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130-687: EMG may refer to: Medicine and science [ edit ] Electromyography , a technique for evaluating and recording electrical activity produced by skeletal muscles Exponentially modified Gaussian distribution , in probability theory Ɱ , or emg, a symbol used to transcribe a specific sound in the International Phonetic Alphabet Organisations [ edit ] East Mediterranean Gas Company, an Egyptian pipeline company EMG, Inc. , an American guitar pickup manufacturer E.M.G. Hand-Made Gramophones ,

260-450: A British gramophone manufacturer Escape Media Group, Inc., owner of Grooveshark Essential Media Group, former name of EQ Media Group Euclid Media Group , an American media company Executive Music Group , an American record label Other [ edit ] Eastern Mewahang language European Masters Games Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

390-433: A better understanding of the properties of surface EMG recording. Surface electromyography is increasingly used for recording from superficial muscles in clinical or kinesiological protocols, where intramuscular electrodes are used for investigating deep muscles or localized muscle activity. There are many applications for the use of EMG. EMG is used clinically for the diagnosis of neurological and neuromuscular problems. It

520-435: A control signal for prosthetic devices such as prosthetic hands, arms and lower limbs. An acceleromyograph may be used for neuromuscular monitoring in general anesthesia with neuromuscular-blocking drugs , in order to avoid postoperative residual curarization (PORC). Except in the case of some purely primary myopathic conditions EMG is usually performed with another electrodiagnostic medicine test that measures

650-715: A different outcome than regular discectomy. For most other conditions, there is not enough evidence to provide recommendations for surgical options. The long-term effect surgery has on degenerative disc disease is not clear. Less invasive surgical options have improved recovery times, but evidence regarding effectiveness is insufficient. For those with pain localized to the lower back due to disc degeneration, fair evidence supports spinal fusion as equal to intensive physical therapy and slightly better than low-intensity nonsurgical measures. Fusion may be considered for those with low back pain from acquired displaced vertebra that does not improve with conservative treatment, although only

780-463: A few of those who have spinal fusion experience good results, and there may be no clinically important difference between disk replacement and fusion surgery. There are a number of different surgical procedures to achieve fusion, with no clear evidence of one being better than the others. Adding spinal implant devices during fusion increases the risk but provides no added improvement in pain or function. Spinal cord stimulation using implanted electrodes

910-545: A form of treatment, but this is not recommended to treat acute or subacute low back pain. Motor control exercise, which involves guided movement and use of normal muscles during simple tasks which then builds to more complex tasks, improves pain and function up to 20 weeks, but there was little difference compared to manual therapy and other forms of exercise. Motor control exercise accompanied by manual therapy also produces similar reductions in pain intensity when compared to general strength and condition exercise training, yet only

1040-441: A greater risk of side effects, including dizziness, nausea, and constipation. Opioid treatment for chronic low back pain increases the risk for lifetime illicit drug use and the effect of long-term use of opioids for lower back pain is unknown. For older people with chronic pain, opioids may be used in those for whom NSAIDs present too great a risk, including those with diabetes, stomach or heart problems. They may also be useful for

1170-562: A herniated disc that is causing significant pain radiating into the leg, significant leg weakness, bladder problems, or loss of bowel control. It may also be useful in those with spinal stenosis . In the absence of these issues, there is no clear evidence of a benefit from surgery. Discectomy (the partial removal of a disc that is causing leg pain) can provide pain relief sooner than nonsurgical treatments. Discectomy has better outcomes at one year but not at four to ten years. The less invasive microdiscectomy has not been shown to result in

1300-574: A highly specialized muscle of the electric ray fish ( Electric Eel ) generated electricity. By 1773, Walsh had been able to demonstrate that the eel fish's muscle tissue could generate a spark of electricity. In 1792, a publication entitled De Viribus Electricitatis in Motu Musculari Commentarius appeared, written by Luigi Galvani , in which the author demonstrated that electricity could initiate muscle contraction. Six decades later, in 1849, Emil du Bois-Reymond discovered that it

1430-579: A joystick-controlled wheelchair. Surface EMG recordings may also be a suitable control signal for some interactive video games. A joint project involving Microsoft , the University of Washington in Seattle , and the University of Toronto in Canada has explored using muscle signals from hand gestures as an interface device. A patent based on this research was submitted on June 26, 2008. In 2016

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1560-502: A means of analyzing peak force and force generated by target muscles. According to the article "Peak and average rectified EMG measures: Which method of data reduction should be used for assessing core training exercises?", it was concluded that the "average rectified EMG data (ARV) is significantly less variable when measuring the muscle activity of the core musculature compared to the peak EMG variable." Therefore, these researchers would suggest that "ARV EMG data should be recorded alongside

1690-400: A more serious underlying problem and is classified as needing urgent or specialized attention . The symptoms can also be classified by duration as acute, sub-chronic (also known as sub-acute), or chronic. The specific duration required to meet each of these is not universally agreed upon, but generally pain lasting less than six weeks is classified as acute , pain lasting six to twelve weeks

1820-440: A motor unit fires, the impulse (called an action potential ) is carried down the motor neuron to the muscle. The area where the nerve contacts the muscle is called the neuromuscular junction , or the motor end plate . After the action potential is transmitted across the neuromuscular junction, an action potential is elicited in all of the innervated muscle fibers of that particular motor unit. The sum of all this electrical activity

1950-414: A muscle twitch or by surface electrodes. Fibrillations, however, are detected only by needle EMG, and represent the isolated activation of individual muscle fibers, usually as the result of nerve or muscle disease. Often, fibrillations are triggered by needle movement (insertional activity) and persist for several seconds or more after the movement ceases. After assessing resting and insertional activity,

2080-401: A pair of electrodes or by a more complex array of multiple electrodes. More than one electrode is needed because EMG recordings display the potential difference (voltage difference) between two separate electrodes. Limitations of this approach are the fact that surface electrode recordings are restricted to superficial muscles, are influenced by the depth of the subcutaneous tissue at the site of

2210-425: A patient's motivation and attitude toward their recovery. Education about an injury and how it can effect a person's mental health is just as important as the physical rehabilitation. However, all of these interventions should occur in partnership with a structured therapeutic exercise program and assistance from a trained physical therapist. Most people with acute or subacute low back pain improve over time no matter

2340-502: A person to a computer. In this project, an EMG signal is used to substitute for mechanical joysticks and keyboards. EMG has also been used in research towards a "wearable cockpit", which employs EMG-based gestures to manipulate switches and control sticks necessary for flight in conjunction with a goggle-based display. Unvoiced or silent speech recognition recognizes speech by observing the EMG activity of muscles associated with speech. It

2470-627: A person's quality of life were found. There is very weak evidence that acupuncture may be better than no treatment at all for immediate relief. A 2012 systematic review reported the findings that for people with chronic pain, acupuncture may improve pain a little more than no treatment and about the same as medications, but it does not help with disability. This pain benefit is only present right after treatment and not at follow-up. Acupuncture may be an option for those with chronic pain that does not respond to other treatments like conservative care and medications, however this depends on patient preference,

2600-424: A physical treatment. MBR also has a positive influence on work status of the patient compared to physical treatment. Effects are of a modest magnitude and should be balanced against the time and resource requirements of MBR programs. Peripheral nerve stimulation , a minimally-invasive procedure, may be useful in cases of chronic low back pain that do not respond to other measures, although the evidence supporting it

2730-409: A safety hazard. However, there are theoretical concerns that electrical impulses of nerve conduction studies (NCS) could be erroneously sensed by devices and result in unintended inhibition or triggering of output or reprogramming of the device. In general, the closer the stimulation site is to the pacemaker and pacing leads, the greater the chance for inducing a voltage of sufficient amplitude to inhibit

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2860-480: A select group of people with neuropathic pain . Antidepressants may be effective for treating chronic pain associated with symptoms of depression, but they have a risk of side effects. Although the antiseizure drugs gabapentin , pregabalin , and topiramate are sometimes used for chronic low back pain evidence does not support a benefit. Systemic oral steroids have not been shown to be useful in low back pain. Facet joint injections and steroid injections into

2990-562: A self taught electrical engineer, developed a machine that could be moved from the EMG Lab, and was relatively easy to use. As oscilloscopes had no "store" or "print" features at the time, a Polaroid camera was affixed to the front on a hinge. It was synchronized to photo the scan. Fellows studying at Mayo soon learned that this was a tool they wanted, too. As Mayo has no interest in marketing their inventions, Schmidt went on to continue to develop them in his basement for decades, selling them under

3120-410: A shorter duration of sleep, and less satisfaction with sleep. In addition, a majority of those with chronic low back pain show symptoms of depression or anxiety . Low back pain is not a specific disease but rather a complaint that may be caused by a large number of underlying problems of varying levels of seriousness. The majority of low back pain does not have a clear cause but is believed to be

3250-431: A specific cause identified, but are thought to be due to muscle strain or injury to ligaments. Rarely, complaints of low back pain result from systemic or psychological problems, such as fibromyalgia and somatoform disorders . Low back pain may be classified based on the signs and symptoms. Diffuse pain that does not change in response to particular movements, and is localized to the lower back without radiating beyond

3380-500: A specific disc causing pain in those with chronic high levels of low back pain. Therapeutic procedures such as nerve blocks can also be used to determine a specific source of pain. Some evidence supports the use of facet joint injections , transforminal epidural injections and sacroiliac injections as diagnostic tests. Most other physical tests, such as evaluating for scoliosis , muscle weakness or wasting, and impaired reflexes, are of little use. Complaints of low back pain are one of

3510-487: A startup called Emteq Labs launched a virtual reality headset with embedded EMG sensors for measuring facial expressions. In September 2019 Facebook, later renamed Meta Platforms , bought a startup called CTRL-labs that was working on EMG. In 2024, Meta unveiled augmented reality glasses that were paired with a wristband that reads a user's hand gestures using electromyography. Low back pain Low back pain or lumbago

3640-404: A surface reference, in this case, however, the metal shaft of a hypodermic needle, insulated so that only the tip is exposed, is used both to record signals and to inject. Slightly more complex in design is the concentric needle electrode. These needles have a fine wire, embedded in a layer of insulation that fills the barrel of a hypodermic needle, that has an exposed shaft, and the shaft serves as

3770-446: A thorough analysis, the measured EMG signals can be decomposed into their constituent MUAPs. MUAPs from different motor units tend to have different characteristic shapes, while MUAPs recorded by the same electrode from the same motor unit are typically similar. Notably MUAP size and shape depend on where the electrode is located with respect to the fibers and so can appear to be different if the electrode moves position. EMG decomposition

3900-424: A variety of clinical and biomedical applications. Needle EMG is used as a diagnostics tool for identifying neuromuscular diseases , or as a research tool for studying kinesiology , and disorders of motor control. EMG signals are sometimes used to guide botulinum toxin or phenol injections into muscles. Surface EMG is used for functional diagnosis and during instrumental motion analysis. EMG signals are also used as

4030-411: A very local picture of the activity of the whole muscle. Because skeletal muscles differ in the inner structure, the electrode has to be placed at various locations to obtain an accurate study. For the interpretation of EMG study is important to evaluate parameters of tested muscle motor units. This process may well be partially automated using appropriate software. Single fiber electromyography assesses

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4160-796: A whole, are poorly supported by evidence. The herbal treatments Devil's claw and white willow may reduce the number of individuals reporting high levels of pain; however, for those taking pain relievers, this difference is not significant. Capsicum , in the form of either a gel or a plaster cast, has been found to reduce pain and increase function. Behavioral therapy may be useful for chronic pain. There are several types available, including operant conditioning , which uses reinforcement to reduce undesirable behaviors and increase desirable behaviors; cognitive behavioral therapy , which helps people identify and correct negative thinking and behavior; and respondent conditioning , which can modify an individual's physiological response to pain. The benefit however

4290-401: Is sub-chronic , and more than twelve weeks is chronic . Management and prognosis may change based on the duration of symptoms. The presence of certain signs, termed red flags , indicate the need for further testing to look for more serious underlying problems, which may require immediate or specific treatment. The presence of a red flag does not mean that there is a significant problem. It

4420-417: Is a common disorder involving the muscles, nerves, and bones of the back , in between the lower edge of the ribs and the lower fold of the buttocks. Pain can vary from a dull constant ache to a sudden sharp feeling. Low back pain may be classified by duration as acute (pain lasting less than 6 weeks), sub-chronic (6 to 12 weeks), or chronic (more than 12 weeks). The condition may be further classified by

4550-530: Is a monopolar needle electrode. This can be a fine wire inserted into a muscle with a surface electrode as a reference; or two fine wires inserted into muscle referenced to each other. Most commonly fine wire recordings are for research or kinesiology studies. Diagnostic monopolar EMG electrodes are typically insulated and stiff enough to penetrate skin, with only the tip exposed using a surface electrode for reference. Needles for injecting therapeutic botulinum toxin or phenol are typically monopolar electrodes that use

4680-706: Is also probably effective in preventing recurrences in those with pain that has lasted more than six weeks. Assessing chronic low back pain, a 2007 review concluded that a firm mattress is less likely to alleviate pain compared to a medium-firm mattress, while a 2020 review stated that studies have been inadequate to comment on mattress firmness. There is little to no evidence that back belts are any more helpful in preventing low back pain than education about proper lifting techniques. Shoe insoles do not help prevent low back pain. Studies have proven that interventions aimed to reduce pain and functional disability need to be accompanied by psychological interventions to improve

4810-408: Is assessed with surface electrodes, but it should be recognized that these typically record only from muscle fibers in close proximity to the surface. Several analytical methods for determining muscle activation are commonly used depending on the application. The use of mean EMG activation or the peak contraction value is a debated topic. Most studies commonly use the maximal voluntary contraction as

4940-550: Is associated with higher rates of surgery with no overall benefit, and the radiation used may be harmful to one's health. Fewer than 1% of imaging tests identify the cause of the problem. Imaging may also detect harmless abnormalities, encouraging people to request further unnecessary testing or to worry. Even so, MRI scans of the lumbar region increased by more than 300% among United States Medicare beneficiaries from 1994 to 2006. Exercise alone, or along with education, appears to be useful for preventing low back pain. Exercise

5070-400: Is increased, more and more muscle fibers produce action potentials. When the muscle is fully contracted, there should appear a disorderly group of action potentials of varying rates and amplitudes (a complete recruitment); this can be described as an interference pattern . EMG findings vary with the type of disorder, the duration of the problem, the age of the patient, the degree to which

5200-405: Is insufficient evidence to recommend manipulation under anaesthesia , or medically assisted manipulation. SMT does not provide significant benefits compared to motor control exercises. The evidence supporting acupuncture treatment for providing clinically beneficial acute and chronic pain relief is very weak. When compared to a 'sham' treatment, no differences in pain relief or improvements in

5330-406: Is insufficient, medication may be recommended. As pain medications are only somewhat effective, expectations regarding their benefit may differ from reality, and this can lead to decreased satisfaction. The medication typically prescribed first are acetaminophen (paracetamol), NSAIDs (though not aspirin), or skeletal muscle relaxants and these are enough for most people. Benefits with NSAIDs

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5460-409: Is known as a motor unit action potential (MUAP). This electrophysiologic activity from multiple motor units is the signal typically evaluated during an EMG. The composition of the motor unit, the number of muscle fibres per motor unit, the metabolic type of muscle fibres and many other factors affect the shape of the motor unit potentials in the myogram. Nerve conduction testing is also often done at

5590-412: Is less space through which the spinal cord and nerve roots may pass. When a disc degenerates as a result of injury or disease, the makeup of a disc changes: blood vessels and nerves may grow into its interior and/or herniated disc material can push directly on a nerve root. Any of these changes may result in back pain. Pain erupts in response to a stimulus that either damages or can potentially damage

5720-458: Is monitored using surface EMG and patients have an auditory or visual stimulus to help them know when they are activating the muscle (biofeedback). A review of the literature on surface EMG published in 2008, concluded that surface EMG may be useful to detect the presence of neuromuscular disease (level C rating, class III data), but there are insufficient data to support its utility for distinguishing between neuropathic and myopathic conditions or for

5850-439: Is no evidence that one particular type of exercise therapy is more effective than another, so the form of exercise used can be based on patient or practitioner preference, availability and cost. The Alexander technique appears useful for chronic back pain, and there is some evidence to support small benefits from the use of yoga . If a person with chronic low back pain is motivated, it is recommended to use yoga and tai chi as

5980-402: Is no evidence to support the use of COX-2 inhibitors over any other class of NSAIDs with respect to benefits. With respect to safety naproxen may be best. Muscle relaxants may be beneficial. Systemic corticosteriods are sometimes suggested for low back pain and may have a small benefit in the short-term for radicular low back pain, however, the benefit for non-radicular back pain and

6110-433: Is non-trivial, although many methods have been proposed. Rectification is the translation of the raw EMG signal to a signal with a single polarity , usually positive. The purpose of rectifying the signal is to ensure the signal does not average to zero, due to the raw EMG signal having positive and negative components. Two types of rectification are used: full-wave and half-wave rectification. Full-wave rectification adds

6240-444: Is not conclusive, and it is not effective for pain that radiates into the leg. Evidence for the use of shoe insoles as a treatment is inconclusive. Transcutaneous electrical nerve stimulation (TENS) has not been found to be effective in chronic low back pain. There has been little research that supports the use of lumbar extension machines and thus they are not recommended. If initial management with non–medication based treatments

6370-422: Is not enough evidence to recommend them confidently. The evidence for chiropractic care and spinal manipulation is mixed. Approximately 9–12% of people (632 million) have low back pain at any given point in time, and nearly 25% report having it at some point over any one-month period. About 40% of people have low back pain at some point in their lives, with estimates as high as 80% among people in

6500-543: Is not recommended for people that have no preexisting condition that limits their progressive walking. There is low-to-moderate quality evidence that supports pilates in low back pain for the reduction of pain and disability, however there is no conclusive evidence that pilates is better than any other form of exercise for low back pain. Patients with chronic low back pain receiving multidisciplinary biopsychosocial rehabilitation (MBR) programs are likely to experience less pain and disability than those receiving usual care or

6630-532: Is not supported by evidence due to the potential risks and costs. It is unclear if alternative treatments are useful for non-chronic back pain. Chiropractic care or spinal manipulation therapy (SMT) appear similarly effective to other recommended treatments. National guidelines differ, with some not recommending SMT, some describing manipulation as optional, and others recommending a short course for those who do not improve with other treatments. A 2017 review recommended SMT based on low-quality evidence. There

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6760-431: Is nothing to suggest that they help with the pain. Ultrasound and shock wave therapies do not appear effective and therefore are not recommended. Lumbar traction lacks effectiveness as an intervention for radicular low back pain. It is also unclear whether lumbar supports are an effective treatment intervention. Exercise therapy is effective in decreasing pain and improving physical function, trunk muscle strength and

6890-503: Is only suggestive, and most people with red flags have no serious underlying problem. If no red flags are present, performing diagnostic imaging or laboratory testing in the first four weeks after the start of the symptoms has not been shown to be useful. The usefulness of many red flags is poorly supported by evidence. The most useful for detecting a fracture are: older age, corticosteroid use, and significant trauma especially if it results in skin markings. The best determinant of

7020-591: Is produced. This enables definition of a class of subtle motionless gestures to control interfaces without being noticed and without disrupting the surrounding environment. These signals can be used to control a prosthesis or as a control signal for an electronic device such as a mobile phone or PDA . EMG signals have been targeted as control for flight systems. The Human Senses Group at the NASA Ames Research Center at Moffett Field , CA seeks to advance man-machine interfaces by directly connecting

7150-412: Is recommended for suspected cancer, infection, or cauda equina syndrome . MRI is slightly better than CT for identifying disc disease; the two technologies are equally useful for diagnosing spinal stenosis. Only a few physical diagnostic tests are helpful. The straight leg raise test is almost always positive in those with disc herniation, and lumbar provocative discography may be useful to identify

7280-441: Is recommended only if low back pain is considered a symptom. Mechanical massage tools are not recommended for the treatment of any form of low back pain. Prolotherapy – the practice of injecting solutions into joints (or other areas) to cause inflammation and thereby stimulate the body's healing response – has not been found to be effective by itself, although it may be helpful when added to another therapy. Herbal medicines, as

7410-402: Is somewhat effective for recurrent acute low back pain, but its benefit in the short term does not appear significant. There is tentative evidence to support the use of heat therapy for acute and sub-chronic low back pain but little evidence for the use of either heat or cold therapy in chronic pain. Weak evidence suggests that back belts might decrease the number of missed workdays, but there

7540-694: Is strongly recommended for chronic low back pain, and is recommended after surgery. Directional exercises, which try to limit low back pain, are recommended in sub-acute, chronic and radicular low back pain. These exercises only work if they are limiting low back pain. Exercise programs that incorporate stretching only are not recommended for acute low back pain. Stretching, especially with limited range of motion , can impede future progression of treatment like limiting strength and limiting exercises. Yoga and Tai chi are not recommended in case of acute or subacute low back pain, but are recommended in case of chronic back pain. Treatment according to McKenzie method

7670-412: Is targeted for use in noisy environments, and may be helpful for people without vocal cords , with aphasia , with dysphonia , and more. EMG has also been used as a control signal for computers and other devices. An interface device based on an EMG Switch can be used to control moving objects, such as mobile robots or an electric wheelchair . This may be helpful for individuals that cannot operate

7800-401: Is the cause: mechanical problems, non-mechanical problems, or referred pain. For acute pain that is causing only mild to moderate problems, the goals are to restore normal function, return the individual to work, and minimize pain. The condition is normally not serious, resolves without much being done, and recovery is helped by attempting to return to normal activities as soon as possible within

7930-441: Is thought to be small, but is more effective than Acetaminophen (paracetamol), which may be no more effective than placebo at improving pain, quality of life, or function. NSAIDs however, carry a greater risk of side effects, including kidney failure , stomach ulcers and possibly heart problems , so it is used at the lowest effective dosage for the shortest possible time. NSAIDs are available in several different classes; there

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8060-399: Is used diagnostically by gait laboratories and by clinicians trained in the use of biofeedback or ergonomic assessment. EMG is also used in many types of research laboratories, including those involved in biomechanics , motor control, neuromuscular physiology, movement disorders, postural control, and physical therapy . EMG can be used to sense isometric muscular activity where no movement

8190-409: The amplitude and duration of the muscle action potential and an overall shift to lower frequencies. Monitoring the changes of different frequency changes the most common way of using EMG to determine levels of fatigue. The lower conduction velocities enable the slower motor neurons to remain active. A motor unit is defined as one motor neuron and all of the muscle fibers it innervates. When

8320-462: The buttocks , is classified as nonspecific , the most common classification. Pain that radiates down the leg below the knee, is located on one side (in the case of disc herniation), or is on both sides (in spinal stenosis), and changes in severity in response to certain positions or maneuvers is radicular , making up 7% of cases. Pain that is accompanied by red flags such as trauma, fever, a history of cancer or significant muscle weakness may indicate

8450-411: The developed world . Low back pain is the greatest contributor to lost productivity, absenteeism, disability and early retirement worldwide. Difficulty with low back pain most often begins between 20 and 40 years of age. Women and older people have higher estimated rates of lower back pain and also higher disability estimates. Low back pain is more common among people aged between 40 and 80 years, with

8580-415: The 1930s through the 1950s, and researchers began to use improved electrodes more widely for the study of muscles. The AANEM was formed in 1953 as one of several currently active medical societies with a special interest in advancing the science and clinical use of the technique. Clinical use of surface EMG (sEMG) for the treatment of more specific disorders began in the 1960s. Hardyck and his researchers were

8710-420: The EMG signal below the baseline to the signal above the baseline to make a conditioned signal that is all positive. If the baseline is zero, this is equivalent to taking the absolute value of the signal. This is the preferred method of rectification because it conserves all of the signal energy for analysis. Half-wave rectification discards the portion of the EMG signal that is below the baseline. In doing so,

8840-462: The active muscle directly below the surface decreased. As adipose tissue increased, the amplitude of the surface EMG signal directly above the center of the active muscle decreased. EMG signal recordings are typically more accurate with individuals who have lower body fat, and more compliant skin, such as young people when compared to old. Muscle cross talk occurs when the EMG signal from one muscle interferes with that of another limiting reliability of

8970-754: The affected extremity, namely venipuncture, to prevent development or worsening of lymphedema or cellulitis. Despite the potential risk, the evidence for such complications subsequent to venipuncture is limited. No published reports exist of cellulitis, infection, or other complications related to EMG performed in the setting of lymphedema or prior lymph node dissection. However, given the unknown risk of cellulitis in patients with lymphedema, reasonable caution should be exercised in performing needle examinations in lymphedematous regions to avoid complications. In patients with gross edema and taut skin, skin puncture by needle electrodes may result in chronic weeping of serous fluid. The potential bacterial media of such serous fluid and

9100-426: The ages of 20 and 40. This is often a person's first reason to see a medical professional as an adult. Recurrent episodes occur in more than half of people with the repeated episodes being generally more painful than the first. Other problems may occur along with low back pain. Chronic low back pain is associated with sleep problems, including a greater amount of time needed to fall asleep, disturbances during sleep,

9230-614: The average of the data is no longer zero therefore it can be used in statistical analyses. Needle EMG used in clinical settings has practical applications such as helping to discover disease. Needle EMG has limitations, however, in that it does involve voluntary activation of muscle, and as such is less informative in patients unwilling or unable to cooperate, children and infants, and in individuals with paralysis. Surface EMG can have limited applications due to inherent problems associated with surface EMG. Adipose tissue (fat) can affect EMG recordings. Studies show that as adipose tissue increased

9360-399: The back of the spine, and are important for keeping the spine straight and stable during many common movements such as sitting, walking and lifting. A problem with these muscles is often found in someone with chronic low back pain, because the back pain causes the person to use the back muscles improperly in trying to avoid the pain. The problem with the multifidus muscles continues even after

9490-409: The body's tissues. There are four main stages: transduction , transmission, perception , and modulation . The nerve cells that detect pain have cell bodies located in the dorsal root ganglia and fibers that transmit these signals to the spinal cord. The process of pain sensation starts when the pain-causing event triggers the endings of appropriate sensory nerve cells . This type of cell converts

9620-510: The body, but also a person's social and economic status. It would be greatly beneficial for people with CNSLBP to be screened for genetic issues, unhealthy lifestyles and habits, and psychosocial factors on top of musculoskeletal issues. Chronic lower back pain is defined as back pain that lasts more than three months. The symptoms of low back pain usually improve within a few weeks from the time they start, with 40–90% of people recovered by six weeks. Normal activity should be continued as much as

9750-545: The care that most people with low back pain receive globally. This is due to factors such as availability, access and payment models (e.g. insurance, health-care systems). Increasing general physical activity has been recommended, but no clear relationship to pain or disability or returning to work has been found when used for the treatment of an acute episode of pain. For acute pain, low- to moderate-quality evidence supports walking. Aerobic exercises like progressive walking appears useful for subacute and acute low back pain,

9880-516: The conducting function of nerves. This is called nerve conduction study (NCS). Needle EMG and NCSs are typically indicated when there is pain in the limbs, weakness from spinal nerve compression , or concern about some other neurologic injury or disorder. Spinal nerve injury does not cause neck, mid back pain or low back pain , and for this reason, evidence has not shown EMG or NCS to be helpful in diagnosing causes of axial lumbar pain, thoracic pain, or cervical spine pain . Needle EMG may aid with

10010-468: The cost, and on how accessible acupuncture is for the person. Massage therapy does not appear to provide much benefit for acute low back pain. Massage therapy has been found to be more effective for acute low back pain than no treatment; the benefits were found to be limited to the short term and there was no effect for improving function. For chronic low back pain, massage therapy was no better than no treatment for both pain and function, though only in

10140-430: The delay between the contractions of individual muscle fibers within a motor unit and is a sensitive test for dysfunction of the neuromuscular junction caused by drugs, poisons, or diseases such as myasthenia gravis. The technique is complicated and typically performed only by individuals with special advanced training. Surface EMG is used in a number of settings; for example, in the physiotherapy clinic, muscle activation

10270-408: The diagnosis of nerve compression or injury (such as carpal tunnel syndrome ), nerve root injury (such as sciatica), and with other problems of the muscles or nerves. Less common medical conditions include amyotrophic lateral sclerosis , myasthenia gravis , and muscular dystrophy . The first step before insertion of the needle electrode is skin preparation. This typically involves simply cleaning

10400-478: The diagnosis of specific neuromuscular diseases. EMGs may be useful for additional study of fatigue associated with post-poliomyelitis syndrome and electromechanical function in myotonic dystrophy (level C rating, class III data). Recently, with the rise of technology in sports, sEMG has become an area of focus for coaches to reduce the incidence of soft tissue injury and improve player performance. Certain US states limit

10530-403: The discs between the vertebrae or a spinal disc herniation , broken vertebra(e) (such as from osteoporosis ) or, rarely, an infection or tumor of the spine. Women may have acute low back pain from medical conditions affecting the female reproductive system, including endometriosis , ovarian cysts , ovarian cancer , or uterine fibroids . Nearly half of all pregnant women report pain in

10660-405: The discs have not been found to be effective in those with persistent, non-radiating pain; however, they may be considered for those with persistent sciatic pain. Epidural corticosteroid injections provide a slight and questionable short-term improvement in those with sciatica but are of no long-term benefit. There are also concerns of potential side effects. Surgery may be useful in those with

10790-593: The effects of general exercises. The most effective types of exercise to improve low back pain symptoms are core strengthening and mixed exercise types. An appropriate type of exercise recommended is an aerobic exercise program for 12 hours of exercise over a duration of 8 weeks. Distress due to low back pain contributes significantly to overall pain and disability experienced. Therefore, treatment strategies that aim to change beliefs and behaviours, such as cognitive-behavioural therapy can be of use. Access to care as recommended in medical guidelines varies considerably from

10920-418: The electromyographer assess the activity of muscle during voluntary contraction. The shape, size, and frequency of the resulting electrical signals are judged. Then the electrode is retracted a few millimetres, and again the activity is analyzed. This is repeated, sometimes until data on 10–20 motor units have been collected in order to draw conclusions about motor unit function. Each electrode track gives only

11050-419: The event into an electrical signal by transduction. Several different types of nerve fibers carry out the transmission of the electrical signal from the transducing cell to the posterior horn of spinal cord , from there to the brain stem , and then from the brain stem to the various parts of the brain such as the thalamus and the limbic system . In the brain, the pain signals are processed and given context in

11180-537: The first (1966) practitioners to use sEMG. In the early 1980s, Cram and Steger introduced a clinical method for scanning a variety of muscles using an EMG sensing device. Research began at the Mayo Clinic in Rochester, Minnesota under the guidance of Edward H. Lambert , MD, PhD (1915–2003) in the early 1950s. Lambert, known as the "Father of EMG", with the assistance of his Research Technician, Ervin L Schmidt,

11310-406: The following medical conditions (please note this is not an exhaustive list of conditions that can result in abnormal EMG studies): Disorders of muscle: Disorders of the neuromuscular junction: Disorders of nerves: Plexus disorders: Root disorders: Motor neuron disease The first documented experiments dealing with EMG started with Francesco Redi 's works in 1666. Redi discovered

11440-418: The irritation of needle insertion subsides, the electromyograph should detect no abnormal spontaneous activity (i.e., a muscle at rest should be electrically silent, with the exception of the area of the neuromuscular junction , which is, under normal circumstances, very spontaneously active). When the muscle is voluntarily contracted, action potentials begin to appear. As the strength of the muscle contraction

11570-520: The laryngeal muscles, and subspecialists in urology, obstetrics and gynecology who have had selective training in performing EMG of muscles controlling bowel and bladder function. One basic function of EMG is to see how well a muscle can be activated. The most common way that can be determined is by performing a maximal voluntary contraction (MVC) of the muscle that is being tested. Each muscle group type has different characteristics, and MVC positions are varied for different muscle group types. Therefore,

11700-432: The latter also improved muscle endurance and strength, whilst concurrently decreased self-reported disability. Aquatic therapy is recommended as an option in those with other preexisting conditions like extreme obesity , degenerative joint disease , or other conditions that limit progressive walking. Aquatic therapy is recommended for chronic and subacute low back pain in those with a preexisting condition. Aquatic therapy

11830-874: The limits of pain. Providing individuals with coping skills through reassurance of these facts is useful in speeding recovery. For those with sub-chronic or chronic low back pain, multidisciplinary treatment programs may help. Initial management with non–medication based treatments is recommended Non–medication based treatments include superficial heat , massage , acupuncture , or spinal manipulation . If these are not sufficiently effective, NSAIDs are recommended. Acetaminophen and systemic steroids are not recommended as both medications are not effective at improving pain outcomes in acute or subacute low back pain. Physical therapy stabilization exercises for lumbar spine and manual therapy have shown decrease in pain symptoms in patients. Manual therapy and stabilization effects have similar effects on low back pain which overweighs

11960-436: The low back during pregnancy, due to changes in their posture and center of gravity causing muscle and ligament strain. Low back pain can be broadly classified into four main categories: The lumbar (or lower back) region is the area between the lower ribs and gluteal fold which includes five lumbar vertebrae (L1–L5) and the sacrum. In between these vertebrae are fibrocartilaginous discs , which act as cushions, preventing

12090-439: The mental health for those with chronic low back pain. It also improves long-term function and appears to reduce recurrence rates for as long as six months after the completion of the program. The observed treatment effect for the exercise when compared to no treatment, usual care or placebo, improved pain (low‐certainty evidence), but improvements were small for functional limitations outcomes (moderate‐certainty evidence). There

12220-535: The more body fat an individual has, the weaker the EMG signal. When placing the EMG sensor, the ideal location is at the belly of the muscle: the longitudinal midline. The belly of the muscle can also be thought of as in-between the motor point (middle) of the muscle and the tendonus insertion point. Cardiac pacemakers and implanted cardiac defibrillators (ICDs) are used increasingly in clinical practice, and no evidence exists indicating that performing routine electrodiagnostic studies on patients with these devices pose

12350-476: The most common reasons people visit doctors. For pain that has lasted only a few weeks, the pain is likely to subside on its own. Thus, if a person's medical history and physical examination do not suggest a specific disease as the cause, medical societies advise against imaging tests such as X-rays , CT scans , and MRIs . Individuals may want such tests but, unless red flags are present, they are unnecessary health care . Routine imaging increases costs,

12480-399: The movements or upon waking up the following morning. The description of the symptoms may range from tenderness at a particular point, to diffuse pain. It may or may not worsen with certain movements, such as raising a leg, or positions, such as sitting or standing. Pain radiating down the legs (known as sciatica ) may be present. The first experience of acute low back pain is typically between

12610-409: The muscle under observation. Typical repetition rate of muscle motor unit firing is about 7–20 Hz, depending on the size of the muscle (eye muscles versus seat (gluteal) muscles), previous axonal damage and other factors. Damage to motor units can be expected at ranges between 450 and 780 mV. Muscle tissue at rest is normally electrically inactive. After the electrical activity caused by

12740-400: The muscle. Normal muscles exhibit a brief burst of muscle fiber activation when stimulated by needle movement, but this rarely lasts more than 100ms. The two most common pathologic types of resting activity in muscle are fasciculation and fibrillation potentials. A fasciculation potential is an involuntary activation of a motor unit within the muscle, sometimes visible with the naked eye as

12870-428: The name ErMel Inc. It was not until the middle of the 1980s that integration techniques in electrodes had sufficiently advanced to allow batch production of the required small and lightweight instrumentation and amplifiers. At present, a number of suitable amplifiers are commercially available. In the early 1980s, cables that produced signals in the desired microvolt range became available. Recent research has resulted in

13000-497: The optimal dose and length of treatment is unclear. As of 2022, the CDC has released a guideline for prescribed opioid use in the management of chronic pain. It states that opioid use is not the preferred treatment when managing chronic pain due to the excessive risks involved, including high risks of addiction, accidental overdose and death. Specialist groups advise against general long-term use of opioids for chronic low back pain. If

13130-411: The outside of the disc. Specialized cells that can survive without direct blood supply are in the inside of the disc. Over time, the discs lose flexibility and the ability to absorb physical forces. This decreased ability to handle physical forces increases stresses on other parts of the spine, causing the ligaments of the spine to thicken and bony growths to develop on the vertebrae. As a result, there

13260-529: The overall number of individuals affected expected to increase as the population ages. According to the World Health Organizations, lower back pain is the top medical condition world-wide from which the most number of people world-wide can benefit from improved rehabilitation. In the common presentation of acute low back pain, pain develops after movements that involve lifting, twisting, or forward-bending. The symptoms may start soon after

13390-540: The pacemaker. Despite such concerns, no immediate or delayed adverse effects have been reported with routine NCS. No known contraindications exist for performing needle EMG or NCS on pregnant patients. Additionally, no complications from these procedures have been reported in the literature. Evoked potential testing, likewise, has not been reported to cause any problems when it is performed during pregnancy. Patients with lymphedema or patients at risk for lymphedema are routinely cautioned to avoid percutaneous procedures in

13520-924: The pain allows. Initial management with non-medication based treatments is recommended. Non–medication based treatments include superficial heat , massage , acupuncture , or spinal manipulation . If these are not sufficiently effective, NSAIDs are recommended. A number of other options are available for those who do not improve with usual treatment. Opioids may be useful if simple pain medications are not enough, but they are not generally recommended due to side effects, including high rates of addiction, accidental overdose and death. Surgery may be beneficial for those with disc-related chronic pain and disability or spinal stenosis . No clear benefit of surgery has been found for other cases of non-specific low back pain. Low back pain often affects mood, which may be improved by counseling or antidepressants . Additionally, there are many alternative medicine therapies, but there

13650-461: The pain does not go away with conservative treatment or if it is accompanied by "red flags" such as unexplained weight loss, fever , or significant problems with feeling or movement, further testing may be needed to look for a serious underlying problem. In most cases, imaging tools such as X-ray computed tomography are not useful or recommended for low back pain that lasts less than 6 weeks (with no red flags) and carry their own risks. Despite this,

13780-426: The pain goes away, and is probably an important reason why the pain comes back. Teaching people with chronic low back pain how to use these muscles is recommended as part of a recovery program. An intervertebral disc has a gelatinous core surrounded by a fibrous ring . When in its normal, uninjured state, most of the disc is not served by either the circulatory or nervous systems – blood and nerves only run to

13910-414: The pain is not managed adequately, short-term use of opioids such as morphine may be suggested, although low back pain outcomes are poorer in the long-term. If prescribed, a person and their clinician should have a realistic plan to discontinue its use in the event that the risks outweigh the benefit. These medications carry a risk of addiction, may have negative interactions with other drugs, and have

14040-430: The pain modulation mechanisms may not function properly. These phenomena are involved in chronic pain. As the structure of the low back is complex, the reporting of pain is subjective , and is affected by social factors, the diagnosis of low back pain is not straightforward. While most low back pain is caused by muscle and joint problems, this cause must be separated from neurological problems, spinal tumors, fracture of

14170-659: The patient can be cooperative, the type of needle electrode used to study the patient, and sampling error in terms of the number of areas studied within a single muscle and the number of muscles studied overall. Interpreting EMG findings is usually best done by an individual informed by a focused history and physical examination of the patient, and in conjunction with the results of other relevant diagnostic studies performed including most importantly, nerve conduction studies, but also, where appropriate, imaging studies such as MRI and ultrasound, muscle and nerve biopsy, muscle enzymes, and serologic studies. Abnormal results may be caused by

14300-421: The peak EMG measure when assessing core exercises." Providing the reader with both sets of data would result in enhanced validity of the study and potentially eradicate the contradictions within the research. EMG can also be used for indicating the amount of fatigue in a muscle. The following changes in the EMG signal can signify muscle fatigue : an increase in the mean absolute value of the signal, increase in

14430-528: The performance of needle EMG by nonphysicians. New Jersey declared that it cannot be delegated to a physician's assistant. Michigan has passed legislation saying needle EMG is the practice of medicine. Special training in diagnosing medical diseases with EMG is required only in residency and fellowship programs in neurology, clinical neurophysiology, neuromuscular medicine, and physical medicine and rehabilitation. There are certain subspecialists in otolaryngology who have had selective training in performing EMG of

14560-549: The presence of cancer is a history of the same. With other causes ruled out, people with non-specific low back pain are typically treated symptomatically, without exact determination of the cause. Efforts to uncover factors that might complicate the diagnosis, such as depression, substance abuse, or an agenda concerning insurance payments may be helpful. Imaging is indicated when there are red flags, ongoing neurological symptoms that do not resolve, or ongoing or worsening pain. In particular, early use of imaging (either MRI or CT)

14690-431: The process of pain perception . Through modulation, the brain can modify the sending of further nerve impulses by decreasing or increasing the release of neurotransmitters . Parts of the pain sensation and processing system may not function properly; creating the feeling of pain when no outside cause exists, signaling too much pain from a particular cause, or signaling pain from a normally non-painful event. Additionally,

14820-471: The recording of deeper muscles. Single fiber EMG needle electrodes are designed to have very tiny recording areas, and allow for the discharges of individual muscle fibers to be discriminated. To perform intramuscular EMG, typically either a monopolar or concentric needle electrode is inserted through the skin into the muscle tissue. The needle is then moved to multiple spots within a relaxed muscle to evaluate both insertional activity and resting activity in

14950-410: The recording which can be highly variable depending on the weight of a patient, and cannot reliably discriminate between the discharges of adjacent muscles. Specific electrode placements and functional tests have been developed to minimize this risk, thus providing reliable examinations. Intramuscular EMG can be performed using a variety of different types of recording electrodes. The simplest approach

15080-462: The reference electrode. The exposed tip of the fine wire serves as the active electrode. As a result of this configuration, signals tend to be smaller when recorded from a concentric electrode than when recorded from a monopolar electrode and they are more resistant to electrical artifacts from tissue and measurements tend to be somewhat more reliable. However, because the shaft is exposed throughout its length, superficial muscle activity can contaminate

15210-502: The researcher should be very careful while choosing the MVC position type to elicit the greater muscle activity level from the subjects. The types of MVC positions can vary among muscle types, contingent upon the specific muscle group being considered, including trunk muscles, lower limb muscles, and others. Muscle force, which is measured mechanically, typically correlates highly with measures of EMG activation of muscle. Most commonly this

15340-473: The result of non-serious muscle or skeletal issues such as sprains or strains . Obesity, smoking, weight gain during pregnancy, stress , poor physical condition, and poor sleeping position may also contribute to low back pain. There is no consensus as to whether spinal posture or certain physical activities are causal factors. A full list of possible causes includes many less common conditions. Physical causes may include osteoarthritis , degeneration of

15470-421: The same time as an EMG to diagnose neurological diseases. Some patients can find the procedure somewhat painful, whereas others experience only a small amount of discomfort when the needle is inserted. The muscle or muscles being tested may be slightly sore for a day or two after the procedure. EMG signals are essentially made up of superimposed motor unit action potentials (MUAPs) from several motor units. For

15600-411: The short-term. The overall quality of the evidence was low and the authors conclude that massage therapy is generally not an effective treatment for low back pain. Massage therapy is recommended for selected people with subacute and chronic low back pain, but it should be paired with another form of treatment like aerobic or strength exercises. For acute or chronic radicular pain syndromes massage therapy

15730-508: The signal of the muscle being tested. Surface EMG is limited due to lack of deep muscles reliability. Deep muscles require intramuscular wires that are intrusive and painful in order to achieve an EMG signal. Surface EMG can measure only superficial muscles and even then it is hard to narrow down the signal to a single muscle. The electrical source is the muscle membrane potential of about –90 mV. Measured EMG potentials range between less than 50 μV and up to 30 mV, depending on

15860-456: The skin with an alcohol pad. The actual placement of the needle electrode can be difficult and depends on a number of factors, such as specific muscle selection and the size of that muscle. Proper needle EMG placement is very important for accurate representation of the muscle of interest, although EMG is more effective on superficial muscles as it is unable to bypass the action potentials of superficial muscles and detect deeper muscles. Also,

15990-798: The spine, and infections, among others. The ICD 10 code for low back pain is M54.5. There are a number of ways to classify low back pain with no consensus that any one method is best. There are three general types of low back pain by cause: mechanical back pain (including nonspecific musculoskeletal strains, herniated discs , compressed nerve roots , degenerative discs or joint disease , and broken vertebra), non-mechanical back pain ( tumors , inflammatory conditions such as spondyloarthritis , and infections), and referred pain from internal organs ( gallbladder disease , kidney stones , kidney infections , and aortic aneurysm , among others). Mechanical or musculoskeletal problems underlie most cases (around 90% or more), and of those, most (around 75%) do not have

16120-457: The title EMG . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=EMG&oldid=1256502872 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Electromyography EMG testing has

16250-408: The treatment. There is often improvement within the first month. Although fear in those suffering from low back pain often leads to avoiding activity, this is found to lead to greater disability. The recommendations include remaining active, avoiding activity that worsen the pain, and understanding self-care of the symptoms. Management of low back pain depends on which of the three general categories

16380-416: The underlying cause as either mechanical, non-mechanical, or referred pain . The symptoms of low back pain usually improve within a few weeks from the time they start, with 40–90% of people recovered by six weeks. In most episodes of low back pain a specific underlying cause is not identified or even looked for, with the pain believed to be due to mechanical problems such as muscle or joint strain . If

16510-436: The use of imaging in low back pain has increased. Some low back pain is caused by damaged intervertebral discs , and the straight leg raise test is useful to identify this cause. In those with chronic pain, the pain processing system may malfunction, causing large amounts of pain in response to non-serious events. Chronic non-specific low back pain (CNSLBP) is a highly prevalent musculoskeletal condition that not only affects

16640-457: The vertebrae from rubbing together while at the same time protecting the spinal cord . Nerves come from and go to the spinal cord through specific openings between the vertebrae, receiving sensory input and sending messages to muscles. Stability of the spine is provided by the ligaments and muscles of the back and abdomen. Small joints called facet joints limit and direct the motion of the spine. The multifidus muscles run up and down along

16770-416: The violation of skin integrity may increase the risk of cellulitis. Before proceeding, the physician should weigh the potential risks of performing the study with the need to obtain the information gained. There are two kinds of EMG: surface EMG and intramuscular EMG. Surface EMG assesses muscle function by recording muscle activity from the surface above the muscle on the skin. Surface EMG can be recorded by

16900-507: Was also possible to record electrical activity during a voluntary muscle contraction. The first actual recording of this activity was made by Marey in 1890, who also introduced the term electromyography. In 1922, Gasser and Erlanger used an oscilloscope to show the electrical signals from muscles. Because of the stochastic nature of the myoelectric signal, only rough information could be obtained from its observation. The capability of detecting electromyographic signals improved steadily from

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