Understanding how you hear and the causes of permanent hearing loss can help you to prevent potentially life devastating problems.

Sound waves are received by the tympanic membrane and conducted to the inner ear via three bones found in the middle ear – maleus, incus and stapes.

From there, it is converted into complex sound signals and percolated through the cochlea.

It is then conducted to the auditory cortex via the auditory nerve.

Hearing loss can be temporary or permanent.

Causes of permanent hearing loss are:

• Congenital rubella – if the mother suffers from rubella early in her pregnancy (in the first three months), the child will usually be deaf by birth. This is a type of congenital deafness and it is usually permanent. Both the ears are affected.
• Meniere’s disease – is a disease of the inner ear. There is a continuous rise in the amount of endolymph in the cochlea which creates pressure over the nerve ending present inside it. Meniere’s disease is commonly seen in one ear, but can be of bilateral as well. The deafness is progressive and complete.
• Trauma – permanent damage to the tympanic membrane can occur due to injury, sudden exposure to a very loud noise in the case of an explosion or diseases of the middle ear. As the tympanic membrane is damaged, sound waves cannot pass through to the middle ear bones causing permanent hearing loss.
• Acoustic neuroma – a tumor of the eighth cranial nerve (auditory nerve). Usually unilateral, acoustic neuroma gives a symptom of fullness in one ear along with deafness.
• Genetic disorders – some genetic disorders like Treacher-Collin syndrome, Down syndrome, Crouzon syndrome are insignificant causes of permanent hearing loss.
• Head injury – injury to the cerebral cortex controlling the sense of hearing can lead to permanent deafness.
• Otitis media – if it reaches the auditory nerve and causes damage, it will likely cause permanent hearing loss.
• Some medicines (like aspirin, chemotherapy drugs, aminoglycosides) if taken for a long enough time can damage the auditory nerve.

These are the most common causes of permanent hearing loss.

If you cannot perceive sound properly, consult an ear, nose, and throat specialist before jumping to any conclusions.