Diagnostics and testing
Diagnostic tests offered by WNY Rehabilitation Medicine and Pain Management
Dr. Zhan is an expert in the interpretation of electrodiagnostic studies including electromyography, nerve conduction studies, and evoked potentials. She is also trained in the interpretation of more sophisticated diagnostic studies that evaluate a patient’s musculoskeletal and neuromuscular systems such as CT and myelography.
The doctor and her team can carry out a range of tests, including Electrodiagnostic EMG/NCV studies and testing for diagnosis of carpal tunnel syndrome, ulnar neuropathy, cervical radiculopathy, lumbosacral radiculopathy, peripheral neuropathy and others.
EMG, or Electromyography testing
What is EMG?
EMG, or Electromyography is a technique for evaluating and recording the electrical activity produced by muscles. EMG is performed using a machine called the electromyograph, to produce a record called an electromyogram. An electromyogram detects the tiny amount of electricity generated by muscle cells when they are activated by the nerves connected to them. The signals are then analyzed to detect medical abnormalities in the spinal cord, nerves and the muscles that are connected to specific nerves.
There are two types of EMG: intramuscular EMG and surface EMG. The intramuscular EMG is the most common. It involves inserting a needle electrode through the skin into the muscle that is being studied. Surface EMG (SEMG) involves placing electrodes on the skin over the muscle to detect the electrical activity of the muscle. It is not used as often because it provides less useful information than the intramuscular EMG. These are evaluated by a physician who specializes in physical medicine or neurology and is trained to interpret the findings.
What are the uses of EMG?
EMGs can detect abnormal muscle electrical activity in many diseases and conditions, including inflammation of muscles, pinched nerves, damage to nerves in the arms and legs, disc herniation, and degenerative diseases such as muscular dystrophy, Lou Gehrig's disease and Myesthenia gravis, among others. The EMG helps doctors distinguish between muscle conditions that begin in the muscle and nerve disorders that cause muscle weakness.
What is NVC testing?
NCV, or Nerve Conduction Velocity, is an electrical diagnostic test that provides information about abnormal conditions in the nerves. Nerves are stimulated with small electrical impulses by one electrode while other electrodes detect the electrical impulse "downstream" from the first electrode. The resulting nerve impulses are then measured and the outcome is interpreted by the physician. The NCV test is often done at the same time as the EMG in order to exclude or detect both nerve and muscle conditions.
What are the uses of NCV?
While interpreting NCV, the distance between electrodes and the time it takes for electrical impulses to travel between electrodes are used to calculate the speed of impulse transmission. Slower than normal speed could indicate nerve damage from direct trauma, diabetic or peripheral neuropathy, viral nerve infection or nerve entrapment diseases like Carpal Tunnel Syndrome among other conditions.