The Cochlear Implant School Toolkit

1 - How Hearing Works

What is hearing loss?

Hearing loss refers to the inability to perceive or interpret sounds. Hearing loss is clinically categorized as mild, moderate, severe, or profound depending on the degree of loss.

Generally, being deaf is when hearing loss is severe enough to prevent a person from using their hearing to process information.
Hearing loss can be caused by genetic abnormalities, illness, certain medications, and medical syndromes, but many causes of hearing loss are unknown.

Approximately 90 percent of deaf children are born to hearing parents.