Electromyography/Nerve Conduction Velocities (EMG/NCV's) These are among the most important tests to study pinched nerves, diseases affecting the nerves in the limbs, and muscle diseases; problems which may produce numbness, tingling, pain and weakness in the limbs. During NCV's, mild electrical stimulation is applied to nerves over the limbs and their impulses recorded. During EMG, a single, small, Teflon-coated, needle-shaped electrode is placed in the muscles just under the skin and the muscles' own electrical activity is recorded. The patient may experience mild transient discomfort during the procedure. A patient should not use lotions or oils on the skin on the day of the test, otherwise no preparation is necessary and the patient can drive home immediately afterward.