Hearing Loss

Hearing loss is the partial or total loss of hearing in one or both ears. Loss of hearing can be temporary or permanent. Several disorders can affect the hearing in adults as well as children. If left untreated it can have a significant impact on your employment, education, and general well-being.

Types

The 3 common types of hearing loss include

• Conductive hearing loss: This is the condition where the sound is not conducted efficiently through the outer ear canal to the eardrum and the tiny bones of the middle ear (ossicles)
  
  
• Sensorineural hearing loss: This is the most common type of permanent hearing loss, resulting from damage to the tiny hair cells or to the nerve endings from the inner ear to the brain
  
  
• Mixed hearing loss: This type of hearing loss occurs in people who have both conductive and sensorineural types of hearing loss

Causes

Hearing loss can be congenital (present at birth) or acquired (may appear later). Common causes of conductive hearing loss include, ear infections, middle ear fluid, allergies, perforated eardrum, ear canal infection, benign tumors, impacted earwax, and anatomic abnormalities.

Some of the possible causes of sensorineural hearing loss include, illness, aging, head trauma, prolonged exposure to loud noises, certain drugs, and inner ear malformation.

Symptoms

The symptoms of hearing loss may be mild or severe and may develop gradually or suddenly.

Hearing loss may involve one or both ears. Symptoms may include, dull hearing, difficulty in understanding, ear pain, ringing or buzzing in the ear, itching, pus drainage, and vertigo (dizziness). Other symptoms include need for high volume when hearing radio or television, avoiding social situations, and depression.

Diagnosis

Your doctor will diagnose hearing loss by asking about your symptoms and with a detailed physical examination of the ears using a light instrument called otoscope. Your doctor may also recommend a standard hearing evaluation that comprises of

• Whisper test: This test checks the ability to hear and understand the whispered speech
  
  
• Tuning fork test: This test helps to differentiate conductive hearing loss from sensorineural hearing loss with the help of tuning fork
  
  
• Pure tone audiometry: This test determines how well a person can hear the sounds travelling through the ear canal and through the skull with the help of ear phones
  
  
• Speech reception and word recognition tests: To check your ability to hear and understand the speech
  
  
• Acoustic immittance tests (tympanometry): This test evaluates the middle ear's ability to receive the sound energy
  
  
• Otoacoustic emissions (OAE) testing: This test measures the sounds given off by the inner ear and is often used to screen newborns to help rule out hearing loss
  
  
• Auditory brain stem response (ABR) testing: This test may be used to test nerve pathways in the brain that help you in hearing

When an injury or tumour is suspected other imaging techniques such as X-ray of the head, CT or MRI scan of the head may be done.

Treatment

Treatment for temporary hearing loss depends on its cause and is often treated successfully. An ear infection is treated with the antibiotics, and blocked ear with earwax is treated by removing the wax using special instruments. In case of permanent hearing loss, hearing devices may be used to restore your hearing and to help you communicate more easily. Hearing devices such as assistive listening devices, alerting devices, television closed-captioning, and TTY (text telephone) may be used.

If the condition worsens a cochlear implant may be an option.
Cochlear implant is a small complex electronic device that is surgically placed within the inner ear to help make sounds. It consists of a microphone worn behind the ear, a speech processor worn on the body, and a transmitter worn on the head just behind the ear. A microphone picks up sound from the environment and sends them to the speech processor which selects, analyzes and digitizes the sound signals and sends them to a transmitter. This in turn sends these signals to the implant where the fibers of the auditory nerve are stimulated and sound sensations are perceived.