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Common Forms of Hearing Loss

More than 37 million people in the U.S. have a hearing loss that impacts their abilities to communicate.  Hearing loss occurs as a result of some form of damage or malfunction within the auditory system. A variety of factors can cause damage or malfunction. Some forms of hearing loss are hereditary, while others can stem from infections, aging, medications, disease, head injury or excessive noise exposure.  In rare instances hearing loss can result from an acoustic neuroma (aka vestibular schwannoma or VS) -- a tumor occurring on the balance nerve. 

Some types of hearing loss may be signs of a serious medical condition. If you notice a sudden change in your hearing or an onset of asymmetrical or unilateral hearing loss (hearing loss in one ear), you should have an evaluation by an ear specialist – an otolaryngologist (ENT), otologist or neurotologist. A complete otologic examination by an ear, nose and throat (ENT) physician can determine what type of hearing impairment may exist, its possible causes, and treatment options. 


 

Experience what it is like to have a hearing loss with this Flintstones video. (used with permission). ©HEI

Conductive Hearing Loss
Hearing loss can be conductive or sensorineural in nature. Conductive hearing loss occurs when excessive earwax or a disease or disorder, such as damage to the eardrum or middle ear bones due to infection or otosclerosis1, impedes the ability of either our middle or outer ear to transmit sound to the inner ear. Medication and/or surgical reconstruction techniques often can correct mechanical functions of the eardrum or ossicular chain. Blockage of the outer ear canal also can result in hearing loss. In such cases, an ENT physician often can provide treatment to improve hearing.

Sensorineural Hearing Loss
Sensorineural hearing loss is nerve-based. It occurs when either the microscopic hair cells of the inner ear or nerve fibers, which transmit signals to the brain, are damaged or compromised. In most cases, this type of hearing loss is permanent and irreversible. 


In Cases of Sudden Sensorineural Hearing Loss, Urgent Treatment Matters

Sudden sensorineural hearing loss (SSHL) can be a frightening experience for anyone who has gone through it.  But many people are unaware of how critical it is to seek urgent medical care when it occurs.

The onset usually takes place within the span of 72 hours.  Hearing is reduced by more than 30 decibels over at least three contiguous frequencies, and often affects only one ear.  SSHL is associated with dizziness in 25% of patients.  Tinnitus (sensations of ringing in the ear) is also common.

According to the National Institute on Deafness and Other Communication Disorders, approximately 4,000 new cases of SSHL occur each year in the United States. It can affect anyone, but it most often happens to people between the ages of 30 and 60.

“Often there is a delay in diagnosis of SSHL,” said Rick A. Friedman, M.D., Ph.D., a House Clinic neurotologist.  “But patients should seek medical advice immediately to increase their chances of hearing restoration in the affected ear.” 
There are a variety of possible causes for SSHL.  “Theories include that it is viral, or related to ruptures of the inner ear membranes and vascular occlusion,” said Dr. Friedman.  “Occasionally, it can be the result of an acoustic neuroma.”
People who experience SSHL should contact their local physician or ENT specialist without delay.  To reach an ear specialist in the L.A. based House Clinic, call (213) 273-8000 or e-mail info@hei.org.

 

 

Microscopic Normal Hair Cells

   Microscopic Damaged Hair Cell

Sensorineural damage can be caused by a genetic disorder, such as in cases of congenital hearing loss, or certain age-related loss, such as presbycusis. Disease and high fever also can trigger it. Damage can be induced by high dosages of ototoxic medications2 and excessive exposure to loud noise -- refer to the section on Protecting Your Hearing Health.  Fluctuating hearing loss can be an indication of Meniere’s disease,  an abnormality of the inner ear causing a host of symptoms, such as severe dizziness, tinnitus, fluctuating hearing loss usually in one ear, and the sensation of pressure or pain in the affected ear.
 
Someone who has a sensorineural loss may hear people talking but may not be able to understand what they are saying. An increase in the loudness of speech may only add to his or her confusion. The person will usually be able to hear better in quiet places, but may have difficulty understanding what is being said over a telephone. Usually, low tones will tend to be heard more easily than high tones; therefore, a man's voice may be easier to understand than that of a child or woman with a higher pitched voice. Doorbells, high-pitched alarms, sirens, and ringing telephones also may be difficult to hear. Recent advances in hearing aids can, in many cases, help people with this type of hearing loss. 

Hearing aids at the House Clinic

Tips on communicating
with someone who has a hearing loss

   Mixed Hearing Loss
Sometimes people can have a combination of conductive and sensorineural impairment, commonly referred to as a mixed hearing loss.  Multiple disorders or a single disease, such as otosclerosis that can spread to both middle and inner ear structures, can result in a type of mixed hearing loss.

Medications can effect your hearing
Certain medications may cause temporary or permanent hearing-related side effects in some individuals at certain dosages. Categories of these medications include salicylates and other anti-inflammatory agents, aminoglycosides, hydrocodone, antineoplastics (for cancer chemotherapy), loop diuretics, and cinchona alkaloids. Contact your physician if you are concerned about a particular medication that you are taking. For more information see Ototoxicity


Tinnitus
Hearing loss is one of many different health factors that can be associated with tinnitus, a symptom usually identified as a ringing or roaring sensation in the ear. Approximately 80% of patients with hearing loss report experiencing tinnitus. While some degree of head noise is a normal occurrence in everyone, it can be debilitating for some people. In the latter case, a licensed physician should be consulted to check for a serious medical condition. Audiologists and other trained professionals can offer devices and techniques to help manage or minimize debilitating tinnitus, and patients sometimes get relief through stress control, ample rest, exercise, and avoidance of caffeine and other dietary stimulants. <Click for more information> 

Links to more information:  

"Tinnitus: The Noise Within" - House Calls Magazine

 
For more information, the House Ear Institute and USC's Ethel Percy Andrus Gerontology Center have partnered to offer the following online hearing educational course:

Hearing and the Aging Ear
 
 
1 Otosclerosis is a common hereditary disease that typically affects the mobility and function of the stapes bone by producing an abnormal growth of spongy bone along the walls of the middle ear. This type of specific type of common impairment is called stapedial otosclerosis and is often correctable by surgery.  When otosclerosis spreads to the inner ear, it is called cochlear otosclerosis, and can cause a permanent sensorineural hearing impairment due to interference with the nerve function.