A nerve conduction study (NCS) is an electrodiagnostic test used to evaluate the electrical conduction, and thus the function of the motor and sensory nerves of the body.
Uses of sensory NCS include evaluating parasthesias (numbness, tingling burning sensations) in a limb or a part of the limb (eg. Carpal tunnel syndrome, Guyon's canal syndrome, peroneal neuropathy), in two or more limbs or parts of the limbs (eg. Guillain-Barré syndrome, diabetic neuropathy)
Uses of motor NCS include evaluating weakness in muscle/s of limb/s (eg. nerve root compression due to herniated disc, motor neuron disease, muscular dystrophy, poliomyelitis)
NCS is indicated when there is:
Electromyography (EMG) is an electrodiagnostic technique used for recording the electrical activity produced by skeletal muscles. An electromyograph is used to detect the electrical potentials generated by muscle cells when they are neurologically or electrically activated. These signals are then analyzed to evaluate normal or abnormal activation level and recruitment of muscle fibers in various disorders of muscles and nerves of central nervous system as well as peripheral nervous system.