Causes of hearing loss

There are 2 types of hearing loss :

Conductive Hearing Loss occurs when sound waves cannot be transmitted properly from the external environment to the cochlea. The problem could lie in the external ear canal, eardrum, middle ear bones or middle ear space.

Common Causes of Conductive Hearing Loss include :

• Obstruction in the external ear canal caused by wax, foreign body or infection (otitis externa).
  
• Perforated eardrum – usually a result of trauma or chronic infection.
  
• Dislocated, damaged or fi xed ossicles (malleus, incus, or stapes) – from trauma or chronic diseases that erode the ossicles over time or otosclerosis that cause the ossicles to be fixed.
  
• Otitis media – a middle ear infection, usually with fl uid in the middle ear space.

Common causes of hearing loss include:

• Ageing (presbycusis)
• Acute and chronic exposure to loud noise can cause damage to the sensory cells in the cochlea.
• Infections of the inner ear by viruses and bacteria such as mumps, measles and infl uenza.
• Ménière disease - a disease that causes tinnitus, hearing loss and dizziness.
• Acoustic neuroma - a tumour of the vestibular nerve, which lies in close proximity to the auditory nerve and affects its function.
• Ototoxic drugs – Some drugs can damage the nerves involved in hearing or the sensory cells in the cochlea. Examples include:
• Antibiotics including aminoglycosides (gentamicin, vancomycin),
• Diuretics including frusemide
• Antineoplastics (cancer drugs)