Brain physiology studies using rTMS, nerve conduction studies (electrical nerve stimulation) and EEG. A nerve at the subject's wrist is stimulated with electrical impulses to measure the speed with which nerves conduct electrical impulses and the strength of the connection between the nerve and the muscle. rTMS is performed for 20 minutes. The EEG measures the electrical activity of the brain (brain waves). For this test, electrodes (metal discs) are placed on the scalp with a conductive gel and the brain waves are recorded while the subject moves his or her thumb briskly for 20 minutes.