• India
  • Jun 19
  • Kevin Savio Antony

Explainer - What is Sensorineural hearing loss?

Playback singer Alka Yagnik revealed she has been diagnosed with a rare sensory hearing loss a few weeks ago.

What is Sensorineural hearing loss?

• The ear, like any other organ, can experience failure leading to a sudden loss in hearing.

• Sensorineural hearing loss (SNHL) is a type of hearing loss that occurs due to damage to the inner ear or the hearing nerve. 

Hearing Mechanism:

• The cochlea, a spiraling organ inside the inner ear, contains tiny hair cells known as stereocilia.

• These hair cells convert sound wave vibrations into neural signals, which are then carried to the brain by the auditory nerve.

• Exposure to sounds louder than 85 decibels can make the stereocilia fragile and eventually damage them.

• This damage impacts hearing and the effects are typically noticeable only after 30-50 per cent of the hair cells are damaged.

• The degree of hearing loss can range from mild to severe, depending on the extent of damage to the hair cells.

What causes Sensorineural hearing loss?

1) Congenital Causes:

• Infections: Congenital infections such as rubella, cytomegalovirus, and herpes can lead to Sensorineural hearing loss (SNHL).

• Complications at Birth: Conditions like anoxia (lack of oxygen), jaundice, low birth weight, and prematurity can contribute to SNHL.

2) Acquired Causes:

• Exposure to Loud Noises: Prolonged or repeated exposure to sounds louder than 85 decibels can damage the hair cells in the cochlea.

• Natural Ageing Process: Age-related hearing loss (presbycusis) is a common cause of SNHL.

• Head Trauma: Injuries to the head can damage the inner ear or auditory pathways.

• Autoimmune Disease: Autoimmune disorders can attack the inner ear, leading to hearing loss.

• Meniere’s Disease: A disorder affecting the inner ear, causing vertigo, tinnitus, and hearing loss.

• Circulation Problems: Reduced blood flow to the inner ear can result in hearing impairment.

• Side Effects of Certain Drugs: Ototoxic medications, such as certain antibiotics and chemotherapy drugs, can damage the inner ear.

3) Viral Infections and Inflammation:

• Common Viral Causes: Viral infections, especially by the herpes virus, are significant contributors to SNHL.

• Mechanism of Viral Damage: The herpes virus can directly invade the auditory nerves, infect the fluid spaces of the inner ear, or trigger an autoimmune response in the inner ear.

(The author is a trainer for Civil Services aspirants.)

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