Partial or complete loss of the ability to hear.
Inability or impaired ability to hear and interpret sounds, the two general types of ear and hearing problems being conductive losses and sensorineural losses.
Partial or total loss of the ability to perceive and identify sound. There are four general categories of hearing loss: conductive hearing loss, sensorineural hearing loss, mixed hearing loss, and central hearing loss. Each hearing loss can be distinguished from the other by the evaluation of hearing test results.
A decreased ability to perceive sounds as compared with what the individual or examiner would regard as normal. In the U.S., about 1 million school-age children and 25 million adults have some degree of hearing loss.