Electromyography, or EMG, involves the assessment of the electrical activity of muscles. This examination is often accompanied by another test, nerve conduction studies (NCS), which evaluate the conduction velocities of the nerves. The combination of both tests, which are frequently performed simultaneously, using the same medical device, in the same setting, and by the same specialist, is referred to as a full neurophysiological evaluation.
Muscle movement involves the function of both muscles and nerves and requires the presence of electric current at the cellular level. This current is significantly weaker than household electrical current. In certain medical conditions, this electrical activity in muscles and nerves can be affected. Recording and identifying these electrical properties may help physicians diagnose such conditions.
Electromyography can assist in diagnosing conditions caused by nerve entrapment or injury (such as carpal tunnel syndrome or radiculopathy), as well as other disorders of the muscular and nervous systems. Less common diagnostic uses include the evaluation of conditions such as Amyotrophic Lateral Sclerosis (ALS), Myasthenia Gravis, and muscular dystrophy.
