In general terms, audiologists are hearing doctors who specialize in hearing loss and who are trained to conduct hearing exams. Audiologists have extensive knowledge of the human auditory and vestibular systems, and they are trained in sound reproduction. Hearing instrument specialists must pass a written exam in order to receive a license to practice in the region where they work. They are trained to interpret hearing tests, program hearing devices, and advise on hearing care solutions. In contrast to an audiologist, these specialists do not require a master’s or doctorate degree to practice. ENT (ear, nose, & throat) doctors (or otolaryngologists) are ear doctors who are medical doctors and have a doctorate degree in medicine. They are trained to perform ear surgery and handle more profound hearing loss conditions. They can also treat ear infections and ear trauma.