What are the other Names for this Condition? (Also known as/Synonyms)

• Nerve Deafness
• Perceptive Hearing Loss
• Sensory-Neural Hearing Loss

What is Sensorineural Hearing Loss? (Definition/Background Information)

• Sensorineural Hearing Loss is a type of hearing loss that results from a problem in the inner ear. The inner ear contains hair cells that are responsible for detecting the sound waves and producing the electrical signals for the brain
• The brain interprets these signals as sounds. When these hair cells are missing or damaged, the individual would have a condition, termed as Sensorineural Hearing Loss. It is the most common type of hearing loss or deafness
• Most cases of Sensorineural Hearing Loss are irreversible (permanent) and associated with a poor prognosis; they may not be prevented too. However, some cases can be prevented if they are caused by chronic exposure (for a long period of time) to loud noises or certain medications

Who gets Sensorineural Hearing Loss? (Age and Sex Distribution)

• Sensorineural Hearing Loss may occur at any age
• Both males and females can be equally affected

What are the Risk Factors for Sensorineural Hearing Loss? (Predisposing Factors)

The most common risk factors of Sensorineural Hearing Loss are:

• Premature birth (born before 37 weeks or too early)
• Hereditary causes (hearing loss that runs in the family)
• Exposure to loud noises (may be due to one’s occupation)
• Older age

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Sensorineural Hearing Loss? (Etiology)

The causes of Sensorineural Hearing Loss are either congenital (present at birth) or acquired (that happens after birth).

Congenital causal factors:

• Hereditary - inherited from the family
• Spontaneous mutation (alternation in the DNA)
• Waardenburg Syndrome: A disorder that causes hearing loss, white hair, and changes in coloring of the skin and eyes
• Jerveil and Lange-Nielsen syndrome: A disorder characterized by hearing loss and irregular heartbeats
• Pendred syndrome: A disorder that causes hearing loss and an enlarged thyroid gland
• Usher’s syndrome: A disorder that causes hearing loss and progressive vision loss
• Low birth weight
• Mother having an infection during pregnancy, such as:
  • Toxoplasmosis
  • Rubella
  • Herpes
  • Cytomegalovirus
  • Syphilis
• Hypoxia (lack of oxygen) during birth

Acquired causal factors:

• Infections, such as:
  • Bacterial meningitis - an infection of the membranes covering the brain and spinal cord
  • Measles
  • Mumps
• Head trauma
• Presbycusis - age-related hearing loss
• Exposure to loud noises, especially over a long period of time
• Meniere’s disease: An inner ear disorder causing tinnitus or ringing in the ears, hearing loss, the sensation of ear fullness, and vertigo (or a feeling that the room is spinning)
• Tumors - acoustic neuroma: A benign and slow-growing tumor of the nerve that connects the inner ear and brain
• The use of certain medications, such as:
  • Antibiotics
  • Aspirin (used for pain relief and heart conditions)
  • Quinine (to treat malaria)
  • Loop diuretics (to treat certain heart and kidney conditions)
  • Platinum-containing chemotherapeutic agents
• Exposure to heavy metals (such as mercury and lead)

What are the Signs and Symptoms of Sensorineural Hearing Loss?

The signs and symptoms of Sensorineural Hearing Loss may include:

• Difficulty hearing
• Some sounds sound too soft
• Difficulty following conversations
• Difficulty hearing in noisy areas
• Other people’s speech sound mumbled or slurred
• Frequently asking other individuals to repeat what they are saying

Infants with Sensorineural Hearing Loss may:

• Not respond to sounds, by turning towards the sound or imitating the sound
• Not startle, when there is a loud noise
• Not babble by 12 months of age
• Not respond to his/her name by 12 months of age
• Not use a single word, even at  the age of 18 months
• Have delayed vocabulary compared to his/her peers
• Have an unclear speech

How is Sensorineural Hearing Loss Diagnosed?

A hearing loss is diagnosed based on the individual’s history, behavior, physical exam, and audiological (hearing) exam. The physician or audiologist may order a variety of tests for Sensorineural Hearing Loss, which may include:

• Otoscopy: Examination using an instrument that allows the physician to look inside the ear
• Weber test: A test in which a vibrating tuning fork is placed on the midline of the head
• Rinne test: A test in which a vibrating tuning fork is held next to the ear and then in front of the ear, until the individual no longer hears the sound
• Audiometric test: Hearing tests that involve listening to different tones
• Tympanometry: A test that puts air pressure in the ear canal in order to move the eardrum, and then measures the eardrum mobility (movement)
• Acoustic reflex: A test that stimulates the stapedius (a tiny ear muscle) to move, in response to a loud sound
• Static acoustic measures: A test that measures the amount of air in the ear canal
• CT scan or MRI scan of the head
• Auditory brainstem response: A test that places electrodes on the scalp and measures the electrical response of the brain to sounds
• Otoacoustic emissions: A test in which a tiny microphone is placed in the ear, plays sounds, and measures the signals produced by the inner ear

All newborns should have a hearing screening. If they do not pass a hearing screening, then they are seen by an audiologist (the health professional who measures hearing loss) for a complete hearing exam.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Sensorineural Hearing Loss?

The complications of Sensorineural Hearing Loss may include:

• Depression
• Anxiety
• Withdrawal from social interactions

How is Sensorineural Hearing Loss Treated?

There is no cure for Sensorineural Hearing Loss. However, the treatment for the condition may involve the use of hearing aids or cochlear implants:

• A hearing aid, a small electronic device to amplify sounds (increase the volume), may be worn in or behind the individual’s ear
• A cochlear implant is an electronic device that is surgically implanted into the inner ear. Instead of amplifying and making the sounds louder, like the hearing aid, the cochlear implant bypasses the inner ear and directly stimulates the auditory nerve. It converts sound waves to electrical signals, which are then sent to the brain

Some individuals may use telephone amplifiers, lip reading, visual aids, and sign language, to communicate with others.

How can Sensorineural Hearing Loss be Prevented?

Depending on the causal factors, some cases of Sensorineural Deafness (or Sensorineural Hearing Loss) may be prevented.

• If the disorder is caused due to noise exposure, it may be prevented by avoiding loud noises and wearing suitable ear protection gear (like ear plugs or ear muffs), when exposed to loud environment
• Sensorineural Hearing Loss due to ototoxic medications (drug-induced hearing loss) can be prevented by avoiding such medications

However, if the disorder is caused due to congenital and hereditary factors, aging, and infections, it cannot be prevented.

What is the Prognosis of Sensorineural Hearing Loss? (Outcomes/Resolutions)

The prognosis of Sensorineural Hearing Loss depends on the cause; but, in most cases the prognosis is usually poor.

Additional and Relevant Useful Information for Sensorineural Hearing Loss:

• According to the World Health Organization, there are around 360 million people (representing over 5% of the world’s population), with some form of hearing loss
• 9 out of every 10 children, who are born deaf, are born to parents, with a good hearing sense
• Conductive hearing loss is a type of hearing loss that results from a problem in the outer ear or middle ear. It is often a temporary disorder and can be treated with medication or surgery