Hearing loss/hearing impairment/hard of hearing are all terms used to describe partial or total inability to hear. It occurs when there is decreased sensitivity to sounds that are normally heard. In children, it could affect development of speech/language. Hearing
is classified into two types: conductive hearing loss, where there is a break in the conduction of sound waves along the route through the outer ear, eardrum, or middle ear; sensorineuronal hearing loss (SNHL), where the cause is a damage in the nerves, the inner ear, or the brain.
Causes of Hearing Loss
Hearing loss could be genetic or could be acquired from an occurrence of an illness. Other reasons include the use of ototoxic medications
that damage the ears, persistent exposure to loud noises, head trauma or the aging process in general. Adenoids at times continue to grow even after adolescence and may eventually obstruct the Eustachian tube leading to conductive hearing loss and nasal infections that could slowly spread to the middle ear.
Hearing Loss in Children:Otitis media:
This is the inflammation of the middle ear, which is caused by accumulation, or build-up of fluid that may or may not be infected. Children are generally prone to this, since their Eustachian tube is relatively small and blockage in ears may be caused by conditions such as large adenoids and infections.
When there is build-up of fluid inside the middle ear, sound vibrations are not transmitted efficiently to the inner ear, which could result in mild to moderate hearing loss. This is a temporary hearing loss, however if otitis media occurs frequently, it could lead to permanent sensorineural hearing loss. It could also lead to speech and language problems in children.
Impacted earwax, certain allergies or foreign body in the ear are common causes that affect hearing.Congenital hearing loss:
It could include hereditary hearing loss, or hearing loss due to other factors present at birth. Prenatal infections, maternal diabetes or toxemia during pregnancy may also cause congenital hearing loss.
Diseases like chicken pox, measles, mumps, influenza, encephalitis or other factors like noise exposure or head injury could all contribute towards developing hearing loss in children.
Poor functioning of the Eustachian tubes, perforated eardrums.
The use of ototoxic drugs that have the potential to damage the hearing apparatus may also lead to loss of hearing.
Hearing Loss in Adults: Otosclerosis
: This is an abnormal growth of bone near the middle ear and often causes conductive type of hearing loss. Sensorineuronal hearing loss (SNHL) can also occur in patients with otosclerosis
: This is a condition that causes spontaneous episodes of vertigo, i.e. a spinning motion. Other symptoms include fluctuating hearing loss, ringing in the ear (tinnitus), and sometimes a feeling of fullness or pressure in your ear. The exact cause is unknown. It is generally seen in the age group of 40 to 50 years (Though, children are not entirely spared). The hearing loss comes and goes, but it is reported that over a period of time, some loss becomes permanent.Presbycusis:
It is a sensorineural hearing loss, which affects hearing in both ears over a period of time. As the person ages, there is a progressive loss of ability to hear high frequencies. For men, it could start at an early age of 25 and women at 30. Teenagers and children could also be affected. Autoimmune inner ear disease:
This disease has been recognized as a potential cause for damage to the cochlea. One of the autoimmune conditions, which could cause hearing loss, is Wegener’s
. This is a sudden-onset hearing loss and could be quite dramatic.Medications/Chemicals:
Certain drugs can cause damage to the ear, which is irreversible in nature. Aminoglycosides such as gentamycin, neomycin, kanamycin as well as chemotherapeutic agents such as cisplatin is well-known to cause hearing loss. Other medications causing reversible type of hearing loss include diuretics, non-steroidal anti-inflammatory drugs, macrolide antibiotics, PDE5 inhibitors etc. NSAIDs such as ibuprofen are known to cause hearing loss in people who take it more than six times a week.
Metals such as lead, solvents such as toluene, styrene, xylene, ethyl benzene, carbon disulfide and automobile exhaust are also known to cause hearing loss.
Signs And Symptoms of Hearing LossInfants and Children:
Hearing loss in infants could be genetic. Premature birth or mother having viral infection during pregnancy such as toxoplasmosis, rubella may also affect hearing. A child may suffer from hearing loss after birth due to injury, tumor or infection. The doctor generally uses an otoscope to check the baby's ear canal and diagnose any problems. The signs and symptoms are as follows:
- The baby does not startle in response to a loud sound.
- The baby doesn’t respond when you are talking to him.
- The baby doesn’t turn head towards the source of sound like music
- The baby is not interested when you are shaking a rattle or playing with a musical toy.
- The baby does not respond to his/her name even after a few months
- Children generally start using single words by 12-15 months of age. A baby with hearing impairment might not be able to say simple words like "da-da" or ma-ma" and might not be able to pronounce many different consonant sounds at the beginning of words.
: Hearing loss could come about gradually or suddenly; in adults the signs and symptoms are as follows:
- Inability to hear people clearly.
- Difficulty in understanding people’s speech especially if it involves more than 2 people and there is background noise.
- Requesting people to repeat or clarify due to muffled hearing
- Turning up the volume to louder sound than usual while watching TV
- Limiting or avoiding social interactions
Lying or bluffing to someone when not hearing them due to the embarrassment in asking to repeat themselves frequently.
- Difficulty in hearing someone in noisy places like malls, restaurants, parties etc.
- Feeling of depression since hearing loss affects personal as well as social life.
Frequently Asked Questions (FAQs)1. Which doctor should I consult?
You could visit an otolaryngologist or an ENT doctor who specializes in diagnosis and treatment of ear, nose and throat disorders. Audiologists could also test, evaluate and treat hearing loss. Also, the hearing aid specialists are generally licensed by the board and state to test for hearing loss and are trained in fitting and dispensing hearing aids.2. How can I prevent hearing loss?
3. How is hearing loss measured and diagnosed?
- Stay away from excessive noise source such as firearms, power tools, motor boats, power boats. You could use headphones that block out these noises.
- If you work in a high-noise environment such as a factory, industry, mining, pub, dance club or construction site, then try and use earmuffs or earplugs to protect your ears.
- Do not keep the TV, radio, music system volume too loud. Remember, this is very important if you have young children because their ears are quite delicate. Avoid using headphones at maximum volume.
- Do not put fingers or any sharp instruments into your or your kids’ ears as this may cause damage to the eardrums.
- Visit your doctor if you or your child is experiencing any hearing problems.
There are a number of tools available for evaluation of hearing. An instrument called audiometer is used to determine a person’s sensitivity at sounds of different frequencies. Other tests include: Weber test, Rinne test, Tympanogram
, Acoustic reflex test.4. How is hearing loss graded?
The hearing level is typically measured in relation to 'normal' hearing in decibels (note: higher numbers of dB indicating worse hearing). They are graded as follows:
5. How often should a child have his or her hearing tested?
- Less than 25 dB in adults and 15 dB in children: Normal hearing
- 25-39 dB: Mild hearing loss
- 40-69 dB: Moderate hearing loss
- 70-94 dB: Severe hearing loss.
- 95+ dB: Profound hearing loss
- 100 db: complete deafness
When you suspect a hearing loss in your child, your doctor would most likely recommend testing using an Auditory Brain Response (ABR), which basically measures brain activity and does not require the child to respond. If the ABR reveals a hearing loss, then further testing is done for confirmation. Most audiologists recommend that children under three years of age should get their hearing tested every six months. After the age of 3, comprehensive hearing testing is recommended once a year.