Nerve Conduction Test

What is a Nerve Conduction Test?

Nerve conduction studies (NCS) and electromyography (EMG) are tests (Nerve Conduction Test) of the peripheral nervous system and muscular systems. These tests allow for the neurologist to evaluate whether a patient’s peripheral nervous system and muscles are functioning properly, and more specifically, allows the neurologist to localise nerve and muscle dysfunction accurately and with precision.

When the peripheral nervous system is injured and/or there is muscular dysfunction, patients tend to experience symptoms such as;

  • Pain
  • Numbness, tingling, pins and needles
  • Weakness

Nerve conduction studies and EMG testing helps us to localise the site of nerve injury, as well as quantify its severity and treat it in an appropriate way.

Nerve Conduction Test

Nerve Conduction Studies

Nerve conduction studies and EMG testing helps us to localise the site of nerve injury, as well as quantify its severity and treat it in an appropriate way.

The nerve conduction study uses electrical stimulus to activate a peripheral nerve and determine how fast/healthy it is. Nerve conduction studies record nerve responses from the surface of the skin using multiple electrodes and a stimulator probe. The test measures how well the nerve conducts along its length (nerve conduction-velocity) and compares the recorded response to known healthy responses. Peripheral nerves can become slow, damaged or abnormal in a variety of ways and including problems such as;

Carpal Tunnel Syndrome

Ulnar Neuropathy

Brachial and Lumbosacral Plexopathy

Peripheral Neuropathy (including axonal, demyelinating and mixed-type neuropathies)

Hereditary Sensorimotor Polyneuropathy

Neuromuscular disorders such as myasthenia gravis

Cervical and lumbosacral radiculopathy

The nerve conduction test study helps us to differentiate nerve problems more accurately, and when complemented with electromyography (EMG), helps us to examine muscle function as well.

Electromyography

Electromyography (EMG) testing involves the use of small electrode needles placed into the muscle of the patient, which allows for recording of a muscle’s electrical activity. In the event of neuromuscular injury, the electrical activity recorded from affected muscles will be different when compared to a healthy muscle. This allows for precision when trying to identify the specific location/level of the neuromuscular injury.

In the event of severe peripheral nerve injury, for example, sometimes muscles can become weaker than their healthy counterparts; EMG helps to evaluate the severity of muscle denervation (where the nerve no longer gives power to its respective muscles) and determine whether there is ongoing nerve dysfunction (acute) or the injury is chronic in nature. This allows for rapid, tailored treatment decisions in the event of ongoing nerve and muscle injuries (acute denervation), versus more conservative treatment plans for patients with chronic injuries (chronic denervation).

Nerve Conduction Test at Neuro NSW

The team at NeuroNSW also provides quantitative analysis of EMG results for more accurate information from neuromuscular testing. This quantitative EMG complements conventional diagnostic techniques like CT and MRI scanning, allowing for accurate quantification of nerve dysfunction when seen on imaging, calculated as a percentage of observed nerve or muscle dysfunction seen during the EMG testing.

Both the nerve conduction study and EMG test are diagnostic tools which aid the Neurologist in reaching a definitive diagnosis in relation to a patient’s symptoms or complaints, which then allows for appropriate treatments. Both NCS and EMG testing can be performed multiple times over the course of investigation or treatment, and allows for real-time evaluation of a patient peripheral nervous system.

NeuroNSW’s Nerve Conduction Studies and EMG are usually performed together, with testing usually taking 1 hour and sometimes longer for more complex tests/examination.