Hearing impairment, deafness, or hearing loss refers to the total or partial inability to hear sounds.
Symptoms may be mild, moderate, severe, or profound. A patient with a mild hearing impairment may have problems understanding speech, especially if there is a lot of noise around, while those with moderate deafness may need a hearing aid.
Some people are severely deaf and rely on lip-reading to communicate with others. People who are profoundly deaf can hear nothing at all and can find themselves totally reliant on lip-reading or sign language.