EMG is a diagnostic procedure to assess the health of muscles and the nerve cells that control them.
Motor neurons transmit electrical signals that cause muscles to contract. An EMG translates these signals into graphs, sounds or numerical values that a Neurophysiologist interprets.
The referring doctor may order for the tests if you have signs or symptoms that may indicate a nerve or muscle disorder. Such symptoms may include:
These two studies go hand in hand and are required to differentiate Nerve from Muscle diseases.
It evaluates the site and severity of the nerve lesion and further differentiating into Demyelinating vs Axonal Neuropathy.
Hence helping the referring doctor to further evaluate and decide for the line of treatment.
Some sticky pads will be placed on parts of your limbs, these are to record the responses from your nerves and tell us how well they are working.
To make your nerves work we need to stimulate them. This is done either with some clips on your finger or with a special probe. The shocks given are in Milli amperes and are quite bearable. The stimulus is local and does not travel all over the body. The Motor conduction stimulus feels like a tap and causes movement of the area being stimulated.
These are specialized tests which involve three major tests that measure responses to Visual, Auditory and Electrical stimuli
VEP : Visual evoked Potentials
This method currently provides the most sensitive means of detecting lesions of the Optic nerves.
BAEP : Brainstem Auditory Evoked Potentials
BERA : Brainstem Electric Response Audiometry
A somatosensory evoked potential (SSEP) is an evoked potential caused by an electrical stimulus. This investigation therefore tests the pathway of the sensory nerves to the sensory areas of the brain.
A doctor may recommend you go for a SSEP test if you have been experiencing feelings of numbness or weakness in your arms or legs that may be due to problems affecting the spinal cord functioning
The SSEP procedure itself is safe and non-invasive.