Measurements muscle fiber conduction. Medical search. Frequent questions

The purpose of this study was to compare average muscle fiber conduction velocity (CV) and its changes over time in the upper trapezius muscle during a repetitive upper limb task in people with chronic neck pain and in healthy controls. (birmingham.ac.uk)
The time an impulse takes to traverse a measured length of nerve determines conduction velocity. (merckmanuals.com)
Thus, conduction velocity is slowed more when larger myelinated fibers are damaged. (merckmanuals.com)
When unmyelinated axons are damaged, the amplitude of the action potential is decreased, but conduction velocity is relatively unimpaired. (merckmanuals.com)
When a specific neuropathy primarily affects large myelinated fibers, the predominant effect is a decrease in conduction velocity. (merckmanuals.com)
Reliability of surface electromyography in estimating muscle fiber conduction velocity: a systematic review. (supsi.ch)
Test-retest reliability of muscle fiber conduction velocity and fractal dimension of surface EMG during isometric contractions. (supsi.ch)
Which assists to increase the conduction velocity of nerve impulses? (fsu.edu)
However, there is no unanimous agreement, less especially about the nomenclature of the recessive and intermediate-conduction velocity subtypes. (medscape.com)
PNS effects were evaluated in the ulnar and peroneal nerves using measurements of maximum motor nerve conduction velocity and distal latency. (cdc.gov)
The sensory conduction velocity was measured in the sural nerve. (cdc.gov)
Nerve conduction velocity (NCV) is a common measurement made during this test. (wikidoc.org)
The term NCV often is used to mean the actual test, but this is improper use of the term since velocity is only one measurement out of the entire test. (wikidoc.org)
The F-wave study evaluates conduction velocity of nerves between the limb and spine, whereas the motor and sensory nerve conduction studies evaluate conduction in the limb itself. (wikidoc.org)
Slowed nerve conduction velocity and conduction block can be observed at sites susceptible for compression while other regions are unaffected 10 , 11 . (biorxiv.org)
The presence of myelin also increases conduction velocity. (aneskey.com)

In nerve conduction studies, a peripheral nerve is stimulated with electrical shocks at several points along its course to a muscle, and the time to initiation of contraction is recorded. (merckmanuals.com)
Now a large and ever increasing number of genetic subtypes has been described, and major advances in molecular and cellular biology have clarified the understanding of the role of different proteins in the physiology of peripheral nerve conduction in health and in disease. (medscape.com)
Motor NCS are performed by electrical stimulation of a peripheral nerve and recording from a muscle supplied by this nerve. (wikidoc.org)
Indeed, treatment of DRG co-cultures from HNPP mice with PI3K/Akt/mTOR pathway inhibitors reduced focal hypermyelination and, importantly, treatment of HNPP mice with the mTOR inhibitor Rapamycin improved motor behavior, increased compound muscle amplitudes (CMAP) and reduced tomacula formation in the peripheral nerve. (biorxiv.org)
Proper expression of the peripheral myelin protein of 22 kDa (PMP22), an integral constituent of the compact myelin sheath, is important for development and function of peripheral nerve fibers. (biorxiv.org)

In electromyography, a needle is inserted into a muscle, and electrical activity is recorded while the muscle is at rest and when contracting. (merckmanuals.com)
Objective: The aim of this study is to develop a novel method to assess activity-dependent hyperpolarization in human single motor axons at a constant stimulus frequency by using intra-muscular axonal stimulating single fiber electromyography (s-SFEMG). (elsevierpure.com)
Electromyography (EMG) and nerve conduction studies show axonal degeneration and asymmetric involvement. (medscape.com)
We evaluated the relationship between electromyography (EMG) measurements of the pectoralis major (PM) muscle and mastalgia in patients with non-cyclic unilateral mastalgia. (hasekidergisi.com)
Electromyography (EMG) is one of the commonly used diagnostic methods for muscle and nervous system-related disorders such as fibromyalgia (24). (hasekidergisi.com)
Electromyography (EMG) plays a key role in the evaluation of most peripheral neuropathies and helps in assessing only large myelinated fibers. (medscape.com)

As contraction increases, the number of muscle action potentials increases, forming an interference pattern. (merckmanuals.com)
Surviving axons branch to innervate adjacent muscle fibers, enlarging the motor unit and producing giant muscle action potentials. (merckmanuals.com)
In neuropathy, conduction is often slowed, and the response pattern may show a dispersion of action potentials due to unequal involvement of myelinated and unmyelinated nerve fibers. (merckmanuals.com)
However, when neuropathies affect only small umyelinated or thinly myelinated fibers (or when weakness is due to a muscle disorder), the amplitude of action potentials is decreased and nerve conduction velocities are typically normal. (merckmanuals.com)
It was originally developed by Robert Stämpfli for recording action potentials in nerve fibers, and is particularly useful for measuring irreversible or highly variable pharmacological modifications of channel properties since untreated regions of membrane can be pulled into the node between the sucrose regions. (wikipedia.org)
The method was used to study action potentials in nerve fibers. (wikipedia.org)
Methods: We performed s-SFEMG in the extensor digitorum communis (EDC) muscle of 10 normal subjects, and measured changes in latencies for single muscle fiber action potentials (MAPs) during 500 stimuli delivered at 5, 10 and 20. (elsevierpure.com)
There was a significant reduction in the ratio of amplitudes of muscle action potentials measured during peroneal nerve stimulation. (cdc.gov)
F-wave study uses stimulation of a motor nerve and recording of action potentials from a muscle supplied by the nerve. (wikidoc.org)

In the late 1960s, neurophysiologic testing allowed the classification of CMT into 2 groups, one with slow nerve conduction velocities and histologic features of a hypertrophic demyelinating neuropathy (hereditary motor and sensory neuropathy type 1 or CMT1) and another with relatively normal velocities and axonal and neuronal degeneration (hereditary motor and sensory neuropathy type 2 or CMT2). (medscape.com)

Energy deprivation within the axon may be especially critical at nodes of Ranvier, since these nodes demand more energy for impulse conduction and axonal transport. (medscape.com)
Traditionally, CMT pathophysiology has been categorized into 2 processes: a predominant demyelinating process resulting in low conduction velocities (CMT1) and a predominant axonal process resulting in low potential amplitudes (CMT2). (medscape.com)
Thenar muscle atrophy indicates axonal nerve injury in more advanced CTS. (medscape.com)

The interpretation of nerve conduction studies is complex, but in general, different pathological processes result in changes in latencies, motor and/or sensory amplitudes, or slowing of the conduction velocities to differing degrees. (wikidoc.org)

Hypokalemic periodic paralysis (HypoPP) is an ion channelopathy of skeletal muscle characterized by attacks of muscle weakness associated with low serum K + . HypoPP results from a transient failure of muscle fiber excitability. (jci.org)
Initiated by neural impulses and subsequent calcium release, skeletal muscle fibers contract (actively generate force) as a result of repetitive power strokes of acto-myosin cross-bridges. (frontiersin.org)
Recall that cardiac muscle shares a few characteristics with both skeletal muscle and smooth muscle, but it has some unique properties of its own. (lumenlearning.com)
Neither smooth nor skeletal muscle can do this. (lumenlearning.com)
Compared to the giant cylinders of skeletal muscle, cardiac muscle cells, or cardiomyocytes, are considerably shorter with much smaller diameters. (lumenlearning.com)
These contractile elements are virtually identical to skeletal muscle. (lumenlearning.com)
The T tubules are only found at the Z discs, whereas in skeletal muscle, they are found at the junction of the A and I bands. (lumenlearning.com)
Therefore, there are one-half as many T tubules in cardiac muscle as in skeletal muscle. (lumenlearning.com)

Small fibers are both myelinated and unmyelinated. (medscape.com)

Ib afferent fibers causes excitation of antagonist muscles. (symptoma.com)
E. Ia afferent fibers causes excitation of muscles on the contralateral side. (symptoma.com)
The neural elements of somatosensory receptors in the hands and feet represent the distal extreme of long afferent fibers, and thus, are par- ticularly vulnerable in the distal axonopathies. (cdc.gov)

Symptoms include an increase in the muscle tone in the lower extremities, hyperreflexia , positive Babinski and a decrease in fine motor coordination. (symptoma.com)
The typical patient with GBS, which in most cases will manifest as acute inflammatory demyelinating polyradiculoneuropathy (AIDP), presents 2-4 weeks following a relatively benign respiratory or gastrointestinal illness with complaints of finger dysesthesias and proximal muscle weakness of the lower extremities. (medscape.com)

The time required to traverse the segment nearest the muscle is called distal latency. (merckmanuals.com)
Distal latency, residual latency, and muscle or nerve action potential amplitudes did not differ significantly in the study groups. (cdc.gov)

Similar measurements can be made for sensory nerves. (merckmanuals.com)
A nerve conduction study (NCS) is a test commonly used to evaluate the function, especially the ability of electrical conduction , of the motor and sensory nerves of the human body . (wikidoc.org)
This also evaluates conduction between the limb and the spinal cord, but in this case, the afferent impulses (those going towards the spinal cord) are in sensory nerves while the efferent impulses (those coming from the spinal cord) are in motor nerves. (wikidoc.org)

Significance: This technique may detect activity-dependent conduction block if the safety margin of impulse transmission is significantly reduced by demyelination or increased branching due to collateral sprouting in a variety of neuromuscular disorders. (elsevierpure.com)
Nerve conduction studies and biopsy findings are compatible with demyelination. (medscape.com)

After a 7 week treatment period, 12-week-old db/db-vehicle, db/+ -vehicle and db/db-EQ treated animals were evaluated by nerve conduction, paw withdrawal against a hotplate, and fiber density in hindlimb footpads. (nature.com)

Despite the significant latency prolongation, no activity-dependent conduction block developed. (elsevierpure.com)
A mild transient injury may result from interruption of the myelin sheath covering the nerve leading to delayed latency of the recorded compound muscle action potential (CMAP) recorded from the facial muscles. (evokedpotential.com)
Data on age, family history, age of menarche, body mass index (BMI), physical examination, breast ultrasonography and mammography findings and amplitudes, latency and cutaneous silent period (CSP) in EMG of the right and left PM muscles were noted. (hasekidergisi.com)

When determining whether weakness is due to a nerve, muscle, or neuromuscular junction disorder is clinically difficult, these studies can identify the affected nerves and muscles. (merckmanuals.com)
Myasthenia Gravis Myasthenia gravis is characterized by episodic muscle weakness and easy fatigability caused by autoantibody- and cell-mediated destruction of acetylcholine receptors. (merckmanuals.com)
I n the ICU, severe muscle weakness is independently associated with prolonged mechanical ventilation, ICU stay, hospital stay and increased mortality. (health-articles.net)
Physical examination shows diffuse, symmetric weakness involving all extremities and respiratory muscles. (health-articles.net)
Nerve conduction studies are used mainly for evaluation of paresthesias ( numbness , tingling, burning) and/or weakness of the arms and legs. (wikidoc.org)
Postpolio syndrome Most patients with postpolio syndrome (PPS) present with new, slowly progressive muscle weakness, frequently accompanied by muscle pain (myalgias) and fatigue , which can occur in both previously affected and unaffected muscles. (symptoma.com)
Damage to this tract can lead to a number of problems, including paralysis, muscle weakness, loss of muscle control, and tremors . (symptoma.com)
The weakness may progress over hours to days to involve the arms, truncal muscles, cranial nerves, and muscles of respiration. (medscape.com)

It was concluded that membrane muscle fiber properties of the upper trapezius and their changes over time during dynamic contraction of the upper limb are different in a sample of people with chronic neck pain with respect to controls. (birmingham.ac.uk)
CSP is an inhibitory spinal reflex which appears following strong electrical stimulation of a cutaneous nerve and causes suppression of voluntary muscle contraction for a certain period of time. (hasekidergisi.com)
A junction between two adjoining cells is marked by a critical structure called an intercalated disc , which helps support the synchronized contraction of the muscle. (lumenlearning.com)

Most peripheral neuropathies affect all fiber sizes. (medscape.com)
Few peripheral neuropathies are associated with pure or predominantly small fiber involvement. (medscape.com)
Thus, pure small fiber neuropathies may be associated with normal findings on routine electrophysiologic studies. (medscape.com)

HIV induces muscle fibers to express major histocompatibility complex-1 (MHC-1) on their surface, triggering T cell-mediated muscle fiber injury. (medscape.com)
In conclusion, using a whole organ preparation, the authors demonstrated that bupivacaine induces similar impairment in ventricular conduction in newborn and adult rabbits. (silverchair.com)

We discuss implications of our model approach for enhancing muscle models in general, as well as a few aspects regarding the significance of phosphate kinetics as one contributor to muscle fatigue. (frontiersin.org)
One of the first books addressing (muscle as well as whole body) fatigue was published at the beginning of the 20th century ( Mosso, 1904 ) and a multitude of research has followed since, see Gandevia (2001) for a thorough review. (frontiersin.org)
Commonly, muscle fatigue, i.e., the decline of the generable force level over time, is differentiated between central fatigue , i.e., the inability of the neural network to provide sufficient stimulation, and peripheral fatigue , i.e., the inability of the muscle cells to provide energy through metabolic activities (cf. (frontiersin.org)

Techniques focusing on single-fiber conduction may be more sensitive for detecting changes associated with neuromuscular junction disorders such as myasthenia gravis. (merckmanuals.com)
In addition, amplitude modulation of composite EPSPs is similar to single fiber EPSP modulation ( Koerber and Mendell, 1991 ), and therefore an increase in EPSP amplitude resulting from a greater number of afferent connections would not predict a change in high-frequency amplitude modulation. (jneurosci.org)

nerve conduction examination (NCS) was also performed on nine peripheral nerves (common peroneal nerve, tibial nerve, superficial peroneal nerve, sural nerve, plantar nerve, lateral femoral cutaneous nerve, median nerve, radial nerve and ulnar nerve). (biomedcentral.com)
Elderly patients who lack sural sensory responses can still be diagnosed with small fiber neuropathy. (medscape.com)

In 1971, Dyck and colleagues established the current concept of uremic neuropathy based on their extensive nerve conduction studies in vivo and in vitro, as well as light and electron microscopy studies. (medscape.com)
Painful burning feet is caused by a sensory neuropathy with small fiber involvement in more than 90% of cases. (medscape.com)

Surface EMG signals were detected bilaterally from the upper trapezius muscle of 19 patients and nine healthy controls using linear adhesive arrays of four electrodes. (birmingham.ac.uk)
Trapezius myalgia (TM) is the complaint of pain, stiffness, and tightness of the upper trapezius muscle. (physio-pedia.com)

The ECG involves the recording of the electrical activity of all cardiac muscle fibers of the heart. (internist-wilmersdorf.de)
Even though cardiac muscle has autorhythmicity, heart rate is modulated by the endocrine and nervous systems. (lumenlearning.com)
There are two major types of cardiac muscle cells: myocardial contractile cells and myocardial conducting cells. (lumenlearning.com)
Cardiac muscle also demonstrates striations, the alternating pattern of dark A bands and light I bands attributed to the precise arrangement of the myofilaments and fibrils that are organized in sarcomeres along the length of the cell. (lumenlearning.com)
Cardiac muscle cells branch freely. (lumenlearning.com)
a) Cardiac muscle cells have myofibrils composed of myofilaments arranged in sarcomeres, T tubules to transmit the impulse from the sarcolemma to the interior of the cell, numerous mitochondria for energy, and intercalated discs that are found at the junction of different cardiac muscle cells. (lumenlearning.com)
b) A photomicrograph of cardiac muscle cells shows the nuclei and intercalated discs. (lumenlearning.com)
c) An intercalated disc connects cardiac muscle cells and consists of desmosomes and gap junctions. (lumenlearning.com)
Cardiac muscle undergoes aerobic respiration patterns, primarily metabolizing lipids and carbohydrates. (lumenlearning.com)
Cardiac muscle cells undergo twitch-type contractions with long refractory periods followed by brief relaxation periods. (lumenlearning.com)

The afferent arm of the CSP is formed by somatic small-diameter fibers. (hasekidergisi.com)
Small myelinated fibers transmit preganglionic autonomic efferents (B fibers) and somatic afferents (A delta fibers). (medscape.com)
Unmyelinated (C) fibers transmit postganglionic autonomic efferents as well as somatic and autonomic afferents. (medscape.com)

Maximal inspiratory pressures and vital capacities are measurements of neuromuscular respiratory function and predict diaphragmatic strength. (medscape.com)

Glucocorticoids are known to decrease protein synthesis and impair membrane excitability of muscle fibers. (qxmd.com)
Under normal or resting circumstances, the neural membrane is characterized by a negative potential of roughly -90 mV (the potential inside the nerve fiber is negative relative to the extracellular fluid). (aneskey.com)

Fraser and Arieff postulated that neurotoxic compounds deplete energy supplies in the axon by inhibiting nerve fiber enzymes required for maintenance of energy production. (medscape.com)

Atlas of muscle innervation zones for proper SEMG electrode placement: preliminary results. (supsi.ch)
Innervation zone locations in 43 superficial muscles: towards a standardization of electrode positioning. (supsi.ch)

It is useful in the study of small nerve fibers and electrically connected cells such as smooth muscle cell. (wikipedia.org)

Mutations of Na V 1.4 give rise to a heterogeneous group of muscle disorders, with gain-of-function defects causing myotonia or hyperkalemic periodic paralysis. (jci.org)
Some of the common disorders which can be diagnosed by nerve conduction studies. (wikidoc.org)
Women's work tasks involve more static load on the neck muscles, high repetitiveness, low control, and high mental demands, which are all risk factors for developing neck disorders. (physio-pedia.com)

Electromyographic studies and nerve conduction studies primarily measure motor fiber (the nerves that move your muscles) conduction speed. (dmpdiagnostics.com)

Treated patients may develop inflammatory myopathy related to immune restoration or drug-induced muscle involvement. (medscape.com)
Patients with pure small fiber involvement display normal large fiber function. (medscape.com)

Even in cases where only the Facial Nerve is at risk, the extra channels can be hooked to the contralateral facial muscles to provide a valuable control for nonspecific increases in EMG activity due to light anesthesia or other nonsurgical factors. (evokedpotential.com)

Why aren't my EMG/nerve conduction studies abnormal? (dmpdiagnostics.com)

H-reflex study uses stimulation of a nerve and recording the reflex electrical discharge from a muscle in the limb. (wikidoc.org)

In this case, comparing biomechanical measurements of stiffness and failure load of two upper ankle arthrodesis methods had to be carried out: the screw arthrodesis and the arthrodesis using osteosynthesis plates. (degruyter.com)

Here, two databases available on the CapgMyo network and the Ninapro project are studied, their characteristics are evaluated, with the objective of investigating the variability of the muscle signal between subjects, the factors that modify it and how the use of analysis affects principal components (PCA) and independent component analysis (ICA) to EMG information in classification models. (uabc.mx)
Second, axotomy eliminates access to trophic factors supplied by the muscle. (jneurosci.org)

There is hypertonia (increased muscle tone, stiffness), hyperreflexia (exaggerated reflexes), and an oscillatory movement known as clonus. (symptoma.com)

The EMG results of PM muscles in healthy and mastalgia sides were compared and there was no significant difference observed between the amplitude and resistance parameters. (hasekidergisi.com)

Synaptic efficacy at the rat Ia-motoneuron synapse has been reported to increase in vivo , within 3 d of sectioning a single muscle nerve ( Miyata and Yasuda, 1988 ). (jneurosci.org)
Short and long-term changes in synaptic efficacy occur in vivo at the central synapse between muscle spindle afferents (Ia) and spinal motoneurons ( Mendell, 1984 ). (jneurosci.org)

Atlas of muscle innervation zones for proper sEMG electrodes placement: trunk and upper quadrant. (supsi.ch)

Atrophy of the thenar muscle group is a late sign (see Motor examination below). (medscape.com)
The exact measurement process is fully described in the Oral Examination Component manual (U.S. DHHS, 1996b). (cdc.gov)

The test device allows the measurement of the stiffness and the failure load of the arthrodetic ankle joint with dynamical load in varus/valgus and plantar-/dorsiflexion direction. (degruyter.com)

Our objective was to investigate whether steroid administration could decrease the circulating levels of muscle proteins and modify myoelectric indexes of sarcolemmal excitability and fatigability. (qxmd.com)
In contrast, no significant changes were observed in muscle excitability and fatigability in subjects who received the placebo. (qxmd.com)

If you cut a nerve in half, and look at the various types of nerve fibers within a nerve, over 90% of the nerve fibers are motor fibers, and less than 10% are sensory nerve fibers. (dmpdiagnostics.com)

I have pain in my arm or leg but my EMG/nerve conduction studies are normal. (dmpdiagnostics.com)

Because of the loss of muscle bulk through atrophy, rigor mortis is usually absent in advanced stages of ALS disease. (symptoma.com)

The CSP is a prospective electrophysiological method for the diagnosis of small fiber dysfunction. (hasekidergisi.com)

Blood sampling, force measurements for knee extensors and elbow flexors, and electrophysiological tests for biceps brachii, vastus lateralis and medialis, and tibialis anterior muscles were performed before and after the intervention. (qxmd.com)
The demonstration that glucocorticoid-induced muscle impairments can be unraveled by means of blood sampling and noninvasive electrophysiological tests has clinical implications for the early identification of subclinical or preclinical forms of myopathy in treated patients. (qxmd.com)

When the heart muscle is damaged, cardiac output decreases which stimulates the nervous system to compensate. (ceufast.com)

How would taking this 'prescription' affect the excitability of your muscle? (fsu.edu)

Anatomy72

Organisms24

Diseases28

Chemicals and Drugs42

Analytical, Diagnostic and Therapeutic Techniques and Equipment32

Psychiatry and Psychology2

Phenomena and Processes52

Disciplines and Occupations5

Anthropology, Education, Sociology and Social Phenomena2

Technology, Industry, Agriculture2

Information Science5

Health Care5

Velocity16

Peripheral nerve5

Electromyography6

Action potentials9

Nerve conduction velocities1

Axonal3

Velocities1

Skeletal Muscle8

Myelinated and unmyelinated1

Afferent fibers3

Lower extremities2

Distal latency2

Sensory nerves3

Demyelination2

Evaluated by nerve1

Latency3

Weakness8

Contraction3

Neuropathies3

Induces2

Fatigue3

Single-fiber2

Sural2

Neuropathy2

Upper trapezius muscle2

Cardiac muscle10

Somatic3

Neuromuscular1

Membrane2

Axon1

Electrode2

Electrically1

Disorders3

Primarily1

Involvement2

Increases1

Abnormal1

Stimulation1

Biomechanical1

Factors2

Reflexes1

Amplitude1

Vivo2

Innervation zones1

Examination2

Stiffness1

Fatigability2

Motor1

Normal1

Atrophy1

Dysfunction1

Electrophysiological2

Nervous system1

Excitability1