Electromyography involves testing the electrical activity in the nervous system. Often, EMG testing is performed with another test that measures the conducting function of nerves. This is called a nerve conduction study. EMG may aid with the diagnosis of nerve compression or injury (such as Carpal Tunnel Syndrome), nerve root injury (such as Sciatica), and with other problems of the muscles or nerves. Less common medical conditions include Amyotrophic Lateral Sclerosis (ALS), myasthenia gravis, and muscular dystrophy. Electromyogram (EMG) and Nerve Conduction Studies