What is deafness and hearing loss?

Deafness or hearing loss is the inability to hear the surrounding noise. It can be partial or total impairment,  unilateral or bilateral.

When people cannot hear, they will ask to repeat the words. This can be a symptom or a starting stage of hearing loss.

When a person has hearing loss, they will hear muffled television or radio sounds. They might tend to turn the volume up as they cannot hear the words properly.

Many reasons can lead to hearing loss, including ageing, long-term exposure to loud sounds, trauma  and certain diseases  like CSOM, otosclerosis etc,   and  medications.  Heredity can also play a crucial role in hearing loss and deafness. Due to certain genetic factors, hearing loss can run through families Deafness can also be present at birth- inborn deficiency

All Deafness cannot be cured ,where it cannot be cured  a hearing aid might help them hear the surrounding noise without difficulty.

Some people with Profound  hearing  loss,   with the help of lip movement, find out what the other person is talking about. But this technique is not reliable. Another method of communication will be sign language.

The parts of the ear include the inner ear, middle ear and outer or external ear.

The parts of the external ear include the pinna or auricle and the tube or external auditory canal. The pinna forms the outer part of the ear. The external auditory canal is a long tube that connects the outer ear to the inner and middle ear.

The middle ear, also called the tympanic cavity, consists of ossicles and three small bones— malleus, incus and stapes. The ossicles, with the help of small bones, are responsible for transmitting sound waves to the inner ear.

The inner ear consists of the vestibule, cochlea and semi-circular canals. The cochlea consists of the nerves that are responsible for hearing sounds. The vestibule and semi-circular canals contain balance receptors.

Deafness-related problems, symptoms, diagnosis and treatment are briefed in this blog below.

How do we hear?

The process of hearing starts from the outer ear. The outer ear captures the sound waves or vibrations. These sound waves travel down the external auditory canal and strike the eardrum.

The sound waves make the eardrum vibrate. These vibrations pass to the middle ear, and the ossicles amplify the sound.  

These vibrations are then passed to the inner ear and cochlea. The inner ear converts the sound waves or the vibrations into electrical signals.

The auditory nerves capture the electrical signals and send these impulses to the brain. The brain translates the impulses as sound. These set of actions and reactions takes place in a fraction of a second.

Types of deafness and hearing loss

Hearing loss can arise at any age and can be caused due to various reasons. The intensity of deafness can vary.

There are  three types of hearing loss.  

Conductive hearing loss

Conductive hearing loss develops when the sound waves cannot pass through the middle and outer layers of the ear.

This type of hearing loss happens when the sound is blocked by excessive earwax deposition or by the placement of foreign objects. Other factors like injury  to the ear drum  resulting in perforation, eardrum fluid impaction, Infections like CSOM,  and bone abnormality may also be a factor for deafness.

Conductive hearing loss can be cured with surgical and medical treatment. In most cases, surgery will not be required.

Conductive hearing loss is common in children as they are prone to ear infections, and children often insert foreign objects into their ears. These objects may damage the ear canal and lead to hearing loss.  

Sensorineural hearing loss

When the inner ear is damaged, it is called sensorineural hearing loss.
The inner ear contains many small and minute structures that help to hear. These include ear hairs. These hairs help to pass the vibrations or sound waves. Damage to the inner ear hairs can impair hearing. When the nerve is damaged in the inner ear, or the nerve that carries sound waves to the brain is damaged, it  results in  sensorineural hearing loss.

In this type of hearing loss, soft sounds will not be heard or will be difficult to hear. Loud sounds will be muffled or   words  will not be clear .

Medicine or surgery cannot fix  sensorineural hearing loss, but a hearing aid can help with the hearing loss.

Sensorineural hearing loss can be brought on by severe illnesses like meningitis, jaundice and mumps, chicken pox and other viral infections. Other causes like repeated and prolonged  exposure to loud noise, ageing, hereditary deafness, drugs that can affect the ear nerves and injury to the head.

The symptoms of sensorineural hearing loss include discomfort or muffled hearing of background noise, ringing in the ears (tinnitus) and difficulty understanding  words.

People will have difficulty hearing consonants. When people speak, there will be a mixture of high and low-frequency words.   

Vowels like “a”, “e”, “i”, “o” and “u” have low frequency and can be heard easily, whereas consonants like “s”, “h” and “b” have high frequency, so it will be difficult to hear.

Mixed hearing loss

There is a possibility of your inner and outer ear getting damaged at the same time. This damage can make hearing very difficult and lead to mixed hearing loss.

Mixed hearing loss can cause damage to the inner, middle or outer layer or the nerve that carries the sound waves to the brain.

 Mixed hearing loss can cause mild to severe hearing loss.

The causes of mixed hearing loss include genetic reasons, head injury, trauma, drugs, major illness, ear infection, excessive fluid secretion long-term exposure  to loud noises and malformation and function of the middle or inner ear.

Sensorineural hearing loss can be corrected with hearing aids, and conductive hearing loss can be rectified with surgery or treatments. A patient might require a combination of medical treatment and surgery if affected with mixed hearing loss.  

In some cases, they might need hearing aids along with surgery. In other cases, only implants or special hearing aids will be needed.

Diagnosis of deafness or hearing loss can be made by simple tests.  

Physical examination

Your doctor will conduct a simple physical examination. The doctor will examine your ears for the presence of any foreign objects or wax. Hearing loss can also happen due to severe ear infections. A simple test will be conducted with a tuning fork.

Required tests- Puretone audiometry  & Impedence audiometry will show the type of hearing loss and also some the conditions like fluid in the middle ear and ossicular defect.  MRI is done to rule out tumors in the brain.     , 

Congenital hearing loss  

This may be due to genetic causes, complications during birth, a maternal infection that can affect the baby and head trauma.

 Can be due to malformation or absence of sound conducting mechanism in the outer & Middle ear   or malformation in the inner ear.

Surgery can  be done  to correct the defects in the outer and middle ear & restore hearing.
For inner ear malformation   surgery by cochlear implant is an option.

In the absence of inner ear malformation –  Sign language and lip-reading is used.Sign language uses hand signals, facial expressions, gestures and body language to communicate with people.  Lip reading is the technique of understanding what a person speaks by interpreting the movement of lips. This can help, but at times lip reading can be misinterpreted.

Prenatal screening    

Fetal motion in response to sound and auditory evoked potential testing can determine the presence of fetal hearing in the third trimester of pregnancy. Imaging modalities including ultrasound, computed tomography, and magnetic resonance imaging hold promise for the diagnosis of some forms of congenital deafness in the second trimester.

New born hearing screening 

Newborn hearing screening by one month of age, ideally before they go home from the hospital  so that they can receive early intervention services  There are two different methods to test hearing loss in infants, and they are the automated auditory brainstem response (AABR) evaluations and the automated otoacoustic emission (AOAE) measures.

Symptoms

Withdrawal from conversations

Hearing loss can affect a person psychologically. A person with hearing impairment might tend to move away from the conversation. They might have difficulty communicating with others.

Avoidance of some social settings

Because of the hearing impairment, they might move away from the social setting and conversation.

Risk factor

Ageing 

Ageing is a common factor of hearing loss. As a person ages, the body tissues may start degenerating, and the same occurs to the ear nerves. As a result, aged people may have hearing loss.

Loud noise

Hearing loss can happen when people are exposed to loud noise continuously for a long period of time. A sudden loud noise can damage the eardrums and can cause hearing loss.

Heredity

Heredity can also play a crucial role in hearing loss and deafness. Due to certain genetic factors, hearing loss can run through families.

Occupational noises

People working in a loud environment are more prone to hearing loss. They continuously get exposed to such long noise, and their eardrums can be damaged.

Recreational noise

Exposure to explosives can cause permanent damage to the ears that lead to hearing loss.

Some medications

Sometimes medication  like aspirin and antibiotics  like gentamycincan cause hearing loss.

Some illnesses 

Significant illness and infection to the ear can cause hearing loss.

Conclusion

The ear contains minute nerves and a small organ inside the ear that is very delicate. Hearing loss in old age can be very common. But when you have sudden hearing loss, you should immediately consult the doctor. Long-term exposure to loud noise can lead to permanent hearing loss.

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