Although the term “deaf” is often mistakenly used to refer to all individuals with hearing difficulties, the word deaf usually refers to an individual with very little or no functional hearing and who often uses sign language to communicate. Hard of Hearing refers to an individual who has a mild-to-moderate hearing loss who may communicate through sign language, spoken language, or both. Hearing Impaired, used to describe an individual with any degree of hearing loss, is a term offensive to many deaf and hard-of-hearing individuals. They consider the terms "deaf" and "hard of hearing" to be more positive. Although it is true that their hearing is not perfect, they prefer not to be labeled "impaired" as people.
A hearing loss can be caused by many physical conditions (e.g., childhood illnesses, pregnancy-related illnesses, injury, heredity, age, excessive or prolonged exposure to noise), and result in varying degrees of loss. Generally, hearing loss is categorized as mild, moderate, severe, or profound. An individual with a moderate hearing loss may be able to hear sound, but have difficulty distinguishing specific speech patterns in a conversation. Individuals with a profound hearing loss may not be able to hear sounds at all. Both people who are deaf and those who are hard of hearing can be individuals with disabilities within the meaning of the American Disabilities Act (see below).
The many different circumstances under which individuals develop hearing loss can affect the way they experience sound, communicate with others, and view their hearing loss. For example, some individuals may use American Sign Language (ASL) and others may rely on lip reading and voice.
The Americans with Disabilities Act (ADA)
The Americans with Disabilities Act (ADA) is the federal law that prohibits discrimination against individuals with disabilities. Title I of the ADA covers employment by private employers with 15 or more employees and state and local government employers of the same size. Section 501 of the Rehabilitation Act provides the same protections for federal employees and applicants for federal employment. Most states also have their own laws prohibiting employment discrimination on the basis of disability. Some of these state laws may apply to smaller employers and provide protections in addition to those available under the American Disabilities Act. The U.S. Equal Employment Opportunity Commission (EEOC) enforces the employment provisions of the ADA.
A hearing impairment is a disability under the ADA if: (1) it substantially limits a major life activity; (2) it substantially limited a major life activity in the past; or (3) the employer regarded (or treated) the individual as if his or her hearing impairment was substantially limiting. The determination of whether a hearing impairment is substantially limiting is made on an individualized, case-by-case basis.
Source: Questions and Answers about Deafness and Hearing Impairments in the Workplace and the Americans with Disabilities Act, http://www.eeoc.gov/facts/deafness.html#fn8