Nerve Conduction Studies (NCS)

Due to their premier medical facilities, the neurology department at Aster Hospitals offers one of the best treatment and diagnostic facilities for several types of neurological disorders. Aster Hospitals is well-equipped with highly skilled doctors and the latest medical tools, required for the diagnosis and treatment of neurological diseases.

Neurological diseases with or without systemic involvement can cause discrepancies in nerve conduction. In such cases, the nerve conduction test is a primary diagnostic tool. Also called a nerve conduction study, this test measures how fast impulses can be conducted through your nerves. This test helps to diagnose nerve damage.

During a nerve conduction study

During a nerve conduction test, two electrode patches are stuck onto your skin overlying a nerve, with two electrodes attached to a machine. One electrode gives the nerve a minor electrical impulse while the other measures it. The process is repeated on all the different parts of the body where nerve damage is suspected.

The nerve impulse speed is deduced based on the distance between the electrodes and the time taken to receive a response on the electrode. 

A combination test called the EMG or electromyography is sometimes  done along with the NCS. This test checks for the electric responses between nerves and muscle tissue. Both these tests help to diagnose, locate and check for the extent of nerve and muscle damage in the tissue area.

Indications for a nerve conduction study

A nerve conduction study may be indicated in the following conditions:

Guillain barre syndrome

This syndrome involves a problem with the immunity system of the patient, wherein it tends to attack the peripheral nervous system.

Symptoms:

• Loss of sensation in legs
• Tingling sensation in limbs
• Loss of power in legs
• Breathing difficulty 

Carpal tunnel syndrome

This happens when the median nerve, which passes along the forearm from the elbow to the wrist, is compressed or twisted due to surrounding pressure or an enlarged muscle. This is a common occurrence during fluid accumulation in pregnancy.

Symptoms

• Tingling or numbness in the hand and fingers.

Charcot Marie tooth disease

This disease is an inherited disorder that hampers both the motor and sensory nerves.

Symptoms

• Weakness in the foot
• Sensing difficulties in the legs
• Foot deformities 

Intervertebral disc herniation

This happens when the fibrous cartilaginous disc between the vertebrae gets flattened out or faces outwards (the gelatinous membrane breaks down), causing compression on the spinal cord.

Symptoms

• Pain in limbs
• Numbness in the affected vertebral region
• Law back ache
• Weakness of the limbs

Chronic inflammatory polyneuropathy

This neurological problem is associated with uncontrolled diabetes or severe alcohol consumption. 

Symptoms

• Tingling and numbness in one or several parts of the body

Sciatic nerve issues

The most common cause of sciatic nerve damage  is a bulging or malformed Intervertebral disc that puts pressure against the roots of the nerve, leading to sciatic nerve pain.

Symptoms

• Pain
• Numbness
• Weakness

A lot of times, nerve conduction studies and electromyography can be advised to detect the cause of continuous pain or chronic numbness in any part of the body due to unknown reasons.

Steps before an NCS

• Your neurophysician / neruo technician will explain the procedure to you and your family in detail, and you can ask any related questions.
• You/your guardian will be asked to sign a consent form that permits you to do the test. Make it a point to read the form carefully, and ask questions when instructions are unclear.
• In most cases, fasting or sedation is not a prerequisite before the procedure.
• Care should be taken to maintain an average body temperature before taking this test, as a fluctuating body temperature can interfere with the readings and interpretation.
• Inform your physician about all the medicines (prescription and over-the-counter) or herbal supplements you take.
• Dress in comfortable clothes that are modest and allow easy access to the area to be tested, or clothes that can be easily removed.
• Avoid using lotions/oils on your skin for a few days before taking the NCS or EMG test.
• Depending on your general health condition, your physician may/may not ask you a few other things to be done before taking the test. 

During an NCS

An NCS or EMG is a mildly uncomfortable procedure. Still, your doctor will try to make it as comfortable as possible. A typical NCS or EMG requires 20 minutes to an hour to be completed depending upon the extent of the area to be tested. 

• It is an outpatient procedure, or it can be one of the tests done during hospitalization. A specialist doctor, such as a neurophysician, or an interventional medical technician will be responsible for conducting the test.
• Remove all jewelry before the test, including hearing aids, hairpins, etc.
• Obstructive clothing will be changed to a comfortable gown.
• The patient will be made to lie down in most cases.
• The neurophysician will check and demarcate areas to be tested.
• Electrode tapes will be attached to the body using a cool lotion. The other end will be attached to the machine and kept at a distance.
• A small, mild current will pass through your body, which may/may not give a response on the machine and can be a little uncomfortable.
• The reading will be displayed on the machine monitor.

After an NCS

The NCV is a relatively easy diagnostic test for nerve conduction or nerve damage. It is not invasive, and the patient can return to their daily schedule once the test is completed with further discussions with/instructions from their doctor.

Precautions/risks of NCV TEST

• Inform your physician if you have any electrical medical devices in your body, like a pacemaker.
• Discuss in detail the risks involved in doing the test and whether your condition allows you to be an ideal candidate.