People who are deaf or hard of hearing use a variety of ways to communicate. Some rely on sign language interpreters or assistive listening devices; some rely primarily on written messages. Many can speak even though they cannot hear. The method of communication and the services or aids the hospital must provide will vary depending upon the abilities of the person who is deaf or hard of hearing and on the complexity and nature of the communications that are required. Effective communication is particularly critical in health care settings where miscommunication may lead to misdiagnosis and improper or delayed medical treatment.