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.
Hearing loss vs. deafness
It is important to distinguish between the different levels of hearing loss.
Hearing loss: This is a reduced ability to hear sounds in the same way as other people.
Deafness: This occurs when a person cannot understand speech through hearing, even when sound is amplified.
Profound deafness: This refers to a total lack of hearing. An individual with profound deafness is unable to detect sound at all.
The severity of hearing impairment is categorized by how much louder volumes need to be set at before they can detect a sound. Some people define profoundly deaf and totally deaf in the same way, while others say that a diagnosis of profound deafness is the end of the hearing spectrum.
Types
There are three different types of hearing loss:
1) Conductive hearing loss
This means that the vibrations are not passing through from the outer ear to the inner ear, specifically the cochlea. This type can occur for many reasons, including:
- an excessive build-up of earwax
- glue ear
- an ear infection with inflammation and fluid buildup
- a perforated eardrum
- malfunction of the ossicles
- a defective eardrum
Ear infections can leave scar tissue, which might reduce eardrum function. The ossicles may become impaired as a result of infection, trauma, or fusing together in a condition known as ankylosis.
2) Sensorineural hearing loss
Hearing loss is caused by dysfunction of the inner ear, the cochlea, auditory nerve, or brain damage. This kind of hearing loss is normally due to damaged hair cells in the cochlea. As humans grow older, hair cells lose some of their function, and hearing deteriorates.
Long-term exposure to loud noises, especially high-frequency sounds, is another common reason for hair cell damage. Damaged hair cells cannot be replaced. Currently, research is looking into using stem cells to grow new hair cells. Sensorineural total deafness may occur as a result of congenital deformities, inner ear infections, or head trauma.
3) Mixed hearing loss
This is a combination of conductive and sensorineural hearing loss. Long-term ear infections can damage both the eardrum and the ossicles. Sometimes, surgical intervention may restore hearing, but it is not always effective.
Symptoms
The symptoms of hearing impairment depend on its cause. Some people are born without being able to hear, while others suddenly become deaf due to an accident or illness. For most people, symptoms of deafness progress gradually over time. Some conditions may have hearing loss as a symptom, such as tinnitus or stroke.
Hearing impairment in infants
The following signs may indicate a hearing problem:
- Before the age of 4 months, the baby does not turn their head toward a noise.
- By the age of 12 months, the baby still has not uttered a single word.
- The infant does not appear to be startled by a loud noise.
- The infant responds to you when they can see you, but respond far less or do not respond at all when you are out of sight and call out their name.
- The infant only seems to be aware of certain sounds.
Hearing impairment in toddlers and children
These signs might become more evident in slightly older children:
- The child is behind others the same age in oral communication.
- The child keeps saying “What?” or “Pardon?”
- The child talks in a very loud voice, and tends to produce louder-than-normal noises.
- When the child speaks, their utterances are not clear.
Treatment
Help is available for people with all types of hearing loss. Treatment depends on both the cause and severity of the deafness. Sensorineural hearing loss is incurable. When the hair cells in the cochlea are damaged, they cannot be repaired. However, various treatments and strategies can help improve quality of life.
Hearing aids
These are wearable devices that assist hearing.
There are several types of hearing aid. They come in a range of sizes, circuitries, and levels of power. Hearing aids do not cure deafness but amplify the sound that enters the ear so that the listener can hear more clearly.
Hearing aids consist of a battery, loudspeaker, amplifier, and microphone. Today, they are very small, discreet, and can fit inside the ear. Many modern versions can distinguish background noise from foreground sounds, such as speech.
A hearing aid is not suitable for a person with profound deafness.
The audiologist takes an impression of the ear to make sure the device fits well. It will be adjusted to suit auditory requirements.
Cochlear implants
If the eardrum and middle ear are functioning correctly, a person may benefit from a cochlear implant. This thin electrode is inserted into the cochlea. It stimulates electricity through a tiny microprocessor placed under the skin behind the ear.
A cochlear implant is inserted to help patients whose hearing impairment is caused by hair cell damage in the cochlea. The implants usually improve speech comprehension. The latest cochlear implants have new technology that helps patients enjoy music, understand speech better even with background noise, and use their processors while they are swimming.
