Hearing care professionals specialize in hearing aid fitting and technology. In most every state, they are licensed to both test hearing and to fit hearing instruments to address hearing loss. Audiologists have master’s degrees or higher in audiology. They perform non-medical evaluations of hearing losses, including advanced testing for purposes beyond fitting hearing aids. They also develop non-medical hearing rehabilitation programs. For example, they often create rehabilitation programs for children whose hearing impairment might otherwise cause problems in language development. Many audiologists also dispense hearing aids. When a medical problem is suspected, both hearing aid dispensers and audiologists refer their clients to physicians for diagnosis.