[3][4][5][1] Nerve conduction studies are also used for evaluation of paresthesias (numbness, tingling, burning) and/or weakness of the arms and legs.

[6] Patients typically do not require special preparation before undergoing an NCS and should take their medications and eat normally prior to the examination.

[6] Patient should be advised to avoid applying lotions or creams to the skin, as these substances can interfere with electrode conductivity.

The Department of Health and Human Services Inspector General recently identified the use of NCSs without a needle electromyography at the same time a sign of questionable billing.

[9] The nerve conduction study consists of the following components: Below is a general list of equipment used during an NCS, but it may not include everything an NCA practitioner may use.

The interpretation of nerve conduction studies is complex and requires the expertise of health care practitioners such as clinical neurophysiologists, medical neurologists, physical therapists, or physiatrists.

[6][7][8] NCS results provide information on whether a nerve conducts electrical signals at a normal speed and strength.

This method of calculating conduction velocity avoids being confounded by time spent traversing the neuromuscular junction and triggering a muscle action potential (since these are subtracted out).

Conduction velocity is derived by measuring the limb length, D, in millimeters from the stimulation site to the corresponding spinal segment (C7 spinous process to wrist crease for median nerve).

An h-reflex study uses stimulation of a nerve and recording the electrical reflex discharge from a muscle in the limb.

[12] However, there exists the "theoretical concern that electrical impulses of nerve conduction studies " could be pick up by sensory mechanism with the devices.

[12] The American Association of Neuromuscular & Electrodiagnostic Medicine has stated that despite these concerns, "no immediate or delayed adverse effects have been reported with routine NCS.

Due to the typical lead placement of deep brain stimulators from the "subclavicular area to the lateral posterior neck" and then to the "occipital area", there is a "theoretical risk of introducing electrical current through the leads" which could transmit "directly into the brain" and through the cervical nerve roots.

[12] The American Association of Neuromuscular & Electrodiagnostic Medicine has stated that there are "no known contraindications" that "exist from performing needle EMG or NCS on pregnant patients.