A hearing disorder is the result of impaired auditory sensitivity of the physiological auditory system. A hearing disorder may limit the development, comprehension, production, and/or maintenance of speech and/or language. Hearing disorders are classified according to difficulties in detection, recognition, discrimination, comprehension, and perception of auditory information. Individuals with hearing impairment may be described as deaf or hard of hearing.

• Deaf is defined as a hearing disorder that limits an individual’s aural/oral communication performance to the extent that the primary sensory input for communication may be other than the auditory channel.
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• Hard of hearing is defined as a hearing disorder, whether fluctuating or permanent, which adversely affects an individual’s ability to communicate. The hard-of-hearing individual relies on the auditory channel as the primary sensory input for communication.