Tests that are used to diagnose diseases of the nerves and muscles. Electrodiagnostic studies record electrical activity in the body. They are used to evaluate symptoms such as numbness, tingling, pain, weakness, and muscle cramping. There are a number of possible electrodiagnostic tests, including electromyogram (EMG), evoked responses, nerve conduction studies, which show how the body’s electrical signals travel through the body’s nervous system, and electroencephalogram (EEG).