What is Hearing Loss? All FAQs Answered

Hearing loss or hearing impairment is our inability to hear. The hearing loss or deafness can be partial or total, the levels of hearing loss depend on the results of the audiometry test. The hearing thresholds determine if the hearing loss is mild, moderate, or severe. Detailed testing is required to diagnose the causes of hearing loss.

The following are some of the causes of hearing loss.

• Presbycusis (Age-related deafness)
• Diabetes
• High blood pressure
• Heart condition
• A stroke
• Brain injury
• Tumor
• Viral and bacterial ear infection
• Earwax build-up
• Ruptured eardrum
• Abnormal bone growth
• Noise induced hearing loss
• Heredity
• Ototoxicity
• Measles
• Meningitis
• Mumps

For more details read Causes of hearing loss and symptoms.
Read to know about Diseases that cause hearing loss

The 4 types of hearing loss are:

• Sensorineural hearing loss
• Conductive hearing loss
• Mixed hearing loss
• Auditory Neuropathy Spectrum Disorder

(Courtesy: Centers for Disease Control and Prevention)
For more information read Types of hearing loss explained

The common symptoms of hearing loss are:

• Difficulty in following the conversation when a person talks from behind or is some distance away
• Trying to lip-read while talking
• Unable to hear well while in a group discussion, like an office meeting or a family get-together.
• Inability in following the conversation if the conversation is in a noisy area, like a restaurant or while travelling on a public transport
• At times the affected person can hear but the words are not clear or sound muffled
• Unable to locate the source of sound if someone calls out.
• Missing out on every day sounds like birds chirping or raindrops
• Unable to hear the doorbell or the ring of the telephone.
• Missing out on words in a telephone conversation
• Having difficulty in following conversation with children and ladies as compared to males. (High frequency hearing Loss)
• The affected person increases the volume of the television or the music system.
• A person in the initial stages of deafness will complain about others not speaking loud enough or clearly
• The person with hearing loss will request others to repeat themselves
• A person with hearing loss gradually withdraws from family discussions and social events
• The affected person will show signs of tiredness as they have to strain themselves to hear.

Read to know more about causes of hearing loss and symptoms

The following are some of the causes of deafness at birth:

• Premature birth
• Low birth weight
• Birth injuries
• Infections such as rubella or herpes simplex virus
• Jaundice from a blood transfusion
• Mother suffering from diabetes
• Complications during delivery, for example, lack of oxygen
• Alcohol or drug abuse by the mother during pregnancy
• Mother having high blood pressure during pregnancy
• Inheriting the hearing loss gene from one of the parents (Autosomal dominant hearing loss)
• Down syndrome, Usher syndrome, Crouzon syndrome
• Ear deformity (Anotia or Microtia)

For more information read Hearing loss in children – what every parent should know
Also, read Congenital deafness – causes and treatment options

Sensorineural hearing loss (SNHL) or sensorineural deafness is hearing loss due to damage or defect in the inner ear or nerves. Defects or damage to the inner ear reduces the sensitivity of the sensory and neural parts of the ear.

Hearing loss in both ears is known as bilateral sensorineural hearing loss.
Hearing loss in one ear is known as unilateral sensorineural hearing loss.
Sensorineural hearing loss is also known as nerve deafness.

For more information read Sensorineural hearing loss – symptoms, causes and remedies

Some of the causes of sensorineural hearing loss are:

• Deafness due to old age, known as presbycusis
• Exposure to loud sounds
• Injury to the inner ear
• Infections such as meningitis, mumps, and measles
• Genetics or family history of hearing loss
• Ototoxicity due to medicines
• Acoustic neuroma
• Diseases like diabetes, cardiac issues, hypertension, etc.

Conductive hearing loss is deafness due to the inability of the outer or the middle ear to conduct sound waves to the inner ear.

In case there is any obstruction or defect in the outer ear or the middle ear, the sound waves are not transmitted successfully to the inner ear. In this case, the person is unable to hear well or suffers from conductive hearing loss or conductive deafness.

For more information read Conductive hearing loss – symptoms causes and treatment

Some of the common causes of conductive deafness are as under:

• Earwax accumulation
• Obstruction by an external object
• Ear infection
• Fluid accumulation in the middle ear
• Malformation of the outer ear (Aural atresia, microtia)
• Abnormal bone growth
• Perforated eardrum
• Otosclerosis
• Injury to the ear due to accident
• Benign tumors
• Poor eustachian tube function

In the majority of the cases, conductive hearing loss is not permanent. Most of the causes of conductive hearing loss can be treated surgically or with antibiotics. Causes like earwax accumulation, physical obstruction, ear infection, and fluid accumulation can be successfully treated.

Conductive hearing loss causes like stenosis of the ear canal, exostosis, otosclerosis, and ossicular chain discontinuity are difficult to treat.

The following are some of the causes of hearing loss in one ear or unilateral hearing loss:

• Earwax accumulation
• Ear infections (viral or bacterial)
• Ruptured eardrum
• Acoustic neuroma
• Ménière’s disease
• Abnormal bone growth in the ear
• Physical damage to the ear
• Pressure on the hearing nerve
• Circulatory system disorders
• Genetic or inherited disorders
• Chemotherapy drugs
• Ototoxicity due to antibiotics
• Tumor

The common unilateral hearing loss causes in children are:

• Mumps
• Otitis Media (Middle ear infection)
• Congenital Cytomegalovirus (CMV)
• Meningitis

For more information read Hearing Loss in One Ear – Causes and Treatment

The factors that can cause sudden hearing loss or SSHL are:

• A tumor on the auditory nerve
• Infectious diseases like Lyme Disease
• Autoimmune diseases (Cogan’s syndrome)
• Trauma to the head or spine
• Exposure to ototoxic drugs
• Reduced blood circulation to the ear
• Prolonged exposure to loud sounds
• Continuous stress
• Untreated chronic middle ear infection
• Neurological problems like multiple sclerosis and inner ear disorders like Meniere’s disease.

For more information read Sudden hearing loss symptoms, causes and treatment.

Mixed hearing loss is a combination of sensorineural hearing loss and conductive hearing loss, both types of deafness occur at the same time.

A common example is someone with a sensorineural hearing loss having a middle ear infection or Eustachian tube congestion. The factors responsible for the conductive hearing loss can be treated but the sensorineural loss is permanent.

A high frequency hearing loss is the inability of the ear to hear sounds and speech in the high frequency range. These high frequencies are above 2000 Hertz. It is also referred to as high pitch hearing loss.

Missing out or being unable to understand words that start with “S”, “H”, “F” or sounds like “SH” (hissing sounds) are a sign of high frequency sensorineural hearing loss. it mostly affects the elderly population.

For more information read High frequency hearing loss – symptoms, causes & remedy

Noise induced hearing loss (NIHL) is deafness caused by exposure to loud sounds over a period of time or excessively loud sounds for a short time. Continuously listening to loud music or being near an explosion can cause noise induced hearing loss.

Sound levels of 70 dBA and above are considered harmful, below are the noise levels and the period of exposure that can damage the sensitive hair cells in the cochlea. NIHL is sensorineural hearing loss and is mostly permanent.

• 85 dBA – for a few hours.
• 100 dBA – continuous exposure of 14 minutes and more.
• 110 dBA – continuous exposure of 2 minutes and more.

Read about the Simple ear health tips to prevent noise induced hearing loss.
(Courtesy: https://www.noisyplanet.nidcd.nih.gov/parents/too-loud-too-long)

Ototoxicity is the side effect or adverse reaction of certain drugs that affect the inner ear or the auditory nerve. Ototoxicity literally means a substance or medicine that is toxic or poisonous to our ear (Oto–Greek word for ear).

Ototoxicity is also known as drug induced hearing loss; besides deafness, it can affect our balance and also cause tinnitus. Known ototoxic drugs include aminoglycoside antibiotics and cancer chemotherapy drugs, such as cisplatin and carboplatin.

The effects of ototoxic drugs can be reversed if the reaction is detected and the drug therapy is discontinued before permanent damage takes place.

Read about Ototoxic medicines for more information.

Otosclerosis is an abnormal bone growth in the middle ear that causes hearing loss. The literal meaning of Otosclerosis is Oto (concerning the ear) and sclerosis (abnormal hardening of body tissue).

Our middle ear has 3 tiny bones that vibrate when sound enters our ear, these vibrations are transmitted to the inner ear. The abnormal growth around stapes, one of the bones in the middle ear limits its ability to vibrate.

Due to the limitation or inability of the bone to vibrate, it cannot efficiently transmit sound to the inner ear. This results in hearing loss.

There is ample evidence to support that hearing loss affects the brain, especially the region that processes cognitive activities. Cognitive activities are intellectual activities such as thinking, reasoning, and remembering, to name a few. People with hearing loss are twice as much likely to develop cognitive impairment.

The simple reason is that if one hears less, there are fewer signals for the brain to process which leads to reduced stimulation. When a deaf person is straining to hear, there is a cognitive overload and the brain works hard to understand what others are saying. Since the brain is working hard to understand speech, it cannot perform other functions that are cognitively demanding.

That is the reason why people with hearing loss cannot remember much or are prone to falling, since body balance is also a function of our inner ear.

The use of hearing aids reduces cognitive impairment.

Read Use of hearing aids for elders – 5 helpful tips to convince them

You finish your audiometry test and your audiologist informs you that you have a profound hearing loss or severe hearing loss or moderate hearing loss. These are the levels of hearing loss or the degree of hearing loss one suffers from.

The hearing loss mentioned in your audiogram is classified as under:

• Mild Hearing Loss 26 to 40 dB
• Moderate Hearing Loss 41 to 55 dB
• Moderately Severe Hearing Loss 56 – 70 dB
• Severe Hearing Loss 71 – 90 dB
• Profound Hearing Loss 91 dB and above

A normal person can hear a sound that is around 20-25 dB, however, a person suffering from severe hearing loss can only hear if the sound level is more than 70 dB.

Bilateral hearing loss is a deafness in both ears. Age-related hearing loss which has developed gradually is generally bilateral.

If the hearing loss in both ears is equal, it is known as symmetrical hearing loss. If the hearing loss in one ear is more than in the other, it is known as asymmetrical hearing loss.

In case of asymmetrical hearing loss, people tend to use only one hearing aid. It is important that hearing aids are used in both ears.

For more information read Are 2 Hearing Aids Better Than 1?

Profound hearing loss is the inability of the person to hear any sound below 90dB. A pure tone audiometry test level of an average 90 dB and above is considered a profound hearing loss.

Most everyday sounds are much below this level, a person having profound deafness cannot hear speech at a normal conversational loudness that is between 30 – 60 dB. An ambulance or police siren or a car honking nearby will cross the 90 dB sound level.