Electro-Diagnostic Studies

Electromyography (EMG) and Nerve Conduction Studies (NCS)

Electro-diagnostic studies such as an electromyogram (EMG) and nerve conduction study (NCS) are procedures that evaluate the health of the muscles and nerves (motor neurons) that control them. Motor neurons are nerve cells that transmit electrical signals from the brain and spinal cord to the muscles and cause the muscles to relax and contract. This transmission allows for movement of the muscles.

AVORS Medical Group and Dr. Orlando Pena offer special diagnostic testing called Electromyography (EMG) and nerve conduction studies (NCS). Below you'll find valuable information on EMG and NCS. For more information contact us in Valencia, CA (661) 705-5100 or Lancaster, CA (661) 726-5005.

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Nerve Conduction

An NCS is part of an electromyogram study and is performed prior to the EMG. This study uses electrode stickers applied to the skin to evaluate how well the motor neurons communicate with the muscle.

Electromyography

Following an NCS, an EMG is then performed. The doctor will clean the desired areas of the skin with an antiseptic. Then a needle electrode is inserted into the muscle tissue. Slight discomfort may result while the needle is being inserted. The electrode measures how well it responds to those signals and records the electrical activity in that muscle when it is contracted and when at rest. The electrodes translate the electrical activity into graphs, sounds or numerical values that are interpreted by the doctor. The findings of an EMG study can reveal nerve dysfunction, muscle dysfunction or problems with nerve-to-muscle transmission.

An EMG and NCS are procedures commonly performed in a medical office setting. The patient lies down on an examination table or reclined chair to perform the study. The doctor may have the patient move into different positions during the study. When the studies are completed the electrodes will be removed. The study can take from 30 to 60 minutes depending on how many extremities are being tested.

Reasons For Testing

An EMG/NCS may help diagnose a muscle or nerve disorder and may be ordered for the following:

Tingling
Numbness
Muscle weakness, atrophy, pain, cramping
Paralysis
Involuntary muscle twitching

Possible Underlying Diagnoses

Some causes that an EMG/NCS may detect are as follows:

Muscle disorders (e.g. muscular dystrophy)
Radiculopathies
Motor neuron disorders (e.g. myasthenia gravis)
Peripheral nerve disorders (e.g. carpal tunnel syndrome)
Major nerve disorders (e.g. Amyotrophic Lateral Sclerosis / ALS)

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What is an Electromyogram (EMG) with nerve conduction study (NCS)?

EMG with NCS is a form of electrodiagnostic testing performed at AVORS MEDICAL GROUP used to study nerve and muscle function. It is commonly performed by a physiatrist (a physician trained in physical medicine and rehabilitation) who has been trained extensively in interpretation of the data collected from these diagnostic studies. An EMG with NCS test is often described as an extension of the physician’s examination and can provide additional details regarding the health of particular nerves, especially those prone to compression at certain places along their natural course in our bodies.

How are the EMG and NCS performed?

The EMG and NCS are essentially two halves of a complete electrodiagnostic study.

During an EMG, a small pin is used to record electrical signals that our muscles and nerves put out during normal activity. Within the fibers of the muscles, there is “chatter” between the nerve endings and each muscle fiber, and the trained physician essentially “listens in on the conversation” between the muscles and nerves.

During the NCS, small recording electrodes are taped to the surface of the skin while a small external electric impulse is applied to the skin overlying a nerve. This impulse travels a given distance along the course of the nerve in a certain amount of time which is accurately recorded down to the hundredth of a millisecond! The velocity of the impulse along with other data points are interpreted and can shed light on various abnormalities if and when present.
Why does AVORS Medical Group offer NCS/EMG testing?

An EMG/NCS is often performed when patients have unexplained symptoms such as numbness, tingling, weakness, or radiating pain in their arms or legs. These symptoms when present alongside neck pain and/or lower back pain may indicate nerve compression at these anatomic locations or could also indicate entrapment of nerves further along their course such as at the elbow, wrist, or knee. This test may also be helpful in localizing the anatomic location of nerve injury following an accident. By further understanding what is causing these symptoms, doctors are able to provide treatment that is more accurate and targeted for success.
What is an EMG/NCS test used to diagnose?
Conditions that EMG/NCS testing helps diagnose include:
- Carpal tunnel syndrome
- Cubital tunnel syndrome
- Radiculopathy
- Generalized Peripheral Neuropathies
- Muscle diseases
- ALS (Lou Gehrig’s disease)
- Myasthenia gravis
Medical Providers will also order testing if you experience any of the following symptoms:
- Numbness
- Decreased sensation
- Tingling or frequent feeling of "pins and needles"
- Radiating pain or burning sensation into arms or legs
- Muscle spasms or weakness
- Difficulty performing daily tasks such as walking, buttoning clothes or handling objects
Are any risks involved in this procedure?

EMG’s are considered low risk procedures. The procedure lasts around 30-60 minutes and is performed by a skilled practitioner. AVORS has Dr. Orlando Pena, who trained under a well-recognized expert in the field of electrodiagnostic medicine at the University of Texas at San Antonio. He has performed many hundreds of EMG/NCS in his residency training alone. You are in skilled hands.
AVORS MEDICAL GROUP EMG/NCS preparations
- Take a shower or bath shortly before your exam in order to remove oils from your skin.
- Don't apply lotions or creams to your arms or legs before the exam.
- Tell your provider any important personal or family history such as if you:
1. Have a pacemaker or any other electrical medical device
2. Take blood-thinning medications
3. Have hemophilia, a blood-clotting disorder that causes prolonged bleeding
4. Have ever had a negative reaction to nerve conduction studies in the past
What happens after the procedure?

The physiatrist will interpret the results of your exam and prepare a report with the electrodiagnostic impression. Your primary care provider or the medical provider who ordered the test will discuss the report with you at the appropriate follow-up appointment.

AVORS Medical Group is proud to offer premier Interventional Pain Management services to our patients in California. We are able to provide this service because our providers are board certified Board Certified in Physical Medicine & Rehabilitation (PM&R), and highly rated in Pain Management. Interventional Pain Management providers deliver minimally invasive treatments that can help patients take back their lives and dramatically reduce pain.

Dr. Orlando Pena is a Doctor of Osteopathic Medicine (DO), Board Certified in Physical Medicine & Rehabilitation (PM&R) and performs minimally invasive EMG/NCS testing.