When your muscles are sore or weak, and you don’t know why there are two tests (EMG & NCS) that can help give you answers.
Physicians can use the results of these tests to figure out whether you have a muscular problem or a nerve problem.
Electromyography (EMG) is performed using an instrument called an electromyograph, to produce a record called an electomyogram. An electromyograph detects the electrical potential generated by muscle cells when these cells are electrically or neurologically activated. The signals can be analyzed to detect medical abnormalities, activation level, recruitment order or to analyze the biomechanics of movement.
Common indications for EMG are:
- Radiculopathy commonly known as “back/neck pinched nerve”, sciatica
- Neuropathy usually manifested by burning pain, numbness and/or tingling
- Brachial or lumbosacral plexus injury
- Muscle diseases such myopathies like muscular dystrophy
- Motor neuron disease such as amyotrophic lateral sclerosis (ALS)
- Post polio syndrome
- Myotonic muscular dystrophy
- Polymyositis / Dermatomyositis
Nerve Conduction Studies
A nerve conduction study (NCS) shows how well signals travel along large nerve fibers and can help find the cause of abnormal nerve function. To perform a study, a physician (or trained technologist working under a physician supervision) applies small electric pulses to a nerve. The pulses cause the patient to feel a mild tingling sensation; and if the muscle is stimulated, it will move. The type of problem being evaluated determines how many nerves are tested.
Common indications for NCS are:
- Carpal tunnel syndrome
- Ulnar neuropathy such as cubital tunnel syndrome
- Tarsal tunnel syndrome
- Peripheral neuropathy
- Hereditary neuropathies like Charcot Marie Tooth
- Brachial/lumbosacral plexopathy
- Myasthenia Gravis
- Guillain Barre syndrome (AIDP)
- Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)
Preparation for test: When scheduling appointment notify is you are taking any anticoagulation therapy and if you have cardiac pacemaker / defibrillator or spinal cord stimulator. The day of test you can take your regular medications, no need to fast; and do not apply any body / hand lotion or cream.