Hearing loss occurs when there is a problem with one or more parts of the ear.
In air conduction, sound waves travel through the external ear canal to vibrate the eardrum. Vibration of the eardrum is transmitted to the hearing organ (cochlea) via three small bones (ossicles) in the middle ear. This stimulates the sensory cells in the cochlea which then sends impulses to the hearing nerve (auditory nerve) and on to the brain.
Hearing by bone conduction occurs when sound waves cause the bones of the skull to vibrate which directly stimulate the hearing organ (cochlea) resulting in hearing.
Noise-induced hearing loss is usually irreversible and progresses with each exposure. People who work with heavy machinery or in the construction industry should use proper ear protection when working around loud noises, especially when working for prolonged periods. They should also undergo regular hearing tests to ensure that their hearing is not worsening.
Young people should refrain from using earphones at high volumes, and limit prolonged exposure to loud music to prevent premature damage.
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:
Common causes of hearing loss include:
A complete history, ENT examination and relevant investigations are necessary for a diagnosis. The ENT physician will perform a thorough head and neck examination, particularly of the ear canal and tympanic membrane. An endoscopic examination of the nose and nasopharynx may also be necessary. Occasionally, a neurologic examination will be done.
A hearing test (audiogram) will be performed to confirm the presence and indicate the severity and type of hearing loss. A tympanogram may also be performed to detect problems of the eardrum and middle ear. Radiological imaging studies such as CT scans or MRIs (magnetic resonance imaging) may be ordered to detect an acoustic neuroma.
Medical treatment depends on the underlying problem. Treatment may range from observation and reassurance to medications and a discussion on surgical options. If the cause of hearing loss is due to wax and foreign body in the ear canal, it can be removed under a microscope by the ENT surgeon.
In cases of external ear infections, topical antibiotic is needed. If there is an eardrum perforation, the underlying infection has to be treated. Surgical repair of the ear perforation may be necessary if the perforation persists for more than three months or there is a problem of recurrent ear infections with ear discharge. If the cause of the hearing loss is due to medication, the medication will be stopped or changed.
For presbycusis (hearing loss due to old age) no treatment is needed although the affected individual will be advised to protect his hearing and evaluated on whether hearing aid help is needed.