ELECTROMYOGRAMS OR EMG

Electromyogram Testing

Sometimes, our Southwest Scoliosis and Spine Institute doctors, Richard Hostin, MD, Devesh Ramnath, MD, Ishaq Syed, MD, Shyam Kishan, MD, and Kathryn Wiesman, MD, will need to order extra testing to diagnose or help devise a treatment plan. Because of this, the doctor may order an electromyogram or EMG.  The doctor will then look at the nerve roots to determine their working condition.

Electromyogram (EMG) testing provides a valuable diagnostic procedure to assess the function of muscles and the nerves that control them. It provides a non-invasive or minimally invasive technique that provides valuable insights into various neuromuscular conditions. This webpage provides an overview of EMG testing, including its procedure, uses, benefits, and what to expect during the examination.

Reason to conduct an EMG Test?

By looking for abnormal electrical signals in the muscles, an EMG can show nerves being irritated or pinched as they leave the spine to the arm or leg.  As an example, an EMG can be compared to a test of the wiring of a lamp. If a working bulb lights up, you can assume that the wiring works. If the bulb does not light up you can assume that the wiring needs attention.  As an example, the lamp could be unplugged or short-circuited.  Using the muscles like the light bulb, the EMG determines the condition of the nerves that supply those muscles.  Just like the wiring on the lamp.  If the EMG finds muscles working improperly, the doctor will infer that a pinched or damaged nerve exists.  

Understanding EMG Testing

EMG testing involves the measurement and recording of electrical activity in the muscles and the nerves that control them. A skilled technician or doctor such as a neurologist, physiatrist, or electromyographer will conduct the procedure.  EMG testing consists of two main components:

• Needle Electromyography (EMG): Fine needle electrodes get inserted into specific muscles to measure their electrical activity at rest and during contraction. The EMG can assess muscle function, detect abnormal patterns of electrical activity, and help identify muscle or nerve disorders.
• Nerve Conduction Studies (NCS): NCS measures the speed and strength of electrical signals as they travel along the nerves. The person conducting the test will place electrodes on the skin over the nerves.  Then, small electrical pulses are generated to stimulate the nerves. The response is then recorded, evaluating nerve health and identifying any abnormalities or damage.

In short, an electromyogram (EMG) looks at the function of the nerve roots leaving the spine.  In addition, it does this by looking at how well the electrical currents in the nerves are transmitted to the muscles. Also, pressure on the nerves or damage to the nerves changes the way they transmit electrical current. This shows up in the muscles from the information being sent to them from the brain by the nerves. When using electrical tests to diagnose spine problems, an EMG works with another test that identifies electrical signals going from the body to the brain.  Doctors refer to these as somatosensory evoked potentials (SSEPs).

Uses of EMG Testing

EMG testing is utilized in various clinical scenarios to aid in the diagnosis, evaluation, and management of several neuromuscular conditions, including:

• Peripheral Nerve Disorders: EMG testing can help diagnose conditions such as carpal tunnel syndrome, ulnar neuropathy, or peripheral neuropathies. This occurs by assessing the extent of nerve damage and guiding treatment decisions.
• Muscle Disorders: EMG can assist in identifying muscle disorders like muscular dystrophy, myopathies, or myasthenia gravis. It can evaluate muscle function, detect abnormal electrical patterns, and assess disease progression.
• Nerve Root Disorders: EMG testing can help determine the presence and severity of nerve root compression or radiculopathy, such as herniated discs or spinal stenosis.
• Motor Neuron Diseases: EMG can aid in diagnosing conditions like amyotrophic lateral sclerosis (ALS) by assessing the function of motor neurons and detecting abnormalities.

Benefits of EMG Testing

EMG testing provides several benefits in the diagnosis and management of neuromuscular disorders:

• Accurate Diagnosis: EMG testing can help differentiate between muscle and nerve disorders, contributing to a more accurate diagnosis. This enables healthcare professionals to develop targeted treatment plans and interventions.
• Evaluation of Treatment Effectiveness: EMG testing can monitor the progression of a condition and assess the effectiveness of various treatments.  These include medications, physical therapy, or surgical interventions.
• Proactive Management: EMG testing can identify early signs of muscle or nerve dysfunction.  This allows for early intervention and proactive management to prevent further damage or complications.
• Patient Education: EMG testing can provide patients with a better understanding of their condition, its underlying mechanisms, and potential treatment options. This knowledge empowers individuals to actively participate in their own care and make informed decisions.

Limitations of the EMG

An EMG does not show why the problem occurred or what caused it. The test looks primarily at how the muscles react to the nerve problem. However, a problem in the nerve could exist anywhere between the spine and the muscle.  Also, the location may not necessarily occur in the spine.  Still, an EMG helps to determine the damage to a nerve and if a herniated disc or another problem puts pressure on the nerve roots. Also, the test may appear normal when a damaged nerve exists.  This refers to what doctors call a “false negative,” meaning the test results look negative, even though actually positive.

Risks Associated with an EMG

EMGs do have a small amount of risks associated with them.  For instance, anytime a doctor inserts a needle into the body, a small chance of infection will exist. However, the risk is really small with an EMG test.

Conclusion

Electromyogram (EMG) testing provides a valuable diagnostic tool that helps evaluate muscle and nerve function, aiding in the diagnosis and management of various neuromuscular disorders. Therefore, by assessing electrical activity in muscles and the conduction of nerve signals, Finally, EMG testing provides valuable insights for healthcare professionals to make accurate diagnoses and develop appropriate treatment plans. When one of our doctors at the Southwest Scoliosis and Spine Institute recommends EMG testing, we will discuss the procedure with the patient regarding its potential benefits and concerns regarding our comprehensive neuromuscular health evaluation. If you are having back pain, please give us a call and make an appointment at one of our offices in Dallas, Plano, and Frisco, Texas.