Neuropathy (nerve damage) is the primary disorder that may be diagnosed by a nerve conduction velocity (NCV) test. The type of nerve damage involved may include:

• Pinched nerves or nerve root compression.
  
  
• Trauma to nerves. An example is plexopathy, which involves injury or disorder of a nerve plexus (network).
  
  
• Neuritis. Inflammation of a nerve or group of nerves.
  
  
• Demyelination. Destruction of the myelin sheath
  
  
• Axonopathy. Damage to the axon (nerve fiber).
  
  
• Conduction block. Blockage of the electrical impulse somewhere along the nerve pathway.

Nerve damage may be caused by a variety of conditions and diseases, including diabetes, physical pressure on nerves (compression neuropathy), tumors, damage to blood vessels, autoimmune disorders, stroke and physical injury (e.g., head injury, spinal cord injury).

In addition, many different neurological conditions can cause nerve damage, including carpal tunnel syndrome, amyotrophic lateral sclerosis (Lou Gehrig’s disease), multiple sclerosis, Guillain-Barre syndrome and Charcot-Marie-Tooth disease.

In most cases, a NCV test is performed in conjunction with an electromyography (EMG). These two tests may be used to confirm suspected neuromuscular disorders, such as:

• Myopathy. Disease of muscle or muscle tissue. Muscular dystrophy is one of the most common groups of myopathies.
  
  
• Myositis. Inflammation of a muscle characterized by pain, tenderness and sometimes spasm.
  
  
• Herniated discs and degenerative disc disease.