Safety and pain in electrodiagnostic studies

Discomfort is an unavoidable part of electrodiagnostic (EDX) studies. The most readily modifiable mediator of electromyography (EMG)‐associated pain is muscle selection. Interventions that may reduce pain include vapocoolant spray, ibuprofen, and techniques such as slapping or stretching the skin. Needlestick injuries to health care workers carry the risk of transmitting bloodborne illnesses, but other infectious complications of EDX studies are very rare. EMG probably contributes to asymptomatic hemorrhage in approximately 1% of patients, but clinically significant bleeding has only been reported a few times. Therapeutic anticoagulation does not significantly increase this risk. With standard procedures, there have been no reports of patients developing cardiac arrhythmia from nerve conduction studies. No special precautions are necessary in patients with implantable cardiac devices or intravenous lines. There is a small risk of pneumothorax associated with EMG of the diaphragm and chest wall muscles. Several techniques have been suggested to improve the safety of diaphragm EMG. Muscle Nerve 55: 149–159, 2017Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/136014/1/mus25421_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/136014/2/mus25421.pd

Does cerebrospinal fluid analysis have a meaningful role in the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy?

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150522/1/mus26513.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150522/2/mus26513_am.pd

Nerve conduction studies are safe in patients with central venous catheters

IntroductionIt is unknown if central venous catheters bypass the skin’s electrical resistance and engender a risk of nerve conduction study‐induced cardiac arrhythmia. The objective of this study is to determine if nerve conduction studies affect cardiac conduction and rhythm in patients with central venous catheters.MethodsUnder continuous 12‐lead electrocardiogram monitoring, subjects with and without central venous catheters underwent a series of upper extremity nerve conduction studies. A cardiologist reviewed the electrocardiogram tracings for evidence of cardiac conduction abnormality or arrhythmia.ResultsTen control subjects and 10 subjects with central venous catheters underwent the nerve conduction study protocol. No malignant arrhythmias or conduction abnormalities were noted in either group.ConclusionsNerve conduction studies of the upper extremities, including both proximal stimulation and repetitive stimulation, do not appear to confer increased risk of cardiac conduction abnormality in those patients with central venous catheters who are not critically ill or have a prior history of arrhythmia. Muscle Nerve 56: 321–323, 2017Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137740/1/mus25497.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137740/2/mus25497_am.pd

Bilateral nerve conduction studies in the evaluation of distal symmetric polyneuropathy

IntroductionNerve conduction studies are used to aid in the diagnosis of distal symmetric polyneuropathy (DSP). It is unclear whether bilateral lower extremity nerve conduction studies (NCS) are needed when evaluating for suspected DSP.MethodsWe retrospectively analyzed NCS from patients who presented to the University of Michigan electromyography laboratory between July 1, 2016 and December 31, 2017 with symptoms of DSP to assess agreement and correlation between left and right lower extremity NCS parameters.ResultsWe found significant agreement between abnormalities in individual nerve parameters of the left and right lower extremities of 105 patients, most notably in the sural nerve. In the 53 patients with bilateral sural, peroneal, and tibial studies, there was also significant agreement between whether the left and right met electrodiagnostic criteria for DSP (κ = 0.77).DiscussionBilateral lower extremity NCS may have limited utility in the evaluation of suspected DSP. Muscle Nerve, 2019Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151276/1/mus26616.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151276/2/mus26616_am.pd

Electromyography‐related pain: Muscle selection is the key modifiable study characteristic

Introduction : The aim of this study was to estimate the effects of patient, provider, and study characteristics on electromyography (EMG)‐related pain. Methods : Patients undergoing EMG rated their EMG‐related pain after each muscle was studied on a 100‐point visual analog scale (VAS). Investigators recorded the order in which the muscles were sampled, the total time spent with the needle in each muscle, and whether electrical endplate noise was noted. Results : A total of 1781 muscles were studied in 304 patients. Eleven muscles were associated with significantly more or less pain than the others. Endplate noise was associated with more pain (5.4 mm, 95% CI 2.8–7.0). There was a small, but significant effect from needling time (0.02 mm, 95% CI 0.00–0.04). Conclusions : Among factors that electromyographers can control, muscle selection has the greatest impact on pain. Our data include an extensive list of muscle‐specific EMG‐related pain scores. Provider and other study characteristics have little or no impact on EMG‐related pain. Muscle Nerve 49:570–574, 2014Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106736/1/mus23974.pd

Multi-ethnic genome-wide association study for atrial fibrillation

Atrial fibrillation (AF) affects more than 33 million individuals worldwide and has a complex heritability. We conducted the largest meta-analysis of genome-wide association studies (GWAS) for AF to date, consisting of more than half a million individuals, including 65,446 with AF. In total, we identified 97 loci significantly associated with AF, including 67 that were novel in a combined-ancestry analysis, and 3 that were novel in a European-specific analysis. We sought to identify AF-associated genes at the GWAS loci by performing RNA-sequencing and expression quantitative trait locus analyses in 101 left atrial samples, the most relevant tissue for AF. We also performed transcriptome-wide analyses that identified 57 AF-associated genes, 42 of which overlap with GWAS loci. The identified loci implicate genes enriched within cardiac developmental, electrophysiological, contractile and structural pathways. These results extend our understanding of the biological pathways underlying AF and may facilitate the development of therapeutics for AF

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Distal symmetric polyneuropathy phenotype in patients with sensory neuronopathy at the time of electrodiagnosis

Introduction/AimsIt is unknown how often patients with sensory neuronopathy (SNN) present with a distal symmetric polyneuropathy (DSP) phenotype. In these cases, electrodiagnostic testing may discriminate SNN with a DSP phenotype from DSP.MethodsWe reviewed the records of patients who met SNN diagnostic criteria between January 2000 and February 2021 and identified patients with a DSP phenotype at the time of electrodiagnosis.ResultsSixty‐two patients fulfilled SNN diagnostic criteria. At symptom onset, 20 (32.2%) patients presented with distal symmetric sensory symptoms limited to the feet. However, most progressed rapidly over 6 months or developed asymmetric symptoms. At the time of electrodiagnosis, only seven (11.3%) patients had a DSP phenotype. Of these seven patients, four had cerebellar ataxia with neuropathy and vestibular areflexia syndrome, one had vitamin B6 deficiency, one was thought to be alcohol‐induced, and one was idiopathic.DiscussionPatients with SNN rarely present with a DSP phenotype at the time of electrodiagnosis. The finding that one third of cases resemble DSP at onset highlights the importance of clinical monitoring. In patients with a DSP phenotype, the presence of ataxia at onset or significant progression within 6 months may suggest the possibility of SNN and should prompt additional investigations, such as electrodiagnosis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/172026/1/mus27488.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/172026/2/mus27488_am.pd

Patients who meet electrodiagnostic criteria for CIDP rarely present with a sensory predominant DSP phenotype

IntroductionIt is unknown how often patients with electrodiagnostic evidence of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), a potentially treatable condition, present with a distal symmetric polyneuropathy (DSP) phenotype.MethodsWe reviewed the records of patients who presented to our electrodiagnostic laboratory between January 1, 2011, to December 31, 2019, and fulfilled electrodiagnostic criteria for CIDP to identify those who presented with a sensory predominant DSP phenotype.ResultsOne hundred sixty‐two patients had a chronic acquired demyelinating neuropathy, of whom 138 met criteria for typical or atypical CIDP. Nine of these patients presented with a sensory predominant DSP phenotype, among whom six were eventually diagnosed with distal acquired demyelinating symmetric (DADS) neuropathy; one with Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal protein, Skin changes (POEMS) syndrome; and two with idiopathic DSP. The prevalence of acquired chronic demyelinating neuropathies among all patients presenting with a DSP phenotype was estimated to be 0.34%.DiscussionPatients who meet electrodiagnostic criteria for CIDP rarely present with a sensory predominant DSP phenotype, and electrodiagnostic testing rarely identifies treatable demyelinating neuropathies in patients who present with a DSP phenotype.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/167834/1/mus27235.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/167834/2/mus27235_am.pd

Patients who meet electrodiagnostic criteria for CIDP

IntroductionIt is unknown how often patients with electrodiagnostic evidence of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), a potentially treatable condition, present with a distal symmetric polyneuropathy (DSP) phenotype.MethodsWe reviewed the records of patients who presented to our electrodiagnostic laboratory between January 1, 2011, to December 31, 2019, and fulfilled electrodiagnostic criteria for CIDP to identify those who presented with a sensory predominant DSP phenotype.ResultsOne hundred sixty‐two patients had a chronic acquired demyelinating neuropathy, of whom 138 met criteria for typical or atypical CIDP. Nine of these patients presented with a sensory predominant DSP phenotype, among whom six were eventually diagnosed with distal acquired demyelinating symmetric (DADS) neuropathy; one with Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal protein, Skin changes (POEMS) syndrome; and two with idiopathic DSP. The prevalence of acquired chronic demyelinating neuropathies among all patients presenting with a DSP phenotype was estimated to be 0.34%.DiscussionPatients who meet electrodiagnostic criteria for CIDP rarely present with a sensory predominant DSP phenotype, and electrodiagnostic testing rarely identifies treatable demyelinating neuropathies in patients who present with a DSP phenotype.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/167834/1/mus27235.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/167834/2/mus27235_am.pd