Hearing loss is one of the most common conditions affecting older adults. People with hearing loss may find it difficult to have a conversation with friends and family. They may also have trouble understanding a doctor’s advice, responding to warnings, and hearing doorbells and alarms. Hearing loss or hearing impairment happens when there is a problem with one or more parts of the ear or ears. Someone who has hearing loss or impairment may be able to hear some sounds or nothing at all. Impairment means something is not working correctly or as well as it should. People also may use the words deaf, deafness, or hard of hearing when they’re talking about hearing loss.
Hearing loss comes in many forms. It can range from a mild loss in which a person misses certain high-pitched sounds, such as the voices of women and children, to a total loss of hearing. It can be hereditary or it can result from disease, trauma, certain medications, or long-term exposure to loud noises.
Hearing loss can be categorized by which part of the auditory system is damaged. There are basically three basic types of hearing loss. These can be categorised into:
- Conductive hearing loss: Conductive hearing loss occurs when sound waves cannot reach the inner ear. The cause may be earwax build-up, fluid, or a punctured eardrum. Medical or surgical treatment can usually restore conductive hearing loss.
- Sensorineural hearing loss: Sensorineural hearing loss occurs when there is damage to the inner ear or the auditory nerve. This type of hearing loss is permanent.
- Mixed hearing loss: Sometimes a conductive hearing loss occurs in combination with a sensorineural hearing loss (SNHL). In other words, there may be damage in the outer or middle ear and in the inner ear (cochlea) or auditory nerve. When this occurs, the hearing loss is referred to as a mixed hearing loss.
About 3 in 1,000 babies are born with hearing impairment, making it the most common birth defect. A hearing problem can also develop later in life. To understand how and why hearing loss happens, it helps to know how the ear works.
- The outer ear,
- The inner ear.
- The middle ear, and
These parts work together so you can hear and process sounds. The outer ear, also known as the “Pinna” (the part you can see or the outer ear), picks up sound waves and the sound waves then travel through the outer ear canal. When the sound waves hit and reaches the eardrum in the middle ear, the eardrum starts to vibrate.
When the eardrum vibrates, it moves three tiny bones in your ear. These bones are called the hammer (or malleus), anvil (or incus) and stirrup (or stapes). They help sound move along on its journey into the inner ear. The vibrations then travel to the cochlea, which is filled with liquid and lined with cells that have thousands of tiny hairs on their surfaces. There are two types of hair cells: the outer and inner cells. The sound vibrations make the tiny hairs move. The outer hair cells take the sound information, amplify it (make it louder), and tune it. The inner hair cells send the sound information to your hearing nerve, which then sends it to your brain, allowing you to hear.