Normal Values:

Muscle tissue is normally electrically silent at rest. Once the muscles quiet down after the needles are inserted, there should be little muscle cell electrical activity noted on the screen.

When the muscle is voluntarily contracted, activity begins to appear. As contraction is increased, more and more muscle fibers produce action potentials until a disorderly group of action potentials of varying rates and amplitudes (complete recruitment and interference pattern) appears with full contraction.

What abnormal results mean:

Disorders or conditions that cause abnormal results include the following:

• Alcoholic neuropathy
• Amyotrophic lateral sclerosis (ALS)
• Axillary nerve dysfunction
• Becker's muscular dystrophy
• Brachial plexopathy
• Carpal tunnel syndrome
• Cervical spondylosis
• Common peroneal nerve dysfunction
• Denervation (reduced nervous stimulation)
• Dermatomyositis
• Distal median nerve dysfunction
• Duchenne muscular dystrophy
• Facioscapulohumeral muscular dystrophy (Landouzy-Dejerine)
• Familial periodic paralysis
• Femoral nerve dysfunction
• Friedreich's ataxia
• Guillain-Barre
• Lambert-Eaton Syndrome
• Mononeuritis multiplex
• Mononeuropathy
• Myopathy (muscle degeneration caused by a number of disorders, including muscular dystrophy)
• Myasthenia gravis
• Peripheral neuropathy
• Polymyositis
• Radial nerve dysfunction
• Sciatic nerve dysfunction
• Sensorimotor polyneuropathy
• Shy-Drager syndrome
• Thyrotoxic periodic paralysis
• Tibial nerve dysfunction
• Ulnar nerve dysfunction