In addition to nerve conduction studies, the neurophysiologist may also perform electromyography (EMG) which will give useful information regarding the healthiness or otherwise of the muscle nerve supply and of the muscle itself. This technique involves inserting a thin needle into various muscles and recording the electrical activity of the muscle both at rest and during muscle activity. The needle used is very thin and normally only causes minor discomfort. There may be some soreness or bruising for a short while afterwards. If you are taking blood thinning medication such as warfarin this should not prevent this test being done but the specialist may limit the number of muscles so tested so please let him or her know if you are taking such medication.