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1.
PLoS Comput Biol ; 15(10): e1007004, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31622338

RESUMO

With the advent of advanced MRI techniques it has become possible to study axonal white matter non-invasively and in great detail. Measuring the various parameters of the long-range connections of the brain opens up the possibility to build and refine detailed models of large-scale neuronal activity. One particular challenge is to find a mathematical description of action potential propagation that is sufficiently simple, yet still biologically plausible to model signal transmission across entire axonal fibre bundles. We develop a mathematical framework in which we replace the Hodgkin-Huxley dynamics by a spike-diffuse-spike model with passive sub-threshold dynamics and explicit, threshold-activated ion channel currents. This allows us to study in detail the influence of the various model parameters on the action potential velocity and on the entrainment of action potentials between ephaptically coupled fibres without having to recur to numerical simulations. Specifically, we recover known results regarding the influence of axon diameter, node of Ranvier length and internode length on the velocity of action potentials. Additionally, we find that the velocity depends more strongly on the thickness of the myelin sheath than was suggested by previous theoretical studies. We further explain the slowing down and synchronisation of action potentials in ephaptically coupled fibres by their dynamic interaction. In summary, this study presents a solution to incorporate detailed axonal parameters into a whole-brain modelling framework.


Assuntos
Mapeamento Encefálico/métodos , Sincronização Cortical/fisiologia , Fibras Nervosas Mielinizadas/fisiologia , Potenciais de Ação/fisiologia , Algoritmos , Animais , Axônios/fisiologia , Encefalopatias Metabólicas , Simulação por Computador , Humanos , Modelos Neurológicos , Bainha de Mielina/fisiologia , Condução Nervosa/fisiologia , Substância Branca
2.
Muscle Nerve ; 60(6): 687-692, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31478199

RESUMO

INTRODUCTION: Nerve imaging has a limited role in axonal and muscle fiber loss. In this study, we sought to explore the utility of standardized muscle ultrasound (US) assessment in these clinical scenarios. METHODS: We performed a prospective study from March to August 2018 of patients attending the neuromuscular clinic. All patients underwent clinical evaluation and standardized muscle thickness measurement by US in seven muscles. RESULTS: The study cohort consisted of 114 participants, including patients with polyneuropathy, motor neuron disease, and myopathy. The smallest distal muscle thickness was found in patients with polyneuropathy, while the smallest proximal muscle thickness was found in patients with myopathy. Muscle thickness was strongly correlated with muscle strength (r 2 = 0.62), electrophysiological findings (r 2 : 0.44-0.55), and disability score (r 2 = 0.53). DISCUSSION: Standardized muscle thickness measured by US shows diagnostic usefulness in a spectrum of neuromuscular disorders and correlates with clinical and electrophysiological findings.


Assuntos
Músculo Esquelético/diagnóstico por imagem , Doenças Neuromusculares/diagnóstico por imagem , Potenciais de Ação/fisiologia , Adulto , Idoso , Esclerose Amiotrófica Lateral/diagnóstico por imagem , Esclerose Amiotrófica Lateral/patologia , Esclerose Amiotrófica Lateral/fisiopatologia , Eletromiografia , Feminino , Humanos , Masculino , Sintomas Inexplicáveis , Pessoa de Meia-Idade , Força Muscular , Músculo Esquelético/patologia , Músculo Esquelético/fisiopatologia , Atrofia Muscular Espinal/diagnóstico por imagem , Atrofia Muscular Espinal/patologia , Atrofia Muscular Espinal/fisiopatologia , Doenças Musculares/diagnóstico por imagem , Doenças Musculares/patologia , Doenças Musculares/fisiopatologia , Condução Nervosa/fisiologia , Doenças Neuromusculares/patologia , Doenças Neuromusculares/fisiopatologia , Tamanho do Órgão , Polineuropatias/diagnóstico por imagem , Polineuropatias/patologia , Polineuropatias/fisiopatologia , Estudos Prospectivos , Radiculopatia/diagnóstico por imagem , Radiculopatia/patologia , Radiculopatia/fisiopatologia , Ultrassonografia
3.
Top Companion Anim Med ; 36: 1-3, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31472722

RESUMO

This study aimed to evaluate femoral nerve latency time recorded from both vastus lateralis and vastus medialis muscles, in clinically healthy dogs. Eighteen adult dogs were distributed into 2 distinct body mass ranges (Group 1: 1-4.1 kg, n= 9; Group 2: 4.2-13 kg, n= 8), according to the median body mass (4.1 kg). Distal motor latencies for the femoral nerve were obtained in right- and left hind limbs. Platinum surface electrodes were used to record the latency of femoral nerve from the vastus lateralis muscle, whereas coaxial needle electrodes were used to record the latency from the vastus medialis muscle. The distal motor nerve latencies were 1.52 ± .23 milliseconds and 1.69 ± .42 milliseconds, respectively, for vastus lateralis and vastus medialis muscles. There were no significant differences of distal motor nerve latencies between vastus lateralis and vastus medialis muscles. Hind limb length of Group 1 was significant shorter than Group 2. There were no significant differences of latencies between Groups 1 and 2. No significant correlations were observed between latency and body mass, and between latency and hind limb length for dogs of both groups. In conclusion, the femoral motor latency measurement was easy to obtain and may supply additional data in the examination of diseases that affect the hind limbs. Latency values of vastus lateralis longer than 1.52 ± .23 milliseconds in small/medium-sized breeds may be considered as suggestive of a femoral neuropathy.


Assuntos
Cães/fisiologia , Nervo Femoral/fisiologia , Extremidade Inferior/inervação , Músculo Quadríceps/inervação , Animais , Peso Corporal , Feminino , Extremidade Inferior/anatomia & histologia , Masculino , Condução Nervosa/fisiologia
4.
Artigo em Inglês | MEDLINE | ID: mdl-31487774

RESUMO

Pesticide exposure is an important rural public health concern that is linked to a spectrum of health outcomes in farmers. However, little is known about these effects on residents living in close proximity to agricultural fields and who are not involved in regular farming. This paper compared the effects of residential proximity to farming lands on a number of neurological and mental health outcomes in adults. A cross-sectional study was performed on 57 adults involved in farming only occasionally in rural Matlab in Bangladesh. A health and demographic surveillance system (HDSS) and geocoding were used to define proximity to the agricultural field. Neurological health was measured using the trail making test, vibrotactile threshold measurement, and dominant ulnar nerve conduction velocity (NCV) amplitude. An adapted Center for Epidemiological Studies Depression scale (CES-D) questionnaire was used to evaluate mental health. Results indicated that respondents living near agricultural fields had significantly higher vibrotactile threshold in big toes (p < 0.004) and needed a longer time to complete the trail making test (p < 0.004) than those living far from fields after accounting for the covariates. Results of this pilot study suggest further investigations to establish the impact of pesticide exposure among occasional and non-farmers on neurological health outcomes.


Assuntos
Exposição Ambiental/efeitos adversos , Saúde Mental/estatística & dados numéricos , Condução Nervosa/fisiologia , Praguicidas/efeitos adversos , População Rural/estatística & dados numéricos , Teste de Sequência Alfanumérica/estatística & dados numéricos , Adulto , Bangladesh , Estudos Transversais , Fazendas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Condução Nervosa/efeitos dos fármacos , Projetos Piloto , Características de Residência
5.
Muscle Nerve ; 60(6): 673-678, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31465118

RESUMO

INTRODUCTION: Large-fiber neuropathy is rare in neurofibromatosis type 1, but small-fiber neuropathy has not been studied. METHODS: Patients with neurofibromatosis type 1 underwent nerve conduction studies for large-fiber assessment. Small-fiber tests included quantitative thermal thresholds, laser Doppler flare imaging, intraepidermal nerve fiber density, and corneal nerve fiber length. RESULTS: Of the 52 patients enrolled, 31 (60%) were female and the mean age was 33.0 ± 12.3 years. Four (8%) patients had abnormal nerve conduction studies. Small-fiber tests were frequently abnormal: thermal thresholds in 7 (13%); laser Doppler flare imaging in 10 (19%); intraepidermal nerve fiber density in 11 (22%); and corneal nerve fiber length in 27 (52%). The mean corneal nerve fiber length was below normative level (10.1 ± 2.7 mm/mm3 ). DISCUSSION: Small-fiber neuropathy may be common in neurofibromatosis type 1, and should be investigated in symptomatic patients.


Assuntos
Condução Nervosa/fisiologia , Neurofibromatose 1/fisiopatologia , Neuropatia de Pequenas Fibras/fisiopatologia , Adulto , Córnea/inervação , Eletrodiagnóstico , Feminino , Humanos , Microscopia Intravital , Fluxometria por Laser-Doppler , Masculino , Microscopia Confocal , Pessoa de Meia-Idade , Neurofibromatose 1/complicações , Limiar Sensorial , Pele/irrigação sanguínea , Pele/patologia , Neuropatia de Pequenas Fibras/etiologia , Sensação Térmica , Vasodilatação , Adulto Jovem
6.
Muscle Nerve ; 60(6): 744-748, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31469427

RESUMO

INTRODUCTION: Nerve cross-sectional area (CSA) is larger than normal in Charcot-Marie-Tooth disease 1A (CMT1A), although to a variable extent. We explored whether CSA is correlated with CMT clinical severity measured with neuropathy score version 2 (CMTNS2) and its examination subscore (CMTES2) in CMT1A. METHODS: We assessed 56 patients with CMT1A (42 families). They underwent nerve conduction study (NCS) and nerve high-resolution ultrasound (HRUS) of the left median, ulnar, and fibular nerves. RESULTS: Univariate analysis showed NCS and HRUS variables to be significantly correlated with CMTNS2 and CMTES2 and with each other. Multivariate analysis showed that ulnar motor nerve conduction velocity (ß: -0.19) and fibular compound muscle action potential amplitude (-1.50) significantly influenced CMTNS2 and that median forearm CSA significantly influenced CMTNS2 (ß: 5.29) and CMTES2 (4.28). DISCUSSION: Nerve size is significantly associated with clinical scores in CMT1A, which suggests that it might represent a potential biomarker of CMT damage and progression.


Assuntos
Doença de Charcot-Marie-Tooth/fisiopatologia , Nervo Mediano/fisiopatologia , Condução Nervosa/fisiologia , Nervo Fibular/fisiopatologia , Nervo Ulnar/fisiopatologia , Adulto , Doença de Charcot-Marie-Tooth/diagnóstico por imagem , Doença de Charcot-Marie-Tooth/patologia , Feminino , Humanos , Masculino , Nervo Mediano/diagnóstico por imagem , Nervo Mediano/patologia , Pessoa de Meia-Idade , Tamanho do Órgão , Nervo Fibular/diagnóstico por imagem , Nervo Fibular/patologia , Índice de Gravidade de Doença , Nervo Ulnar/diagnóstico por imagem , Nervo Ulnar/patologia , Ultrassonografia
7.
Muscle Nerve ; 60(4): 415-419, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31294858

RESUMO

INTRODUCTION: We present a case series of six treatment-naive patients with clinical phenotypes compatible with chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy without electrodiagnostic features of demyelination but with abnormal peripheral ultrasound findings who responded to treatment. METHODS: All six patients underwent a complete set of ancillary investigations, including extensive nerve conduction studies. We also performed standardized nerve ultrasound of median nerves and brachial plexus as part of a larger effort to evaluate diagnostic value of sonography. RESULTS: Nerve conduction studies did not show conduction block or other signs of demyelination in any of the six patients. Sonographic nerve enlargement was present in all patients and was most prominent in proximal segments of the median nerve and brachial plexus. Treatment with intravenous immunoglobulin resulted in objective clinical improvement. DISCUSSION: Our study provides evidence that nerve ultrasound represents a useful complementary diagnostic tool for the identification of treatment-responsive inflammatory neuropathies.


Assuntos
Plexo Braquial/diagnóstico por imagem , Nervo Mediano/diagnóstico por imagem , Condução Nervosa/fisiologia , Polirradiculoneuropatia Desmielinizante Inflamatória Crônica/diagnóstico por imagem , Idoso , Plexo Braquial/patologia , Plexo Braquial/fisiopatologia , Eletrodiagnóstico , Feminino , Humanos , Imunoglobulinas Intravenosas/uso terapêutico , Fatores Imunológicos/uso terapêutico , Masculino , Nervo Mediano/patologia , Nervo Mediano/fisiopatologia , Pessoa de Meia-Idade , Tamanho do Órgão , Polirradiculoneuropatia Desmielinizante Inflamatória Crônica/fisiopatologia , Polirradiculoneuropatia Desmielinizante Inflamatória Crônica/terapia , Ultrassonografia
8.
J Clin Neurosci ; 67: 10-13, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31272830

RESUMO

Motor conduction blocks (CBs) and decreased motor nerve conduction velocity (MCV) are both demyelination electrophysiological characteristics. Though CBs are both common in Lewis-Sumner syndrome (LSS) and multifocal motor neuropathy (MMN), they are two distinct disease groups, so their MCV and CBs electrophysiological characteristics may be different. In this paper, we aimed to discuss the relationship between CBs and MCV in Lewis-Sumner syndrome (LSS) and multifocal motor neuropathy (MMN). Sixteen patients with LSS and 11 with MMN were retrospectively collected. Motor nerve conduction studies were performed on bilateral median and ulnar nerves. 16/23 segments with CBs in MMN, and 50/53 segments with CBs in LSS had decreased conduction velocities respectively. There was significant difference in MCV between these two groups (MMN 53.1 ±â€¯12.5 m/s; LSS 34.3 ±â€¯17.1 m/s, mean ±â€¯SD, P < 0.05) as well as significant difference in MCV for segment with or without CBs between MMN and LSS patients (P < 0.05). Patients with LSS were prone to be found MCV decrease in segments of motor CB than patients with MMN (P = 0.017). Forty one segments in LSS patients and 6 segments in MMN had MCV ≤ 38 m/s (P < 0.05). There exist two relationships between CB and MCV no matter in LSS or MMN. The characteristics of MCV and CB can be used to distinguish these two disease groups.


Assuntos
Condução Nervosa/fisiologia , Polineuropatias/fisiopatologia , Adulto , Fenômenos Eletrofisiológicos/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Síndrome
9.
Intern Med ; 58(21): 3157-3161, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31292398

RESUMO

Peripheral nerve imaging techniques have recently increasingly revealed their usefulness. We herein describe a man who had a subacute progression of symptom, diffuse and prominent proximal demyelination and conduction block, suggesting a diagnosis of inflammatory demyelinating polyneuropathy. Additional nerve imaging techniques revealed homogeneous and prominent nerve hypertrophy without proximal accentuation and the findings implied inherited polyneuropathies. Intravenous immunoglobulin was administered, and both the symptoms of weakness and findings of nerve conduction studies (NCS) improved. Subsequent genetic testing unveiled Charcot-Marie-Tooth 1A. To diagnose peripheral nerve disorders, a careful history, physical examination and NCS are essential diagnostic tools, but the findings of this case suggest the importance of nerve imaging techniques in clinical situations.


Assuntos
Doença de Charcot-Marie-Tooth/diagnóstico por imagem , Nervos Periféricos/diagnóstico por imagem , Adulto , Doença de Charcot-Marie-Tooth/fisiopatologia , Progressão da Doença , Humanos , Imunoglobulinas Intravenosas/uso terapêutico , Fatores Imunológicos/uso terapêutico , Imagem por Ressonância Magnética , Masculino , Condução Nervosa/fisiologia , Nervos Periféricos/fisiopatologia , Ultrassonografia
10.
Muscle Nerve ; 60(3): 263-270, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31269243

RESUMO

INTRODUCTION: We assessed the specific sonographic pattern of structural nerve abnormalities in immunoglobulin M (IgM) neuropathy and disease controls. METHODS: We enrolled 106 incident patients-32 patients with IgM neuropathy, 42 treatment-naive patients with chronic inflammatory demyelinating polyneuropathy, and 32 patients with axonal neuropathies. All patients underwent standardized ancillary testing in addition to standardized sonography of the brachial plexus and the large arm and leg nerves bilaterally. RESULTS: We found widespread nerve enlargement in IgM neuropathy and chronic inflammatory demyelinating polyneuropathy (CIDP), with specific enlargement of brachial plexus and proximal segments of median nerve but not in axonal disease controls (P < .001). Sonographic nerve hypertrophy in IgM neuropathy was not associated with nerve conduction, clinical, or laboratory characteristics. DISCUSSION: Immunoglobulin M neuropathy is characterized by widespread nerve enlargement indistinguishable from CIDP. Our data provide evidence to confirm that the disease process is not confined to the more distal parts of nerves in either classical demyelinating or axonal variants of neuropathy with associated IgM.


Assuntos
Imunoglobulina M/metabolismo , Glicoproteína Associada a Mielina/metabolismo , Condução Nervosa/fisiologia , Polirradiculoneuropatia Desmielinizante Inflamatória Crônica/fisiopatologia , Idoso , Axônios/fisiologia , Plexo Braquial/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Exame Neurológico/métodos , Polirradiculoneuropatia Desmielinizante Inflamatória Crônica/complicações
11.
Muscle Nerve ; 60(4): 424-428, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31325167

RESUMO

INTRODUCTION: An absent Hoffman (H)-reflex, the electrophysiological equivalent of the Achilles reflex, is assumed to be one of the first detectable signs of polyneuropathy (PNP). In this study we compare the H- and Achilles reflexes in patients with suspected PNP to evaluate the diagnostic utility of the H-reflex. METHODS: Data from clinical examination and nerve conduction studies (NCS) were analyzed in patients with suspected PNP. RESULTS: The PNP diagnosis was confirmed by follow-up in 209 patients. The sensitivities of the H- and Achilles reflexes were similar (70.3% vs 71.8%), whereas the H-reflex had higher specificity (85.2% vs 70.5%) (P < .001). Adding H-reflex to the NCS protocol increased the diagnostic sensitivity from 80.9% to 87.6%. DISCUSSION: The H-reflex is a sensitive method that could provide added value to standard NCS in PNP diagnosis. The simplicity and high specificity make it superior to its clinical equivalent, the Achilles reflex.


Assuntos
Reflexo H/fisiologia , Condução Nervosa/fisiologia , Polineuropatias/diagnóstico , Reflexo Anormal/fisiologia , Tendão do Calcâneo/fisiopatologia , Adulto , Idoso , Eletrodiagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Polineuropatias/fisiopatologia , Reflexo de Estiramento/fisiologia , Sensibilidade e Especificidade
13.
Handb Clin Neurol ; 160: 217-224, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31277849

RESUMO

Nerve conduction studies (NCSs) are an essential tool in the evaluation of the peripheral nervous system. The sensory nerve action potential (SNAP) provides information on the sensory nerve axon and its pathway from the distal receptors in the skin to the dorsal root ganglia, while the compound muscle action potential (CMAP) is an assessment of the motor nerve fibers from their origins in the anterior horn cell to their termination along muscle fibers. Various parameters of the SNAP and CMAP waveforms are used to determine the number of functioning nerve fibers and the speed of conduction. Similarly, specific electrodiagnostic patterns involving SNAP and CMAP amplitudes, latencies and other measurements can help discern the underlying nerve pathophysiology as either axon loss or demyelinating in nature. Numerous technical and environmental factors can affect the NCS and should be recognized and corrected if possible. Finally, while basic NCSs are a noninvasive and low-risk procedure, safety issues for patients with implanted electrical devices should be considered.


Assuntos
Eletromiografia/métodos , Neurônios Motores/fisiologia , Condução Nervosa/fisiologia , Células Receptoras Sensoriais/fisiologia , Potenciais de Ação/fisiologia , Axônios/fisiologia , Humanos
14.
Handb Clin Neurol ; 160: 23-37, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31277851

RESUMO

Waveform analysis plays an important role in the assessment of nerve and muscle action potentials. A sequence of potential changes arises as two sufficiently close wave fronts, leading and trailing dipoles, travel in the volume conductor from left to right. This results in a positive-negative-positive triphasic wave as depolarization and repolarization approach, reach, and finally pass beyond the point of the recording electrode. Physiologic temporal dispersion can reduce the area of a short-duration sensory potential by phase cancellation. Pathologic temporal dispersion, which can reduce the size of muscle action potential, may conversely increase the size of a sensory response by countering the physiologic phase cancellation. The near-field potential relates to the propagating signal recorded when the impulse passes under the pickup electrodes, whereas the far-field potential implies either a distant nonpropagating signal or a stationary peak generated by a propagating signal when it crosses a volume conductor junction located far from the recording site. The second type of far-field signal, or junctional potential, helps detect a voltage source generated at a distance before the signal reaches the pickup electrodes. A consensus has emerged that the volume entered becomes initially positive compared with the volume departed when the generator approaches the boundary of a volume conductor followed by a negative rebound.


Assuntos
Potenciais de Ação/fisiologia , Músculo Esquelético/fisiologia , Condução Nervosa/fisiologia , Animais , Humanos , Estimulação Elétrica Nervosa Transcutânea/métodos
15.
Handb Clin Neurol ; 160: 243-256, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31277852

RESUMO

Needle electromyography (EMG) is the technique of recording and analyzing the electrical signals derived from individual muscle fibers of motor units, at rest and during voluntary contraction, using a needle recording electrode inserted into the muscle. Needle EMG entails inserting a needle electrode into a muscle, recording and amplifying the electrical signals generated from resting or contracting muscle fibers, and interpreting the signals to determine the function of the muscle fibers and motor units. Many factors affect the recorded signals during needle EMG, including the types of needle electrodes and filters and amplifier settings. Different semiquantitative and quantitative methods of analysis of the recorded signals are available, each with advantages and disadvantages. While needle EMG is a safe technique, potential risks include pain, bleeding, and pneumothorax.


Assuntos
Eletromiografia/instrumentação , Eletromiografia/métodos , Neurônios Motores/fisiologia , Agulhas , Condução Nervosa/fisiologia , Potenciais de Ação/fisiologia , Eletrodos/normas , Eletromiografia/normas , Humanos , Agulhas/normas
16.
Handb Clin Neurol ; 160: 3-22, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31277855

RESUMO

The action potential is a regenerative electrical phenomenon observed on excitable cell membranes that allows the propagation of signals without attenuation. It is the cornerstone of neurophysiology. This chapter is a review of the action potential and its relationship to the signals that are studied in clinical neurophysiology. The first section traces the history of key scientific discoveries over the last 250 years that have led to our present-day understanding of the electrical properties of nerve and muscle. The second section considers the molecular and biophysical mechanisms that are responsible for the electrical potentials that can be measured across all eukaryotic cell membranes, but specifically in neurons, nerves, and muscle. Mechanisms underlying propagation action potentials within the nervous system are also examined. The concluding section is a brief overview of the normal "macroscopic" signals that are commonly recorded from the central and peripheral nervous system, and how they are derived from action potentials.


Assuntos
Potenciais de Ação/fisiologia , Neurônios Motores/fisiologia , Condução Nervosa/fisiologia , Junção Neuromuscular/metabolismo , Animais , Eletromiografia/métodos , Humanos , Proteínas de Membrana Transportadoras/metabolismo , Recrutamento Neurofisiológico/fisiologia
17.
Handb Clin Neurol ; 160: 67-81, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31277877

RESUMO

Since the purpose of clinical neurophysiology testing is to record the electrical activity of the nervous system, and often to electrically stimulate the peripheral or central nervous system (for evoked potentials, nerve conduction studies, etc.), these tests by their very nature demand an excellent electrical connection to the patient. This direct electrical connection by definition puts the patient at increased risk of electrical shock. When patients suffer from other nonneurological disorders that also require equipment to be attached to or inserted into their body, the additional and more direct electrical pathways to the heart make them even more vulnerable, especially when undergoing monitoring in the operating room or intensive care unit. Although we depend on the hospital's construction and utilities to follow appropriate regulations (the National Electrical Code in the United States) and on the vendors to sell only safe equipment (approved by the Food and Drug Administration in the United States), there may exist combinations of equipment and connections that put the patient at risk of injurious or fatal electrical shock. Regular testing and safe practices, informed by a scientific understanding of the risks, are the responsibilities of the healthcare providers in order to protect the patient from harm from electricity.


Assuntos
Traumatismos por Eletricidade/prevenção & controle , Terapia por Estimulação Elétrica/efeitos adversos , Monitorização Fisiológica/efeitos adversos , Segurança do Paciente , Traumatismos por Eletricidade/etiologia , Terapia por Estimulação Elétrica/normas , Eletricidade/efeitos adversos , Eletrodos Implantados/efeitos adversos , Humanos , Monitorização Fisiológica/normas , Condução Nervosa/fisiologia , Segurança do Paciente/normas
18.
J Clin Neurosci ; 67: 40-45, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31227403

RESUMO

A common entrapment site of the lateral femoral cutaneous nerve (LFCN) is in the vicinity of the inguinal ligament. However the more distal segment of this nerve can also be affected. Electrophysiological evaluation of this nerve is difficult. Additionally, available methods have failed in the lesion localization of LFCN. In this study, we aimed to evaluate nerve conduction study in different segments of the LFCN. Nerve action potentials of the LFCN were recorded with distal surface electrodes from a relatively distant point (about 30 cm caudal to the spina iliaca anterior superior). An electrical stimulus was given both 10 cm distal to the SIAS and at the level of the SIAS. Inguinal segmental and distal sensory nerve conduction studies were performed on the LFCN. Thirty-eight healthy controls and 34 patients with meralgia paresthetica (MP) were analyzed by this method. All patients with MP showed electrophysiological abnormalities. Slowed sensory conduction on the inguinal channel (p:0.0001) and loss of response were the most frequent abnormalities (44.7% and 31.6%). In one patient, the only abnormality was slowed sensory conduction at the distal site. Our findings suggest that this technique can help in diagnosis and lesion localization in MP.


Assuntos
Eletromiografia/métodos , Nervo Femoral/fisiologia , Neuropatia Femoral/diagnóstico , Síndromes de Compressão Nervosa/diagnóstico , Condução Nervosa/fisiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
19.
Muscle Nerve ; 60(3): 271-278, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31228263

RESUMO

INTRODUCTION: Use of peripheral nerve ultrasound alongside standard electrodiagnostic tests may help to gain insight into the pathophysiology of peripheral nerve involvement in type 2 spinocerebellar ataxia (SCA2). METHODS: Twenty-seven patients with SCA2 underwent ultrasound cross-sectional area (CSA) measurement of median, ulnar, sural and tibial nerves, and motor (median, ulnar, tibial) and sensory (median, ulnar, radial, sural) nerve conduction studies. RESULTS: Twenty patients had pathologically small-nerve CSAs, suggestive of sensory neuronopathy. In these patients, electrophysiology showed non-length-dependent sensory neuropathy (14 of 20), "possible sensory neuropathy" (1 of 20), or normal findings (5 of 20). Four different patients had length-dependent sensory neuropathy on electrophysiology, and 1 had enlarged nerve CSAs. Regression analysis showed an inverse relationship between ataxia scores and upper limb nerve CSA (P < 0.03). DISCUSSION: Our findings suggest that a majority of patients with SCA2 (74%) have a sensory neuronopathy and this correlates with disability. A minority of patients have findings consistent with axonal neuropathy (18%). Muscle Nerve, 2019.


Assuntos
Nervos Periféricos/fisiopatologia , Doenças do Sistema Nervoso Periférico/fisiopatologia , Ataxias Espinocerebelares/fisiopatologia , Extremidade Superior/fisiopatologia , Adulto , Idoso , Ataxia Cerebelar/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas do Tecido Nervoso/metabolismo , Condução Nervosa/fisiologia , Doenças do Sistema Nervoso Periférico/diagnóstico , Transtornos das Sensações/fisiopatologia , Ultrassonografia/métodos
20.
Muscle Nerve ; 60(3): 305-307, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31228276

RESUMO

INTRODUCTION: Nerve 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. METHODS: We 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. RESULTS: We 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). DISCUSSION: Bilateral lower extremity NCS may have limited utility in the evaluation of suspected DSP. Muscle Nerve, 2019.


Assuntos
Neuropatias Diabéticas/fisiopatologia , Condução Nervosa/fisiologia , Polineuropatias/fisiopatologia , Nervo Sural/fisiopatologia , Potenciais de Ação/fisiologia , Adulto , Idoso , Neuropatias Diabéticas/diagnóstico , Eletrodiagnóstico/métodos , Eletromiografia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Polineuropatias/diagnóstico , Estudos Retrospectivos , Nervo Tibial/fisiopatologia
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