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.

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.

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).

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.

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.

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.

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.

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.

The future of ASET and electroneurodiagnostic technology.

The electroneurodiagnostics of the future will unfold from key factors that contribute to the growth and maturation of specialized diagnostic technologies in health care. Our unique business portfolio is the collection of services that make up electroneurodiagnostic technology. More than 100 years after Hans Berger first described EEG, electroencephalography may recapture the attention and imagination of research fourfold. And the attention that our profession directs toward education, professional growth, utilization of the technology, relating to the transdisciplinary team, and research will be our stake in the ground to become the pre-eminent diagnostic technology in the future. There is clear strategic direction for the American Society of Electroneurodiagnostic Technologists, Inc. (ASET) because the society is fundamentally interlaced with the architecture of electroneurodiagnostic technology and neuroscience.

Kathleen Mears Memorial Lecture: innovative research for the END allied healthcare professional.

Electroneurodiagnostic technologists play a key role in health care. It is time for these allied health professionals to make a commitment and contribution, using scientific methodology, to the body of medical research and publication. Research methods, quantitative, qualitative, and mixed research design will be reviewed. Introduced is an innovative research approach that is applicable to END practice; it is called, action research.

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.

Has electrical growth cone guidance found its potential?

Many neurobiologists spurn the existence and use of direct-current (DC) electric fields (EFs) in nervous system development and regeneration. This is despite direct measurement of EFs in embryos and adults, and evidence that EFs are required for normal development, dramatically influence the rate and direction of nerve growth in vitro, and promote nerve regeneration in vivo. The notion that growth cones use EFs as guidance cues was dismissed partly because there was no convincing evidence that naturally occurring EFs influence nerve growth at the single-cell level in vivo. Recent work indicates that growth cones can be guided by EFs in vivo and, intriguingly, that in vitro guidance by chemotropic gradients and EFs might invoke similar mechanisms. Ongoing clinical trials to assess the effectiveness of DC EFs in promoting the regeneration of human spinal cord could allow EFs to achieve their potential.

Assessment of cardiovascular autonomic function.

Autonomic assessment has played an important role in elucidating the role of the autonomic nervous system in diverse clinical and research settings. The techniques most widely used in the clinical setting entail the measurement of an end-organ response to a physiological provocation. The non-invasive measures of cardiovascular parasympathetic function involve the analysis of heart rate variability while the measures of cardiovascular sympathetic function assess the blood pressure response to physiological stimuli. Prolonged tilt-table testing, with or without pharmacological provocation, has become an important tool in the investigation of a predisposition to neurally mediated (vasovagal) syncope. Frequency domain analyses of heart rate and blood pressure variability, microneurography, occlusion plethysmography, laser Doppler imaging and flowmetry, and cardiac sympathetic imaging are currently research tools but may find a place in the clinical assessment of autonomic function in the future.

The use of electropalatography in the assessment and treatment of acquired motor speech disorders in adults: current knowledge and future directions.

Electropalatography (EPG) has been employed to measure speech articulation since the mid-1970s. This technique has predominately been used in experimental phonetic research and in the diagnosis and treatment of articulation disorders in children. However, there is a growing body of research employing EPG to diagnose and treat articulatory impairment associated with acquired motor speech disorder (MSD) in adults. The purpose of this paper was to (1) review the findings of studies pertaining to the assessment and treatment of MSDs in adults using EPG, (2) highlight current methodologies employed, and (3) discuss the potential limitations of EPG in the assessment and treatment of MSDs and examine directions for future applied research and treatment studies.

Electroneurodiagnostics--for the joy of it!

During the middle of the last century, discoveries about the brain and the nervous system gave birth to a new technology. Thanks to the pioneers in those efforts, the early EEG technicians, and our efforts through the years, the technology has grown, expanded, and become amazingly sophisticated. This is about loving what we do, and finding joy and satisfaction in our accomplishments. We make health care better. We improve the quality of people's lives. We prompt physicians to sit up and take notice because we complement their efforts at diagnosing, monitoring, and treating people's neurologic illnesses. We're old enough to have a history, and a story...about Kathy Mears and hundreds of dedicated technologists, many of whom sprouted from those first small groups trained by the Fathers of EEG to give them important scientific data. And here we are, fifty-some years later, several thousand strong, influenced by things those first technicians never dreamed about! We're still producing data, but things have changed. Let's examine the challenges electroneurodiagnostic (END) technologists encounter in the current healthcare arena, and focus on what we need to find joy and fulfillment in our important work. Come celebrate our profession. Come share the joy!

Clinical cardiac electrophysiology: history, rationale, and future.

The discipline of clinical cardiac electrophysiology has evolved over the past 40 years. Intense interest has resulted in the clinical application of intracardiac electrophysiologic techniques over the past 20 years. Clinical cardiac electrophysiologic studies have developed since the demonstration that programmed electrical stimulation could be performed in the human heart to evaluate tachyarrhythmias and that cardiac electrical activity that could not be detected on the body surface could be measured with intracardiac electrodes. Clinical electrophysiologic techniques have evolved for the assessment of sinus nodal, AV nodal, and His-Purkinje system function. The evaluation of tachyarrhythmias has progressed rapidly, and pharmacologic, device, and surgical therapy can now be guided by electrophysiologic studies. Invasive electrophysiologic studies have confirmed the utility of noninvasive electrocardiographic analysis and in several circumstances have proved that invasive studies are not necessary. Alternatives to invasive electrophysiologic evaluation continue to be debated. It is clear that when performed by well-trained individuals in appropriately equipped laboratories, electrophysiologic studies are safe and can be shown to be beneficial. Clinical cardiac electrophysiology continues to evolve, and problems of uniformity of methods, definitions of terms, and protocols remain to be resolved. The future of clinical cardiac electrophysiology appears to be one of continued evolution of techniques, refinement of indications, and continued clinical applications.

Electropotential evaluation as a new technique for diagnosing breast lesions.

A new approach, termed the Biofield test, may have the potential to augment the process of diagnosing breast cancer. This technique is based on the analysis of skin surface electrical potentials measured by an array of specially designed sensors which are placed on the breasts. Measurements are recorded noninvasively and then analyzed using pattern recognition algorithms to produce an immediate and objective assessment of breast tissue in vivo. Initial clinical trials suggests that the test can achieve a sensitivity of approximately 90% and a specificity of 40-50%, which indicates that the test might be useful for excluding cancer when it is, in fact, absent. Although research to date has focused on the differential diagnosis of suspicious breast lesions, future applications could include breast cancer screening, close surveillance and diagnosis of recurrent cancers in breasts previously treated with conservative therapy, and monitoring the effectiveness of breast cancer therapies. Improvements and new applications are expected to occur as additional research and validation in actual clinical settings is performed.

The changing role of pediatric electrodiagnosis.

Electrodiagnosis is one of several useful diagnostic tests in infants and children who have anterior horn cell disease, neuropathy, neuromuscular junction disorders, or myopathy. It is also used for intraoperative monitoring in children. For hypotonic infants and for older children with a nonspecific presentation of weakness, EDX may provide direction for more specific diagnostic testing, such as DNA testing with or without muscle biopsy. Genetic testing has an increasingly important role in the diagnosis of children with neuromuscular disorders. Future improvements in motor unit quantitation, which do not require active patient cooperation and require less time than current methodologies, may make EDX more specific and useful for diagnosing neuromuscular disease in children.

New directions in cardiovascular mapping and therapy.

Cardiovascular mapping has allowed us to fully understand the mechanisms of some of the cardiac arrhythmias and enabled us to devise new therapeutic options for them. Endocardial mapping by electrophysiological studies using three to four endocardial catheters introduced via the vein or artery to the heart allows us to directly map the electrical activity of the heart during sinus rhythm and during abnormal tachyarrhythmias. The simultaneous recording of electrical activity from the surface electrocardiogram, right ventricular apex, His bundle, high right atrium, coronary sinus, with or without a roving mapping catheter, enables us to precisely map the electrical activation sequence in the heart. This technique has been especially useful for mapping supraventricular tachycardias and the precise mapping of the accessory pathway or slow pathway potentials have now allowed us to selectively ablate them using radiofrequency energy delivered via the tip of the endocardial catheter. Intraoperative direct cardiac mapping has allowed us to reconfirm the findings of endocardial catheter mapping immediately prior to surgery. The intraoperative mapping is more precise and allows direct visualisation of the abnormal site for the surgeon to operate. Computerised mapping using multichannel recordings has facilitated mapping of the abnormal site for patients with haemodynamically unstable or nonsustained ventricular tachycardia, and thus allows the surgeon to perform surgical resection or cryoablation of the abnormal site. Cardiovascular mapping has thus enabled us not only to understand the mechanisms of cardiac arrhythmias but allows us to provide curative therapy for patients who are at risk from sudden arrhythmic death or otherwise need life long drug therapy.