Dr. Dipalok Bandyopadhyay : kolkata, 28th October, 2025. Hearing impairment or deafness refers to the partial or complete loss of one of the most vital human senses — hearing. It signifies a decline or absence of the functional capacity of the auditory system. Across the world, nearly 500 million people currently suffer from hearing disorders, and the number continues to rise rapidly. By 2050, the number is expected to double, making hearing loss a major global health concern.
Anatomy of the Human Ear
Even higher secondary students are aware of the ear’s basic structure, which is divided into three parts — the outer ear, middle ear, and inner ear.
The Outer Ear extends from the visible ear opening to the tympanic membrane (eardrum).
The Middle Ear lies beyond the eardrum and houses three delicate bones — the malleus, incus, and stapes — along with small muscles and ligaments that amplify vibrations.
The Inner Ear, also called the labyrinth, resembles a coiled snail shell. The outer bony portion is the bony labyrinth, while the inner fluid-filled chamber is known as the membranous labyrinth, containing a special fluid called perilymph.
Sound waves strike the eardrum, causing it to vibrate. These vibrations are transmitted through the middle ear bones and amplified before reaching the cochlea. The movement of the fluid in the inner ear stimulates the hair cells of the organ of Corti, which convert mechanical vibrations into electrical impulses. These impulses travel through the auditory nerve to the temporal lobe of the brain, where sound is finally perceived.
Thus, any defect along this auditory pathway — from the outer ear up to the auditory cortex — can result in partial or total hearing loss.
Types of Hearing Loss
Hearing loss is broadly classified into two main categories:
1. Conductive Hearing Loss – when sound waves cannot efficiently pass through the outer or middle ear.
2. Sensorineural Hearing Loss (Nerve Deafness) – when the inner ear (cochlea) or auditory nerve is damaged.
Congenital Deafness (Since Birth)
Some individuals are born deaf or hard of hearing due to structural or genetic abnormalities. Common causes include:
Genetic or hereditary defects
Maternal infections during pregnancy (e.g., rubella, measles, mumps)
Repeated X-ray exposure or use of harmful drugs during pregnancy
Complications during delivery (e.g., forceps delivery, birth injury, premature birth)
Rh incompatibility (mother Rh-negative, father and child Rh-positive)
Consanguineous marriage (marriage among close relatives)
Approximately 4 in every 1,000 newborns suffer from congenital hearing impairment.
Warning signs in infants:
At 2 months, a loud clap should make the baby blink or close their eyes.
At 4–5 months, the baby should move their eyes or head toward a sound.
At 6 months, they should turn toward the source of a voice.
By 18 months, they should start forming simple two-word phrases.
Any delay in these milestones warrants an immediate consultation with a physician.
Acquired Hearing Loss (After Birth)
Acquired hearing loss can occur due to multiple causes. The major ones include:
Head or ear injury
Middle or inner ear infections
Tumors or abnormal growths
Ménière’s disease
Diabetes mellitus
Cerebral thrombosis or stroke
Ototoxic drugs, such as:
Streptomycin, Gentamicin, Amikacin, Neomycin
Quinine, Chloroquine
Furosemide
High-dose Aspirin or Salicylates
Certain anticancer, tuberculosis, or psychiatric medicines
Outer Ear Problems:
Wax accumulation, inflammation, or foreign objects.
Middle Ear Problems:
Boils or abscesses, chronic discharge (otitis media), perforated eardrum, or fixation of ossicles.
Inner Ear Problems:
Congenital defects, viral infections (mumps, measles, rubella), high blood pressure, diabetes, or bacterial/fungal infections — all may cause temporary or permanent hearing loss.
Noise Pollution — The Silent Killer of Hearing
Excessive sound exposure is a leading modern cause of deafness.
Sound levels above 60–70 decibels (dB) can damage the ear.
High-risk groups include:
Factory and construction workers
Drillers and machine operators
Musicians, singers, and DJs
Stone-crushers and industrial laborers
Motor drivers and traffic police officers
Regular audiometric screening is essential for individuals in such professions.
In recent years, headphone and earphone misuse has become a growing threat among youth. Loud music played at 100–110 dB destroys delicate cochlear hair cells irreversibly.
Safe listening practices:
Keep the volume at moderate levels.
Take a 5-minute break after every 30 minutes of listening.
Avoid sleeping with earphones plugged in.
Tinnitus — The Ringing Ears
When cochlear hair cells are damaged, patients often hear continuous ringing, buzzing, or humming sounds — a condition known as tinnitus.
In the United States alone, over 50 million people suffer from this problem. Severe tinnitus can lead to sleep loss, irritability, and depression.
Important advice:
Do not insert any objects into your ear. Avoid cleaning with matchsticks, pins, or cotton buds. Do not pour milk, oil, or any drops without medical advice.
Balance and the Ear
Apart from hearing, the ear also helps maintain body balance through its vestibular system.
When this part is affected, the patient experiences vertigo, giddiness, or unsteady walking. In severe cases, hearing aids or cochlear implants may be required.
Age-Related Hearing Loss (Presbycusis)
With advancing age, hearing gradually declines, just like eyesight. The hair cells in the cochlea degenerate, the inner ear fluid dries up, and the auditory nerve weakens. Elderly people often fail to recognize or admit this problem, relying instead on lip-reading during conversations.
Simple self-care measures:
Close your mouth, gently block both ears with fingers, and exhale slowly through the nose — this may help unblock the Eustachian tube.
Lie down with the affected ear facing upward.
If the ear remains blocked, apply a few drops of lukewarm olive oil or 3–4 drops of hydrogen peroxide (only if advised by a doctor).
Common Sound Levels (for Awareness)
Type of Sound Approx. Decibel (dB) Level
Whisper 30 dB
Normal conversation 60 dB
Motorcycle engine 90 dB
Headphones at full volume 100–110 dB
Taking early preventive measures can help avoid permanent hearing damage.
A Global Call for Awareness
Recognizing the importance of hearing health, the last Sunday of September is observed as “International Deaf Day” across the world. The day emphasizes the need for awareness, prevention, and timely treatment of hearing disorders.
So, while you have ears — value them, protect them, and listen wisely.
Once lost, the power to hear is seldom regained, and with it, life loses one of its sweetest symphonies.
“Understand your ears before it’s too late —
For hearing is not just a sense, it’s a bridge to life itself.”
