Clinical neurophysiology is the study of nervous system disorders. A neurophysiologist is a neurologist or psychiatrist who specializes in the diagnosis and management of nervous system disorders using a combination of clinical evaluation and technical device testing, such as electroencephalography (EEG) or electromyography (EMG). These test results are interpreted by the neurophysiologist and communicated to the patient to treat nervous system disorders, such as carpal tunnel syndrome or a ruptured disc in the spine causing sciatica.