas complementarias se reservaronpara casos atípicos. La etiología más frecuente fue la espontánea, y se hallaron sólo tres casos secundarios a lesión estructural.Un tercio de los pacientes recibió tratamiento farmacológico. Aunque el cuadro fue benigno, en la mayoría tendióa cronificarse. Los pacientes tratados farmacológicamente no mostraron una mejoría significativa frente a los que no recibierontratamiento. El dato pronóstico más importante para la mejoría del cuadro fue la identificación y corrección de los factoresdesencadenantes de compresión del nervio. Conclusiones. La meralgia parestésica es una patología frecuente, benigna,pero con tendencia a cronificarse, en la que es importante identificar y corregir factores mecánicos, con pobre respuesta altratamiento farmacológico, y sólo en casos excepcionales secundaria a lesión estructural (AU)

Introduction. Meralgia paraesthetica is a pathology that is frequently seen in visits to extra-hospital neurologyservices. Nevertheless, the diagnosis, treatment and prognosis of this condition remain somewhat unclear. Patients andmethods. A retrospective study was conducted involving 140 patients. Data were collected concerning demographic aspects,clinical picture, diagnostic study, aetiology, treatment and progression. Results. There was a predominance of males, with amean age of 54 years. The mean follow-up time was 25 months. The symptoms that were reported were as follows: numbness,burning pain, tingling or prickling in the nerve territory. Hypaesthesia was the most frequent sign found in the examination.History of another compressive neuropathy was present in 13.6% of patients. The diagnosis was based on the patient recordand the neurological examination. The neurophysiological study and complementary tests were reserved for atypical cases. Themost common causation was spontaneous and only three cases were found to be secondary to a structural lesion. A third of thepatients were receiving pharmacological treatment. Although the clinical picture was benign, in most cases it tended to becomechronic. Patients treated pharmacologically did not show a significant improvement in comparison to those who were not giventreatment. The most important data for forecasting improvement of the clinical picture were the identification and correction ofthe factors precipitating compression of the nerve. Conclusions. Meralgia paraesthetica is a frequent, benign pathology butwith a tendency to become chronic that responds poorly to pharmacological treatment. It is important to identify and correctmechanical factors and only in exceptional cases is it secondary to a structural lesion. (AU)