270.393.8418

Reliable neurological testing in a comfortable environment

Slide background Electromyography — EMG

WHAT IS EMG?

EMG is a diagnostic procedure to assess the health of muscles and nerve cells that control the muscle (motor neurons).

 

HOW DOES EMG WORK?

Since motor neurons transmit electrical signals that cause the muscles to contract, the EMG utilizes electrodes to translate these signals into graphs, sounds and numerical values to be interpreted by skilled specialists.

Another aspect of EMG involves needle electrodes, where a needle is inserted into a given muscle to record activity. Normal, healthy muscle function should not produce activity when the muscle is at rest. From there, we record the spikes in electrical currents that occur during voluntary contractions and nerve stimulation, subsequently interpreting and reporting our findings to the patient.

There is also an aspect of EMG called a Nerve Conduction Study that uses electrodes taped to the skin (surface electrodes) to measure the speed and strength of the electrical signals.

 

WHAT WILL I LEARN FROM AN EMG?

EMG testing can reveal muscle dysfunction, nerve dysfunction or a breakdown in communication between the nerves and muscles. Your doctor may order an EMG if you are experiencing any of the following symptoms, which may indicate a nerve or muscle disorder.

 

SYMPTOMS

  • Tingling
  • Numbness
  • Muscle Weakness
  • Muscle Pain or Cramping
  • Certain types of Limb Pain

 

EMGS CAN HELP DIAGNOSE OR RULE OUT

  • Muscle Disorders: Muscular Dystrophy, Polymyositis
  • Diseases affecting the connection between nerve and muscle: Myasthenia Gravis
  • Peripheral Nerve Disorders: Carpal Tunnel Syndrome and Peripheral Neuropathies
  • Disorders that affect the motor neurons in the brain or spinal cord: Amyotrophic Lateral Sclerosis, Polio
  • Disorders that affect the nerve root: Herniated Disk in the Spine
  • Ataxias
  • Chronic Pain
  • Congenital Myopathies
  • Fibromyalgia
  • Guillain-Barré Syndrome
  • Metabolic Myopathies
  • Mitochondrial Myopathies
  • Myotonias
  • Nerve Lesions
  • Radiculopathies
  • Spinal Muscular Atrophy

 

CAUTION

Be sure to alert your Neurologist and the EMG technician if

  • You have a pacemaker or other electrical medical device
  • Have hemophilia
  • Take blood thinners

 

PREPARATION

Take a bath or shower before your EMG appointment to remove oils from the skin, and avoid fragrances or lotions.

 

WHAT YOU CAN EXPECT

The EMG test can take up to 2 hours. Both the technician and neurologist are present in the room. The technician adheres surface electrodes to various places on your skin, while the neurologist inserts needle electrodes at different locations.

The electrodes emit a small electrical current that feels much like a twinge or spasm. Some discomfort may occur until the needle is removed. During the needle EMG, the neurologist will ascertain the amount of activity at different stages as you rest or contract the muscle, or change positions.

 

AFTER THE EMG

The risks of EMG testing is minimal. You may experience temporary minor bruising or tenderness. There is a slight chance of bleeding, infection, or nerve injury at the insertion site of the needle, but complications are rare. Be sure to contact your primary care doctor if side effects persist.